*Peristalsis*, i.e., a motion pattern arising from the propagation of muscle contraction and expansion waves along the body, is a common locomotion strategy for limbless animals. Mimicking peristalsis in bio-inspired robots has attracted considerable attention in the literature. It has recently been observed that maximal velocity in a metameric earthworm-like robot is achieved by actuating the segments using a “phase coordination” principle. This paper shows that, in fact, peristalsis (which requires not only phase coordination, but also that all segments oscillate at same frequency and amplitude) emerges from optimization principles. More precisely, basing our analysis on the assumption of small deformations, we show that peristaltic waves provide the optimal actuation solution in the ideal case of a periodic infinite system, and that this is approximately true, modulo edge effects, for the real, finite length system. Therefore, this paper confirms the effectiveness of mimicking peristalsis in bio-inspired robots, at least in the small-deformation regime. Further research will be required to test the effectiveness of this strategy if large deformations are allowed.

Vortex shedding around circular cylinders is a well known and studied phenomenon that appears in many engineering fields. In this work a Reduced Order Model (ROM) of the incompressible flow around a circular cylinder, built performing a Galerkin projection of the governing equations onto a lower dimensional space is presented. The reduced basis space is generated using a Proper Orthogonal Decomposition (POD) approach. In particular the focus is into (i) the correct reproduction of the pressure field, that in case of the vortex shedding phenomenon, is of primary importance for the calculation of the drag and lift coefficients; (ii) for this purpose the projection of the Governing equations (momentum equation and Poisson equation for pressure) is performed onto different reduced basis space for velocity and pressure, respectively; (iii) all the relevant modifications necessary to adapt standard finite element POD-Galerkin methods to a finite volume framework are presented. The accuracy of the reduced order model is assessed against full order results.

%B Communication in Applied Industrial Mathematics %G eng %U https://arxiv.org/abs/1701.03424 %9 reviewed %0 Report %D 2017 %T Almost global existence of solutions for capillarity-gravity water waves equations with periodic spatial boundary conditions %A Massimiliano Berti %A Jean-Marc Delort %X The goal of this monograph is to prove that any solution of the Cauchy problem for the capillarity-gravity water waves equations, in one space dimension, with periodic, even in space, initial data of small size ϵ, is almost globally defined in time on Sobolev spaces, i.e. it exists on a time interval of length of magnitude ϵ−N for any N, as soon as the initial data are smooth enough, and the gravity-capillarity parameters are taken outside an exceptional subset of zero measure. In contrast to the many results known for these equations on the real line, with decaying Cauchy data, one cannot make use of dispersive properties of the linear flow. Instead, our method is based on a normal forms procedure, in order to eliminate those contributions to the Sobolev energy that are of lower degree of homogeneity in the solution. Since the water waves equations are a quasi-linear system, usual normal forms approaches would face the well known problem of losses of derivatives in the unbounded transformations. In this monograph, to overcome such a difficulty, after a paralinearization of the capillarity-gravity water waves equations, necessary to obtain energy estimates, and thus local existence of the solutions, we first perform several paradifferential reductions of the equations to obtain a diagonal system with constant coefficients symbols, up to smoothing remainders. Then we may start with a normal form procedure where the small divisors are compensated by the previous paradifferential regularization.The reversible structure of the water waves equations, and the fact that we look for solutions even in x, guarantees a key cancellation which prevents the growth of the Sobolev norms of the solutions. %G en %U http://preprints.sissa.it/handle/1963/35285 %1 35590 %2 Mathematics %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2017-05-30T09:17:49Z No. of bitstreams: 1 1702.04674.pdf: 2311619 bytes, checksum: 0765035340f77780899e30e93390092b (MD5) %0 Report %D 2017 %T Analysis of a dynamic peeling test with speed-dependent toughness %A Giuliano Lazzaroni %A Lorenzo Nardini %X We analyse a one-dimensional model of dynamic debonding for a thin film, where the local toughness of the glue between the film and the substrate also depends on the debonding speed. The wave equation on the debonded region is strongly coupled with Griffth's criterion for the evolution of the debonding front. We provide an existence and uniqueness result and find explicitly the solution in some concrete examples. We study the limit of solutions as inertia tends to zero, observing phases of unstable propagation, as well as time discontinuities, even though the toughness diverges at a limiting debonding speed. %G en %U http://preprints.sissa.it/handle/1963/35292 %1 35598 %2 Mathematics %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2017-09-04T06:35:59Z No. of bitstreams: 1 Laz-Nar-17-speed-dependent-preprint.pdf: 361821 bytes, checksum: 40d65a6783f2e9ce4cb63b195a71a946 (MD5) %0 Journal Article %J Journal of Scientific Computing %D 2017 %T On the Application of Reduced Basis Methods to Bifurcation Problems in Incompressible Fluid Dynamics %A Giuseppe Pitton %A Gianluigi Rozza %XIn this paper we apply a reduced basis framework for the computation of flow bifurcation (and stability) problems in fluid dynamics. The proposed method aims at reducing the complexity and the computational time required for the construction of bifurcation and stability diagrams. The method is quite general since it can in principle be specialized to a wide class of nonlinear problems, but in this work we focus on an application in incompressible fluid dynamics at low Reynolds numbers. The validation of the reduced order model with the full order computation for a benchmark cavity flow problem is promising.

%B Journal of Scientific Computing %G eng %R 10.1007/s10915-017-0419-6 %0 Book Section %B Spectral and High Order Methods for Partial Differential Equations %D 2017 %T Certified Reduced Basis Method for Affinely Parametric Isogeometric Analysis NURBS Approximation %A Devaud, Denis %A Gianluigi Rozza %XIn this work we apply reduced basis methods for parametric PDEs to an isogeometric formulation based on

NURBS. The motivation for this work is an integrated and complete work pipeline from CAD to parametrization

of domain geometry, then from full order to certified reduced basis solution. IsoGeometric Analysis

(IGA) is a growing research theme in scientic computing and computational mechanics, as well as reduced

basis methods for parametric PDEs. Their combination enhances the solution of some class of problems,

especially the ones characterized by parametrized geometries we introduced in this work. For a general

overview on Reduced Basis (RB) methods we recall [7, 15] and on IGA [3]. This work wants to demonstrate

that it is also possible for some class of problems to deal with ane geometrical parametrization combined

with a NURBS IGA formulation. This is what this work brings as original ingredients with respect to other

works dealing with reduced order methods and IGA (set in a non-affine formulation, and using a POD [2]

sampling without certication: see for example for potential flows [12] and for Stokes flows [17]). In this work

we show a certication of accuracy and a complete integration between IGA formulation and parametric

certified greedy RB formulation. Section 2 recalls the abstract setting for parametrized PDEs, Section 3

recalls IGA setting, Section 4 deals with RB formulation, and Section 5 illustrates two numerical examples in heat transfer with different parametrization.

%B Spectral and High Order Methods for Partial Differential Equations %7 Bittencourt, Dumont, Hesthaven. (Eds). %I Springer %C Heildeberg %V 119 %@ 978-3-319-65869-8 %G eng %0 Journal Article %J SIAM Journal on Numerical Analysis %D 2017 %T On a certified smagorinsky reduced basis turbulence model %A Rebollo, T.C. %A Ávila, E.D. %A Marmol, M.G. %A Francesco Ballarin %A Gianluigi Rozza %B SIAM Journal on Numerical Analysis %V 55 %P 3047-3067 %G eng %U https://www.scopus.com/inward/record.uri?eid=2-s2.0-85039928218&doi=10.1137%2f17M1118233&partnerID=40&md5=221d9cd2bcc74121fcef93efd9d3d76c %R 10.1137/17M1118233 %0 Report %D 2017 %T Complex Friedrichs systems and applications %A Nenad Antonić %A Krešimir Burazin %A Ivana Crnjac %A Marko Erceg %X We provide a suitable extension of the theory of abstract Friedrichs systems from real Hilbert spaces to the complex Hilbert space setting, which allows for applications to partial differential equations with complex coeffcients. We also provide examples where the involved Hilbert space is not the space of square integrable functions, as it was the case in previous works, but rather its closed subspace or the space Hs(Rd;Cr), for real s. This setting appears to be suitable for particular systems of partial differential equations, such as the Dirac system, the Dirac-Klein-Gordon system, the Dirac-Maxwell system, and the time-harmonic Maxwell system, which are all addressed in the paper. Moreover, for the time-harmonic Maxwell system we also applied a suitable version of the two-field theory with partial coercivity assumption which is developed in the paper. %G en %U http://urania.sissa.it/xmlui/handle/1963/35270 %1 35576 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2017-01-20T12:35:16Z No. of bitstreams: 1 antonic_burazin_crnjac_erceg2016_preprint.pdf: 308035 bytes, checksum: 7c8e2264f51ab9699c6cbe9585fc047a (MD5) %0 Journal Article %J Journal of Computational Physics %D 2017 %T Computational reduction strategies for the detection of steady bifurcations in incompressible fluid-dynamics: Applications to Coanda effect in cardiology %A Giuseppe Pitton %A Annalisa Quaini %A Gianluigi Rozza %K Parametrized Navier–Stokes equations %K Reduced basis method %K Stability of flows %K Symmetry breaking bifurcation %XWe focus on reducing the computational costs associated with the hydrodynamic stability of solutions of the incompressible Navier–Stokes equations for a Newtonian and viscous fluid in contraction–expansion channels. In particular, we are interested in studying steady bifurcations, occurring when non-unique stable solutions appear as physical and/or geometric control parameters are varied. The formulation of the stability problem requires solving an eigenvalue problem for a partial differential operator. An alternative to this approach is the direct simulation of the flow to characterize the asymptotic behavior of the solution. Both approaches can be extremely expensive in terms of computational time. We propose to apply Reduced Order Modeling (ROM) techniques to reduce the demanding computational costs associated with the detection of a type of steady bifurcations in fluid dynamics. The application that motivated the present study is the onset of asymmetries (i.e., symmetry breaking bifurcation) in blood flow through a regurgitant mitral valve, depending on the Reynolds number and the regurgitant mitral valve orifice shape.

We prove in a direct, geometric way that for any compatible Riemannian metric on a Lie manifold the injectivity radius is positive

%B ArXiv e-prints %G eng %U https://arxiv.org/pdf/1707.07595.pdf %0 Journal Article %J ArXiv e-prints %D 2017 %T Integrable lifts for transitive Lie algebroids %A Androulidakis, I. %A Antonini, P. %K 14F40 %K 58H05 %K Mathematics - Differential Geometry %XInspired by the work of Molino, we show that the integrability obstruction for transitive Lie algebroids can be made to vanish by adding extra dimensions. In particular, we prove that the Weinstein groupoid of a non-integrable transitive and abelian Lie algebroid, is the quotient of a finite dimensional Lie groupoid. Two constructions as such are given: First, explaining the counterexample to integrability given by Almeida and Molino, we see that it can be generalized to the construction of an "Almeida-Molino" integrable lift when the base manifold is simply connected. On the other hand, we notice that the classical de Rham isomorphism provides a universal integrable algebroid. Using it we construct a "de Rham" integrable lift for any given transitive Abelian Lie algebroid.

%B ArXiv e-prints %G eng %U https://arxiv.org/pdf/1707.04855.pdf %0 Report %D 2017 %T Isomonodromy Deformations at an Irregular Singularity with Coalescing Eigenvalues %A Giordano Cotti %A Boris Dubrovin %A Davide Guzzetti %X We consider an n×n linear system of ODEs with an irregular singularity of Poincar\'e rank 1 at z=∞, holomorphically depending on parameter t within a polydisc in Cn centred at t=0. The eigenvalues of the leading matrix at z=∞ coalesce along a locus Δ contained in the polydisc, passing through t=0. Namely, z=∞ is a resonant irregular singularity for t∈Δ. We analyse the case when the leading matrix remains diagonalisable at Δ. We discuss the existence of fundamental matrix solutions, their asymptotics, Stokes phenomenon and monodromy data as t varies in the polydisc, and their limits for t tending to points of Δ. When the deformation is isomonodromic away from Δ, it is well known that a fundamental matrix solution has singularities at Δ. When the system also has a Fuchsian singularity at z=0, we show under minimal vanishing conditions on the residue matrix at z=0 that isomonodromic deformations can be extended to the whole polydisc, including Δ, in such a way that the fundamental matrix solutions and the constant monodromy data are well defined in the whole polydisc. These data can be computed just by considering the system at fixed t=0. Conversely, if the t-dependent system is isomonodromic in a small domain contained in the polydisc not intersecting Δ, if the entries of the Stokes matrices with indices corresponding to coalescing eigenvalues vanish, then we show that Δ is not a branching locus for the fundamental matrix solutions. The importance of these results for the analytic theory of Frobenius Manifolds is explained. An application to Painlev\'e equations is discussed. %G en %U http://preprints.sissa.it/handle/1963/35289 %1 35595 %2 Mathematics %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2017-06-23T06:17:29Z No. of bitstreams: 1 1706.04808.pdf: 1580637 bytes, checksum: da3f8ec8e58ca79a48489ce160bff70b (MD5) %0 Report %D 2017 %T Krein-Visik-Birman self-adjoint extension theory revisited %A Matteo Gallone %A Alessandro Michelangeli %A Andrea Ottolini %X The core results of the so-called KreIn-Visik-Birman theory of self-adjoint extensions of semi-bounded symmetric operators are reproduced, both in their original and in a more modern formulation, within a comprehensive discussion that includes missing details, elucidative steps, and intermediate results of independent interest. %G en %U http://preprints.sissa.it/handle/1963/35286 %1 35591 %2 Mathematics %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2017-05-31T08:18:47Z No. of bitstreams: 1 Gallone-Michelangeli-Ottolini-KVB.pdf: 675862 bytes, checksum: 325168fcaae89a9faedde0e5c32e69a7 (MD5) %0 Report %D 2017 %T A Lagrangian approach for scalar multi-d conservation laws %A Stefano Bianchini %A Paolo Bonicatto %A Elio Marconi %G en %U http://preprints.sissa.it/handle/1963/35290 %1 35596 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2017-08-08T08:57:31Z No. of bitstreams: 1 main.pdf: 427188 bytes, checksum: 8ab383e6ab2a6dcbf06a22d007db5dda (MD5) %0 Report %D 2017 %T Linear hyperbolic systems in domains with growing cracks %A Maicol Caponi %X We consider the hyperbolic system $\ddot u-{\rm div}\,(\mathbb A\nabla u)=f$ in the time varying cracked domain $\Omega\setminus\Gamma_t$, where the set $\Omega\subset\mathbb R^d$ is open, bounded, and with Lipschitz boundary, the cracks $\Gamma_t$, $t\in[0,T]$, are closed subsets of $\overline\Omega$, increasing with respect to inclusion, and $u(t):\Omega\setminus\Gamma_t\to\mathbb R^d$ for every $t\in[0,T]$. We assume the existence of suitable regular changes of variables, which reduce our problem to the transformed system $\ddot v-{\rm div}\,(\mathbb B\nabla v)+\mathbf a\nabla v -2\nabla\dot vb=g$ on the fixed domain $\Omega\setminus\Gamma_0$. Under these assumptions, we obtain existence and uniqueness of weak solutions for these two problems. Moreover, we show an energy equality for the functions $v$, which allows us to prove a continuous dependence result for both systems. %G en %U http://urania.sissa.it/xmlui/handle/1963/35271 %1 35577 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2017-01-30T11:26:46Z No. of bitstreams: 1 Caponi_LinHypSys.pdf: 432435 bytes, checksum: 3b798b4c79150cf0087bc6176258ffc6 (MD5) %0 Report %D 2017 %T Linearisation of multiwell energies %A Roberto Alicandro %A Gianni Dal Maso %A Giuliano Lazzaroni %A Mariapia Palombaro %X Linear elasticity can be rigorously derived from finite elasticity under the assumption of small loadings in terms of Gamma-convergence. This was first done in the case of one-well energies with super-quadratic growth and later generalised to different settings, in particular to the case of multi-well energies where the distance between the wells is very small (comparable to the size of the load). In this paper we study the case when the distance between the wells is independent of the size of the load. In this context linear elasticity can be derived by adding to the multi-well energy a singular higher order term which penalises jumps from one well to another. The size of the singular term has to satisfy certain scaling assumptions whose optimality is shown in most of the cases. Finally, the derivation of linear elasticty from a two-well discrete model is provided, showing that the role of the singular perturbation term is played in this setting by interactions beyond nearest neighbours. %G en %U http://preprints.sissa.it/handle/1963/35288 %1 35594 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2017-06-22T09:07:10Z No. of bitstreams: 1 ADMLP_linear.pdf: 364014 bytes, checksum: 305b4dcf6f1ee7c09e6747b7378ae58c (MD5) %0 Report %D 2017 %T Lp-boundedness of wave operators for the three-dimensional multi-centre point interaction %A Gianfausto Dell'Antonio %A Alessandro Michelangeli %A Raffaele Scandone %A Kenji Yajima %X We prove that, for arbitrary centres and strengths, the wave operators for three dimensional Schrödinger operators with multi-centre local point interactions are bounded in Lp(R3) for 1 < p < 3 and unbounded otherwise. %G en %U http://preprints.sissa.it/handle/1963/35283 %1 35588 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2017-04-13T11:49:31Z No. of bitstreams: 1 SISSA_preprint_70-2016-MATE.pdf: 474753 bytes, checksum: 846b3df07e7de2eb34c3371b0b1f835b (MD5) %0 Journal Article %J Biomechanics and Modeling in Mechanobiology %D 2017 %T Numerical modeling of hemodynamics scenarios of patient-specific coronary artery bypass grafts %A Ballarin, F. %A Faggiano, E. %A Manzoni, A. %A Quarteroni, A. %A Gianluigi Rozza %A Ippolito, S. %A Antona, C. %A Scrofani, R. %B Biomechanics and Modeling in Mechanobiology %V 16 %P 1373-1399 %G eng %U https://www.scopus.com/inward/record.uri?eid=2-s2.0-85015065851&doi=10.1007%2fs10237-017-0893-7&partnerID=40&md5=c388f20bd5de14187bad9ed7d9affbd0 %R 10.1007/s10237-017-0893-7 %0 Journal Article %J Communications in Applied and Industrial Mathematics %D 2017 %T POD-Galerkin reduced order methods for CFD using Finite Volume Discretisation: vortex shedding around a circular cylinder %A Giovanni Stabile %A Saddam Hijazi %A Andrea Mola %A Stefano Lorenzi %A Gianluigi Rozza %B Communications in Applied and Industrial Mathematics %I Walter de Gruyter {GmbH} %V 8 %P 210–236 %8 dec %G eng %U https://doi.org/10.1515/caim-2017-0011 %R 10.1515/caim-2017-0011 %0 Journal Article %J Communications in Applied and Industrial Mathematics %D 2017 %T POD-Galerkin reduced order methods for CFD using Finite Volume Discretisation: vortex shedding around a circular cylinder %A Stabile, Giovanni %A Hijazi, Saddam %A Mola, Andrea %A Lorenzi, Stefano %A Gianluigi Rozza %B Communications in Applied and Industrial Mathematics %V 8 %P 210-236 %G eng %R 10.1515/caim-2017-0011 %0 Journal Article %J SIAM/ASA Journal on Uncertainty Quantification %D 2017 %T Reduced Basis Methods for Uncertainty Quantification %A Peng Chen %A Alfio Quarteroni %A Gianluigi Rozza %XIn this work we review a reduced basis method for the solution of uncertainty quantification problems. Based on the basic setting of an elliptic partial differential equation with random input, we introduce the key ingredients of the reduced basis method, including proper orthogonal decomposition and greedy algorithms for the construction of the reduced basis functions, a priori and a posteriori error estimates for the reduced basis approximations, as well as its computational advantages and weaknesses in comparison with a stochastic collocation method [I. Babuška, F. Nobile, and R. Tempone, *SIAM Rev.*, 52 (2010), pp. 317--355]. We demonstrate its computational efficiency and accuracy for a benchmark problem with parameters ranging from a few to a few hundred dimensions. Generalizations to more complex models and applications to uncertainty quantification problems in risk prediction, evaluation of statistical moments, Bayesian inversion, and optimal control under uncertainty are also presented to illustrate how to use the reduced basis method in practice. Further challenges, advancements, and research opportunities are outlined.

Read More: http://epubs.siam.org/doi/abs/10.1137/151004550

In this work, two approaches, based on the certified Reduced Basis method, have been developed for simulating the movement of nuclear reactor control rods, in time-dependent non-coercive settings featuring a 3D geometrical framework. In particular, in a first approach, a piece-wise affine transformation based on subdomains division has been implemented for modelling the movement of one control rod. In the second approach, a “staircase” strategy has been adopted for simulating the movement of all the three rods featured by the nuclear reactor chosen as case study. The neutron kinetics has been modelled according to the so-called multi-group neutron diffusion, which, in the present case, is a set of ten coupled parametrized parabolic equations (two energy groups for the neutron flux, and eight for the precursors). Both the reduced order models, developed according to the two approaches, provided a very good accuracy compared with high-fidelity results, assumed as “truth” solutions. At the same time, the computational speed-up in the Online phase, with respect to the fine “truth” finite element discretization, achievable by both the proposed approaches is at least of three orders of magnitude, allowing a real-time simulation of the rod movement and control.

%B Communications in Computational Physics %I SISSA %8 2016 %G en %U http://urania.sissa.it/xmlui/handle/1963/34963 %N in press %1 35188 %2 Mathematics %$ Submitted by Gianluigi Rozza (grozza@sissa.it) on 2015-11-05T15:06:51Z No. of bitstreams: 1 manuscript.pdf: 2056729 bytes, checksum: 2a2fad22dc931e8c4094642e21c479cd (MD5) %0 Journal Article %J Computers and Mathematics with Applications %D 2016 %T Reduced basis method and domain decomposition for elliptic problems in networks and complex parametrized geometries %A Laura Iapichino %A Alfio Quarteroni %A Gianluigi Rozza %X The aim of this work is to solve parametrized partial differential equations in computational domains represented by networks of repetitive geometries by combining reduced basis and domain decomposition techniques. The main idea behind this approach is to compute once, locally and for few reference shapes, some representative finite element solutions for different values of the parameters and with a set of different suitable boundary conditions on the boundaries: these functions will represent the basis of a reduced space where the global solution is sought for. The continuity of the latter is assured by a classical domain decomposition approach. Test results on Poisson problem show the flexibility of the proposed method in which accuracy and computational time may be tuned by varying the number of reduced basis functions employed, or the set of boundary conditions used for defining locally the basis functions. The proposed approach simplifies the pre-computation of the reduced basis space by splitting the global problem into smaller local subproblems. Thanks to this feature, it allows dealing with arbitrarily complex network and features more flexibility than a classical global reduced basis approximation where the topology of the geometry is fixed. %B Computers and Mathematics with Applications %I Elsevier %V 71 %P 430 %8 01/2016 %G en %N 1 %1 35187 %2 Mathematics %4 1 %# MAT/08 %$ Submitted by Gianluigi Rozza (grozza@sissa.it) on 2015-11-05T14:59:46Z No. of bitstreams: 1 RDF2_reduced.pdf: 3254431 bytes, checksum: 508b8775e27dfb868f1b39c270cb4a6f (MD5) %& 408 %0 Report %D 2016 %T Reduced-order semi-implicit schemes for fluid-structure interaction problems %A Francesco Ballarin %A Gianluigi Rozza %A Yvon Maday %B Special Volume MoRePaS %8 11/2016 %G eng %9 book chapter %0 Report %D 2016 %T Second-order structured deformations %A Ana Cristina Barroso %A Jose Matias %A Marco Morandotti %A David R. Owen %I SISSA %G en %1 35497 %2 Mathematics %4 1 %$ Submitted by Lucio Lubiana (lubiana@sissa.it) on 2016-07-08T11:42:55Z No. of bitstreams: 1 Morandott-2oStD.pdf: 385787 bytes, checksum: 31ae44cb708c09f82aba2f6ea5e73248 (MD5) %0 Conference Paper %B The 26th International Ocean and Polar Engineering Conference %D 2016 %T Ship Sinkage and Trim Predictions Based on a CAD Interfaced Fully Nonlinear Potential Model %A Mola, Andrea %A Heltai, Luca %A Desimone, Antonio %A others %B The 26th International Ocean and Polar Engineering Conference %I International Society of Offshore and Polar Engineers %V 3 %P 511–518 %G eng %0 Thesis %D 2016 %T Some results on quasistatic evolution problems for unidirectional processes %A Vito Crismale %I SISSA %G en %1 35522 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by vcrisma@sissa.it (vcrisma@sissa.it) on 2016-09-18T20:26:55Z No. of bitstreams: 1 TesiPHD.pdf: 1721272 bytes, checksum: 95ef69bafc860616d3cdb08901da7ffb (MD5) %0 Thesis %D 2016 %T Some results on the mathematical analysis of crack problems with forces applied on the fracture lips %A Stefano Almi %K Fracture mechanics %X This thesis is devoted to the study of some models of fracture growth in elastic materials, characterized by the presence of forces acting on the crack lips. Working in the general framework of rate-independent processes, we first discuss a variational formulation of the problem of quasi-static crack evolution in hydraulic fracture. Then, we investigate the crack growth process in a cohesive fracture model, showing the existence of an evolution satisfying a weak Griffith's criterion. Finally, in the last chapter of this work we investigate, in the static case, the interaction between the energy spent in order to create a new fracture and the energy spent by the applied surface forces. This leads us to study the lower semicontinuity properties of a free discontinuity functional F(u) that can be written as the sum of a crack term, depending on the jump set of u, and of a boundary term, depending on the trace of u. %I SISSA %G en %1 35503 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by salmi@sissa.it (salmi@sissa.it) on 2016-08-09T10:34:01Z No. of bitstreams: 1 Almi-PhDThesis.pdf: 2060635 bytes, checksum: 5fab9efd5312430a0c9e57282df75694 (MD5) %0 Report %D 2016 %T On the structure of $L^\infty$-entropy solutions to scalar conservation laws in one-space dimension %A Stefano Bianchini %A Elio Marconi %X We prove that if $u$ is the entropy solution to a scalar conservation law in one space dimension, then the entropy dissipation is a measure concentrated on countably many Lipschitz curves. This result is a consequence of a detailed analysis of the structure of the characteristics. In particular the characteristic curves are segments outside a countably 1-rectifiable set and the left and right traces of the solution exist in a $C^0$-sense up to the degeneracy due to the segments where $f''=0$. We prove also that the initial data is taken in a suitably strong sense and we give some counterexamples which show that these results are sharp. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/35209 %1 35508 %2 Mathematics %# MAT/05 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2016-09-06T09:18:03Z No. of bitstreams: 1 1608.02811v1.pdf: 591028 bytes, checksum: 069b218b01f350df6db7904e245ef701 (MD5) %0 Journal Article %J Correggi, M., Dimonte, D., 2016. On the third critical speed for rotating Bose-Einstein condensates. J. Math. Phys. 57, 71901 %D 2016 %T On the third critical speed for rotating Bose-Einstein condensates %A Daniele Dimonte %A Michele Correggi %X We study a two-dimensional rotating Bose-Einstein condensate confined by an anharmonic trap in the framework of the Gross-Pitaevskii theory. We consider a rapid rotation regime close to the transition to a giant vortex state. It was proven in Correggi et al. [J. Math. Phys. 53, 095203 (2012)] that such a transition occurs when the angular velocity is of order ε−4, with ε−2 denoting the coefficient of the nonlinear term in the Gross-Pitaevskii functional and ε ≪ 1 (Thomas-Fermi regime). In this paper, we identify a finite value Ωc such that if Ω = Ω0/ε4 with Ω0 > Ωc, the condensate is in the giant vortex phase. Under the same condition, we prove a refined energy asymptotics and an estimate of the winding number of any Gross-Pitaevskii minimizer. %B Correggi, M., Dimonte, D., 2016. On the third critical speed for rotating Bose-Einstein condensates. J. Math. Phys. 57, 71901 %I AIP Publisher %G en %U http://urania.sissa.it/xmlui/handle/1963/35246 %1 35557 %2 Mathematics %$ Submitted by ddimonte@sissa.it (ddimonte@sissa.it) on 2016-10-19T16:34:31Z No. of bitstreams: 1 1508.07235v4.pdf: 520340 bytes, checksum: e987bbeef8fe09e31b8ea970c4ae4b4b (MD5) %R 10.1063/1.4954805 %0 Thesis %D 2016 %T t-structures on stable (infinity,1)-categories %A Fosco Loregian %K category theory, higher category theory, factorization system, torsion theory, homological algebra, higher algebra %X The present work re-enacts the classical theory of t-structures reducing the classical definition coming from Algebraic Geometry to a rather primitive categorical gadget: suitable reflective factorization systems (defined in the work of Rosický, Tholen, and Cassidy-Hébert-Kelly), which we call "normal torsion theories" following. A relation between these two objects has previously been noticed by other authors, on the level of the triangulated homotopy categories of stable (infinity,1)-categories. The main achievement of the present thesis is to observe and prove that this relation exists genuinely when the definition is lifted to the higher-dimensional world where the notion of triangulated category comes from. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/35202 %1 35477 %2 Mathematics %4 1 %# MAT/03 %$ Submitted by floregi@sissa.it (floregi@sissa.it) on 2016-06-10T18:05:18Z No. of bitstreams: 1 main-w.pdf: 1321458 bytes, checksum: b705aee6a0652769f8d48ad2ec750e94 (MD5) %0 Thesis %D 2016 %T Two explorations in Dynamical Systems and Mechanics %A Paolo Gidoni %K Poincaré-Birkhoff Theorem %X This thesis contains the work done by Paolo Gidoni during the doctorate programme in Matematical Analysis at SISSA, under the supervision of A. Fonda and A. DeSimone. The thesis is composed of two parts: "Avoiding cones conditions and higher dimensional twist" and "Directional friction in bio-inspired locomotion". %I SISSA %G en %1 35527 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by Paolo Gidoni (pgidoni@sissa.it) on 2016-09-27T15:43:47Z No. of bitstreams: 1 PaoloGidoniDissertation.pdf: 3516967 bytes, checksum: 7ba7e59fb23b28fdd3ca2a95796a5827 (MD5) %0 Journal Article %D 2015 %T Anisotropic mean curvature on facets and relations with capillarity %A Stefano Amato %A Lucia Tealdi %A Giovanni Bellettini %X We discuss the relations between the anisotropic calibrability of a facet F of a solid crystal E, and the capillary problem on a capillary tube with base F. When F is parallel to a facet of the Wulff shape, calibrability is equivalent to show the existence of an anisotropic subunitary vector field in $F, with suitable normal trace on the boundary of the facet, and with constant divergence equal to the anisotropic mean curvature of F. When the Wulff shape is a cylynder, assuming E convex at F, and F (strictly) calibrable, such a vector field is obtained by solving the capillary problem on F in absence of gravity and with zero contact angle. We show some examples of facets for which it is possible, even without the strict calibrability assumption, to build one of these vector fields. The construction provides, at least for convex facets of class C^{1,1}, the solution of the total variation flow starting at 1_F. %I de Gruyter %G en_US %U http://urania.sissa.it/xmlui/handle/1963/34481 %1 34663 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by Stefano Amato (samato@sissa.it) on 2015-08-06T08:33:21Z No. of bitstreams: 1 amato_bellettini_tealdi.pdf: 561517 bytes, checksum: ee2370b8b8ae04078e1e8eae84d37bdd (MD5) %R 10.1515/geofl-2015-0005 %0 Journal Article %J Computers and Mathematics with Applications 69 (2015) 1167–1188 %D 2015 %T Benchmarking the Immersed Finite Element Method for Fluid-Structure Interaction Problems %A Roy Saswati %A Luca Heltai %A Francesco Costanzo %X We present an implementation of a fully variational formulation of an immersed methods for fluid-structure interaction problems based on the finite element method. While typical implementation of immersed methods are characterized by the use of approximate Dirac delta distributions, fully variational formulations of the method do not require the use of said distributions. In our implementation the immersed solid is general in the sense that it is not required to have the same mass density and the same viscous response as the surrounding fluid. We assume that the immersed solid can be either viscoelastic of differential type or hyperelastic. Here we focus on the validation of the method via various benchmarks for fluid-structure interaction numerical schemes. This is the first time that the interaction of purely elastic compressible solids and an incompressible fluid is approached via an immersed method allowing a direct comparison with established benchmarks. %B Computers and Mathematics with Applications 69 (2015) 1167–1188 %G en %1 34633 %2 Mathematics %4 1 %# MAT/08 %$ Submitted by Luca Heltai (heltai@sissa.it) on 2015-04-20T15:26:58Z No. of bitstreams: 1 rhc_feibm_validation-v3.pdf: 7039131 bytes, checksum: 705f28e17037504f00766fc4e84a10a4 (MD5) %R 10.1016/j.camwa.2015.03.012 %0 Report %D 2015 %T A bridging mechanism in the homogenisation of brittle composites with soft inclusions %A Marco Barchiesi %A Giuliano Lazzaroni %A Caterina Ida Zeppieri %X We provide a homogenisation result for the energy-functional associated with a purely brittle composite whose microstructure is characterised by soft periodic inclusions embedded in a stiffer matrix. We show that the two constituents as above can be suitably arranged on a microscopic scale ε to obtain, in the limit as ε tends to zero, a homogeneous macroscopic energy-functional explicitly depending on the opening of the crack. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/7492 %1 7621 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-01-26T14:21:23Z No. of bitstreams: 1 BarLazZep-soft-2015(1).pdf: 488285 bytes, checksum: 252f196c34b0c22b00f3de1f36190176 (MD5) %0 Book %B Springer Briefs in Mathematics %D 2015 %T Certified Reduced Basis Methods for Parametrized Partial Differential Equations %A Jan S Hesthaven %A Gianluigi Rozza %A Benjamin Stamm %K a posteriori error bounds %K empirical interpolation %K parametrized partial differential equations %K reduced basis methods, greedy algorithms %XThis book provides a thorough introduction to the mathematical and algorithmic aspects of certified reduced basis methods for parametrized partial differential equations. Central aspects ranging from model construction, error estimation and computational efficiency to empirical interpolation methods are discussed in detail for coercive problems. More advanced aspects associated with time-dependent problems, non-compliant and non-coercive problems and applications with geometric variation are also discussed as examples.

%B Springer Briefs in Mathematics %7 1 %I Springer %C Switzerland %P 135 %@ 978-3-319-22469-5 %G eng %6 1 %0 Report %D 2015 %T A class of Hamiltonians for a three-particle fermionic system at unitarity %A Michele Correggi %A Gianfausto Dell'Antonio %A Domenico Finco %A Alessandro Michelangeli %A Alessandro Teta %X We consider a quantum mechanical three-particle system made of two identical fermions of mass one and a different particle of mass $m$, where each fermion interacts via a zero-range force with the different particle. In particular we study the unitary regime, i.e., the case of infinite two-body scattering length. The Hamiltonians describing the system are, by definition, self-adjoint extensions of the free Hamiltonian restricted on smooth functions vanishing at the two-body coincidence planes, i.e., where the positions of two interacting particles coincide. It is known that for $m$ larger than a critical value $m^* \simeq (13.607)^{-1}$ a self-adjoint and lower bounded Hamiltonian $H_0$ can be constructed, whose domain is characterized in terms of the standard point-interaction boundary condition at each coincidence plane. Here we prove that for $m\in(m^*,m^{**})$, where $m^{**}\simeq (8.62)^{-1}$, there is a further family of self-adjoint and lower bounded Hamiltonians $H_{0,\beta}$, $\beta \in \mathbb{R}$, describing the system. Using a quadratic form method, we give a rigorous construction of such Hamiltonians and we show that the elements of their domains satisfy a further boundary condition, characterizing the singular behavior when the positions of all the three particles coincide. %G en %U http://urania.sissa.it/xmlui/handle/1963/34469 %1 34644 %2 Mathematics %4 1 %$ Submitted by Alessandro Michelangeli (alemiche@sissa.it) on 2015-05-21T06:33:20Z No. of bitstreams: 1 SISSA_preprint_22-2015-MATE.pdf: 438261 bytes, checksum: ca05e5e2c5d78d87225a11073cb09d47 (MD5) %0 Report %D 2015 %T Convex combinations of low eigenvalues, Fraenkel asymmetries and attainable sets %A Dario Mazzoleni %A Davide Zucco %X We consider the problem of minimizing convex combinations of the first two eigenvalues of the Dirichlet-Laplacian among open set of $R^N$ of fixed measure. We show that, by purely elementary arguments, based on the minimality condition, it is possible to obtain informations on the geometry of the minimizers of convex combinations: we study, in particular, when these minimizers are no longer convex, and the optimality of balls. As an application of our results we study the boundary of the attainable set for the Dirichlet spectrum. Our techniques involve symmetry results à la Serrin, explicit constants in quantitative inequalities, as well as a purely geometrical problem: the minimization of the Fraenkel 2-asymmetry among convex sets of fixed measure. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/35140 %1 35378 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by Davide Zucco (dzucco@sissa.it) on 2015-12-03T12:26:59Z No. of bitstreams: 1 Mazzoleni_Zucco_preprint_SISSA.pdf: 437631 bytes, checksum: 990947c0f9a62d173c6e72d105297d19 (MD5) %0 Journal Article %D 2015 %T Deal2lkit: a Toolkit Library for High Performance Programming in deal.II %A Alberto Sartori %A Nicola Giuliani %A Mauro Bardelloni %A Luca Heltai %X We present version 1.0.0 of the deal2lkit (deal.II ToolKit) library. deal2lkit is a collection of modules and classes for the general purpose finite element library deal.II. Its principal aim is to provide a high level interface, controlled via parameter files, for those steps that are common in all finite element programs: mesh generation, selection of the finite element type, application of boundary conditions and many others. Each module can be used as a building block independently on the others, and can be integrated in existing finite element codes based on deal.II, drastically reducing the size of programs, rendering their use automatically parametrised, and reducing the overall time-to-market of finite element programming. Moreover, deal2lkit features interfaces with the SUNDIALS (SUite of Nonlinear and DIfferential/ALgebraic equation Solvers) and ASSIMP (Open Asset Import Library) libraries. Some examples are provided which show the aim and scopes of deal2lkit. The deal2lkit library is released under the GNU Lesser General Public License (LGPL) and can be retrieved from the deal2lkit repository https://github.com/mathLab/deal2lkit. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/35006 %1 35235 %2 Mathematics %4 1 %# MAT/08 %$ Submitted by asartori@sissa.it (asartori@sissa.it) on 2015-11-13T13:12:29Z No. of bitstreams: 1 paper_deal2lkit.pdf: 1085486 bytes, checksum: 1dc7e9b9790fe38d2ced7b5328633cd8 (MD5) %0 Journal Article %J Archive of Numerical Software, vol. 3, n. 100, (2015), pages : 1-8 %D 2015 %T The deal.II Library, Version 8.2 %A Wolfgang Bangerth %A Timo Heister %A Luca Heltai %A Guido Kanschat %A Martin Kronbichler %A Matthias Maier %A Bruno Turcksin %A Toby D. Young %X This paper provides an overview of the new features of the finite element library deal.II version 8.2 %B Archive of Numerical Software, vol. 3, n. 100, (2015), pages : 1-8 %G en %U http://urania.sissa.it/xmlui/handle/1963/34464 %1 34637 %2 Mathematics %4 1 %# MAT/08 %$ Submitted by Luca Heltai (heltai@sissa.it) on 2015-04-20T15:40:46Z No. of bitstreams: 1 18031-44567-1-PB (1).pdf: 137014 bytes, checksum: 9a5fddeccfa389c32ca89a466e653074 (MD5) %R 10.11588/ans.2015.100.18031 %0 Journal Article %D 2015 %T Dispersive deformations of the Hamiltonian structure of Euler's equations %A Matteo Casati %X Euler's equations for a two-dimensional system can be written in Hamiltonian form, where the Poisson bracket is the Lie-Poisson bracket associated to the Lie algebra of divergence free vector fields. We show how to derive the Poisson brackets of 2d hydrodynamics of ideal fluids as a reduction from the one associated to the full algebra of vector fields. Motivated by some recent results about the deformations of Lie-Poisson brackets of vector fields, we study the dispersive deformations of the Poisson brackets of Euler's equation and show that, up to the second order, they are trivial. %G en %1 34700 %2 Mathematics %4 1 %# MAT/07 %$ Submitted by Matteo Casati (mcasati@sissa.it) on 2015-09-09T13:27:08Z No. of bitstreams: 1 defoHD.pdf: 195202 bytes, checksum: 9ee41e73fc37dd79f1659dda2e742b57 (MD5) %0 Report %D 2015 %T Dynamics of screw dislocations: a generalised minimising-movements scheme approach %A Giovanni A. Bonaschi %A Patrick Van Meurs %A Marco Morandotti %X The gradient flow structure of the model introduced in [CG99] for the dynamics of screw dislocations is investigated by means of a generalised minimising-movements scheme approach. The assumption of a finite number of available glide directions, together with the "maximal dissipation criterion" that governs the equations of motion, results into solving a differential inclusion rather than an ODE. This paper addresses how the model in [CG99] is connected to a time-discrete evolution scheme which explicitly confines dislocations to move each time step along a single glide direction. It is proved that the time-continuous model in [CG99] is the limit of these time-discrete minimising-movement schemes when the time step converges to 0. The study presented here is a first step towards a generalization of the setting in [AGS08, Chap. 2 and 3] that allows for dissipations which cannot be described by a metric. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/34495 %1 34692 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-09-04T08:36:59Z No. of bitstreams: 1 BvMM_03_9_15-MM.pdf: 773084 bytes, checksum: 686749d206d2f9c676ab004b860799f4 (MD5) %0 Report %D 2015 %T Existence for constrained dynamic Griffith fracture with a weak maximal dissipation condition %A Gianni Dal Maso %A Christopher J. Larsen %A Rodica Toader %X There are very few existence results for fracture evolution, outside of globally minimizing quasi-static evolutions. Dynamic evolutions are particularly problematic, due to the difficulty of showing energy balance, as well as of showing that solutions obey a maximal dissipation condition, or some similar condition that prevents stationary cracks from always being solutions. Here we introduce a new weak maximal dissipation condition and show that it is compatible with cracks constrained to grow smoothly on a smooth curve. In particular, we show existence of dynamic fracture evolutions satisfying this maximal dissipation condition, subject to the above smoothness constraints, and exhibit explicit examples to show that this maximal dissipation principle can indeed rule out stationary cracks as solutions. %G en %U http://urania.sissa.it/xmlui/handle/1963/35045 %1 35277 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by Gianni Dal Maso (dalmaso@sissa.it) on 2015-11-18T15:46:32Z No. of bitstreams: 1 DM-Lar-Toa-SISSA.pdf: 313034 bytes, checksum: 76419fd2c8c435ae7deeca773b424667 (MD5) %0 Journal Article %J Adv. Differential Equations 20 (2015), 937–982. %D 2015 %T Existence of positive solutions in the superlinear case via coincidence degree: the Neumann and the periodic boundary value problems %A Guglielmo Feltrin %A Fabio Zanolin %X We prove the existence of positive periodic solutions for the second order nonlinear equation u'' + a(x) g(u) = 0, where g(u) has superlinear growth at zero and at infinity. The weight function a(x) is allowed to change its sign. Necessary and sufficient conditions for the existence of nontrivial solutions are obtained. The proof is based on Mawhin's coincidence degree and applies also to Neumann boundary conditions. Applications are given to the search of positive solutions for a nonlinear PDE in annular domains and for a periodic problem associated to a non-Hamiltonian equation. %B Adv. Differential Equations 20 (2015), 937–982. %I Khayyam Publishing %G en %U http://projecteuclid.org/euclid.ade/1435064518 %1 35388 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-12-18T08:49:04Z No. of bitstreams: 1 FeltrinZanolin_ade2015.pdf: 321052 bytes, checksum: 38a45a1515a02fc86751b5f088bbfbfb (MD5) %0 Conference Paper %B International Conference on Parallel Processing and Applied Mathematics %D 2015 %T Experience on vectorizing lattice Boltzmann kernels for multi-and many-core architectures %A Calore, Enrico %A Demo, Nicola %A Schifano, Sebastiano Fabio %A Tripiccione, Raffaele %B International Conference on Parallel Processing and Applied Mathematics %I Springer %P 53–62 %G eng %0 Report %D 2015 %T Explicit formulas for relaxed disarrangement densities arising from structured deformations %A Ana Cristina Barroso %A Jose Matias %A Marco Morandotti %A David R. Owen %X Structured deformations provide a multiscale geometry that captures the contributions at the macrolevel of both smooth geometrical changes and non-smooth geometrical changes (disarrangements) at submacroscopic levels. For each (first-order) structured deformation (g,G) of a continuous body, the tensor field G is known to be a measure of deformations without disarrangements, and M:=∇g−G is known to be a measure of deformations due to disarrangements. The tensor fields G and M together deliver not only standard notions of plastic deformation, but M and its curl deliver the Burgers vector field associated with closed curves in the body and the dislocation density field used in describing geometrical changes in bodies with defects. Recently, Owen and Paroni [13] evaluated explicitly some relaxed energy densities arising in Choksi and Fonseca’s energetics of structured deformations [4] and thereby showed: (1) (trM)+ , the positive part of trM, is a volume density of disarrangements due to submacroscopic separations, (2) (trM)−, the negative part of trM, is a volume density of disarrangements due to submacroscopic switches and interpenetrations, and (3) trM, the absolute value of trM, is a volume density of all three of these non-tangential disarrangements: separations, switches, and interpenetrations. The main contribution of the present research is to show that a different approach to the energetics of structured deformations, that due to Ba\'{i}a, Matias, and Santos [1], confirms the roles of (trM)+, (trM)−, and trM established by Owen and Paroni. In doing so, we give an alternative, shorter proof of Owen and Paroni’s results, and we establish additional explicit formulas for other measures of disarrangements. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/34492 %1 34687 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-08-28T10:09:53Z No. of bitstreams: 1 SISSA_Preprint_37_2015_MATE.pdf: 315599 bytes, checksum: 2bd676c192205d3a2edd7c48bf53c11c (MD5) %0 Report %D 2015 %T Extended affine Weyl groups of BCD type, Frobenius manifolds and their Landau-Ginzburg superpotentials %A Boris Dubrovin %A Ian A.B. Strachan %A Youjin Zhang %A Dafeng Zuo %X For the root systems of type Bl, Cl and Dl, we generalize the result of [7] by showing the existence of Frobenius manifold structures on the orbit spaces of the extended affine Weyl groups that correspond to any vertex of the Dynkin diagram instead of a particular choice made in [7]. It also depends on certain additional data. We also construct LG superpotentials for these Frobenius manifold structures. %I SISSA %G en %U http://preprints.sissa.it/handle/1963/35316 %1 35625 %2 Mathematics %4 1 %# MAT/07 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2018-05-23T10:53:54Z No. of bitstreams: 1 1510.08690.pdf: 433692 bytes, checksum: 0cd6111d36bb3b57262400e1f1cebe3a (MD5) %0 Report %D 2015 %T Fast simulations of patient-specific haemodynamics of coronary artery bypass grafts based on a POD-Galerkin method and a vascular shape parametrization %A Francesco Ballarin %A Elena Faggiano %A Sonia Ippolito %A Andrea Manzoni %A Alfio Quarteroni %A Gianluigi Rozza %A Roberto Scrofani %X In this work a reduced-order computational framework for the study of haemodynamics in three-dimensional patient-specific configurations of coronary artery bypass grafts dealing with a wide range of scenarios is proposed. We combine several efficient algorithms to face at the same time both the geometrical complexity involved in the description of the vascular network and the huge computational cost entailed by time dependent patient-specific flow simulations. Medical imaging procedures allow to reconstruct patient-specific configurations from clinical data. A centerlines-based parametrization is proposed to efficiently handle geometrical variations. POD–Galerkin reduced-order models are employed to cut down large computational costs. This computational framework allows to characterize blood flows for different physical and geometrical variations relevant in the clinical practice, such as stenosis factors and anastomosis variations, in a rapid and reliable way. Several numerical results are discussed, highlighting the computational performance of the proposed framework, as well as its capability to perform sensitivity analysis studies, so far out of reach. %G en %U http://urania.sissa.it/xmlui/handle/1963/34623 %1 34824 %2 Mathematics %4 1 %# MAT/08 %$ Submitted by Gianluigi Rozza (grozza@sissa.it) on 2015-10-07T00:30:27Z No. of bitstreams: 1 REPORT.pdf: 10426315 bytes, checksum: 6e5ddf4eb4cacdc7e803c2db1a540fc9 (MD5) %0 Journal Article %J Engineering Analysis with Boundary Elements 59 (2015), pp. 8-22 %D 2015 %T FEM SUPG stabilisation of mixed isoparametric BEMs: application to linearised free surface flows %A Nicola Giuliani %A Andrea Mola %A Luca Heltai %A Luca Formaggia %X In finite element formulations, transport dominated problems are often stabilised through the Streamline-Upwind-Petrov–Galerkin (SUPG) method. Its application is straightforward when the problem at hand is solved using Galerkin methods. Applications of boundary integral formulations often resort to collocation techniques which are computationally more tractable. In this framework, the Galerkin method and the stabilisation may still be used to successfully apply boundary conditions and resolve instabilities that are frequently observed in transport dominated problems. We apply this technique to an adaptive collocation boundary element method for the solution of stationary potential flows, where we solve a mixed Poisson problem in boundary integral form, with the addition of linearised free surface boundary conditions. We use a mixed boundary element formulation to allow for different finite dimensional spaces describing the flow potential and its normal derivative, and we validate our method simulating the flow around both a submerged body and a surface piercing body. The coupling of mixed surface finite elements and strongly consistent stabilisation techniques with boundary elements opens up the possibility to use non conformal unstructured grids with local refinement, without introducing the inconsistencies of other stabilisation techniques based on up-winding and finite difference schemes. %B Engineering Analysis with Boundary Elements 59 (2015), pp. 8-22 %G en_US %U http://urania.sissa.it/xmlui/handle/1963/34466 %1 34640 %2 Mathematics %4 1 %# MAT/08 %$ Submitted by ngiuliani@sissa.it (ngiuliani@sissa.it) on 2015-05-04T12:32:04Z No. of bitstreams: 1 paper-free-surface.pdf: 888763 bytes, checksum: 68366266786e84b78a356acd6de50840 (MD5) %R 10.1016/j.enganabound.2015.04.006 %0 Journal Article %J Engineering Analysis with Boundary Elements %D 2015 %T FEM SUPG stabilisation of mixed isoparametric BEMs: application to linearised free surface flows %A Giuliani, Nicola %A Mola, Andrea %A Heltai, Luca %A Formaggia, Luca %B Engineering Analysis with Boundary Elements %V 8–22 %P 59 %G eng %0 Journal Article %D 2015 %T Generalizing the Poincaré-Miranda theorem: the avoiding cones condition %A Alessandro Fonda %A Paolo Gidoni %X After proposing a variant of the Poincaré-Bohl theorem, we extend the Poincaré-Miranda theorem in several directions, by introducing an avoiding cones condition. We are thus able to deal with functions defined on various types of convex domains, and situations where the topological degree may be different from ±1. An illustrative application is provided for the study of functionals having degenerate multi-saddle points. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/35173 %1 35455 %2 Mathematics %4 1 %# MAT/05 %$ Approved for entry into archive by Maria Pia Calandra (calapia@sissa.it) on 2016-02-18T12:53:46Z (GMT) No. of bitstreams: 0 %R 10.1007/s10231-015-0519-6 %0 Thesis %D 2015 %T Geometric phases in graphene and topological insulators %A Domenico Monaco %K Geometric phases, graphene, topological insulators, Wannier functions, Bloch frames %X This thesis collects three of the publications that the candidate produced during his Ph.D. studies. They all focus on geometric phases in solid state physics. We first study topological phases of 2-dimensional periodic quantum systems, in absence of a spectral gap, like e.g. (multilayer) graphene. A topological invariant n_v in Z, baptized eigenspace vorticity, is attached to any intersection of the energy bands, and characterizes the local topology of the eigenprojectors around that intersection. With the help of explicit models, each associated to a value of n_v in Z, we are able to extract the decay at infinity of the single-band Wannier function w in mono- and bilayer graphene, obtaining |w(x)| <= const |x|^{-2} as |x| tends to infinity. Next, we investigate gapped periodic quantum systems, in presence of time-reversal symmetry. When the time-reversal operator Theta is of bosonic type, i.e. it satisfies Theta^2 = 1, we provide an explicit algorithm to construct a frame of smooth, periodic and time-reversal symmetric (quasi-)Bloch functions, or equivalently a frame of almost-exponentially localized, real-valued (composite) Wannier functions, in dimension d <= 3. In the case instead of a fermionic time-reversal operator, satisfying Theta^2 = -1, we show that the existence of such a Bloch frame is in general topologically obstructed in dimension d=2 and d=3. This obstruction is encoded in Z_2-valued topological invariants, which agree with the ones proposed in the solid state literature by Fu, Kane and Mele. %I SISSA %G en %1 34702 %2 Mathematics %4 1 %# MAT/07 %$ Submitted by Domenico Monaco (dmonaco@sissa.it) on 2015-09-13T00:09:51Z No. of bitstreams: 1 Monaco_PhDThesis.pdf: 1801696 bytes, checksum: 83cdd0dee2cc65cb246735d92f21c74a (MD5) %0 Thesis %D 2015 %T Gibbs-Markov-Young Structures and Decay of Correlations %A Marks Ruziboev %K Decay of Correlations, GMY-towers %X In this work we study mixing properties of discrete dynamical systems and related to them geometric structure. In the first chapter we show that the direct product of maps with Young towers admits a Young tower whose return times decay at a rate which is bounded above by the slowest of the rates of decay of the return times of the component maps. An application of this result, together with other results in the literature, yields various statistical properties for the direct product of various classes of systems, including Lorenz-like maps, multimodal maps, piecewise $C^2$ interval maps with critical points and singularities, H\'enon maps and partially hyperbolic systems. The second chapter is dedicated to the problem of decay of correlations for continuous observables. First we show that if the underlying system admits Young tower then the rate of decay of correlations for continuous observables can be estimated in terms of modulus of continuity and the decay rate of tail of Young tower. In the rest of the second chapter we study the relations between the rates of decay of correlations for smooth observables and continuous observables. We show that if the rates of decay of correlations is known for $C^r,$ observables ($r\ge 1$) then it is possible to obtain decay of correlations for continuous observables in terms of modulus of continuity. %I SISSA %G en %1 34677 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by mruziboe@sissa.it (mruziboe@sissa.it) on 2015-08-10T16:44:24Z No. of bitstreams: 1 ruziboev_thesis.pdf: 745751 bytes, checksum: 7743d9fe13df739ad5fe5dd9a0eed202 (MD5) %0 Report %D 2015 %T Global well-posedness of the magnetic Hartree equation with non-Strichartz external fields %A Alessandro Michelangeli %X We study the magnetic Hartree equation with external fields to which magnetic Strichartz estimates are not necessarily applicable. We characterise the appropriate notion of energy space and in such a space we prove the global well-posedness of the associated initial value problem by means of energy methods only. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/34440 %1 34567 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-02-09T07:36:23Z No. of bitstreams: 1 SISSA_preprint_07-2015-MATE.pdf: 185909 bytes, checksum: ae723e94b4951f0092f096c72ebf14d6 (MD5) %0 Report %D 2015 %T Globally stable quasi static evolution for strain gradient plasticity coupled with damage %A Vito Crismale %X Abstract. Weconsiderevolutionsforamaterialmodelwhichcouplesscalardamage with strain gradient plasticity, in small strain assumptions. For strain gradient plasticity, we follow the Gurtin-Anand formulation [Gurtin-Anand 2005]. The aim of the present model is to account for different phenomena: on the one hand the elastic stiffness reduces and the plastic yield surface shrinks due to material’s degradation, on the other hand the dislocation density affects the damage growth. The main result of this paper is the existence of a globally stable quasistatic evolution (in the so- called energetic formulation). Furthermore we study the limit model as the strain gradient terms tend to zero. Under stronger regularity assumptions, we show that the evolutions converge to the ones for the coupled elastoplastic–damage model studied in [Crismale, 2014]. %G en_US %1 34652 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by vcrisma@sissa.it (vcrisma@sissa.it) on 2015-07-13T13:37:08Z No. of bitstreams: 1 GurtinAnand.pdf: 523014 bytes, checksum: ac4506a87d3e772cac01bf99aa86c342 (MD5) %0 Journal Article %D 2015 %T Hilbert schemes of points of OP1(-n) as quiver varieties %A Ugo Bruzzo %X Relying on a representation of framed torsion-free sheaves on Hirzebruch surfaces in terms of monads, we construct ADHM data for the Hilbert scheme of points of the total space of the line bundle $\mathcal O(-n)$ on $\mathbb P^1$. This ADHM description is then used to realize these Hilbert schemes as quiver varieties. %I arXiv:1504.02987 [math.AG] %G en %U http://urania.sissa.it/xmlui/handle/1963/34487 %1 34673 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by Ugo Bruzzo (bruzzo@sissa.it) on 2015-08-07T20:51:23Z No. of bitstreams: 1 BBLR-10.pdf: 381014 bytes, checksum: 8e0965815a5d89b7855afc29dcf7fe74 (MD5) %0 Report %D 2015 %T Homogenization problems in the Calculus of Variations: an overview %A Jose Matias %A Marco Morandotti %X In this note we present a brief overview of variational methods to solve homogenization problems. The purpose is to give a first insight on the subject by presenting some fundamental theoretical tools, both classical and modern. We conclude by mentioning some open problems. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/34455 %1 34598 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-03-18T12:11:41Z No. of bitstreams: 1 surveyhom1.pdf: 297678 bytes, checksum: be0ffd687370fdf3bf6a57d4f6dc61e4 (MD5) %0 Thesis %D 2015 %T Integrability of Continuous Tangent Sub-bundles %A Sina Tureli %K Dynamical Systems, Global Analysis, Frobenius Theorem, Integrability %X In this thesis, the main aim is to study the integrability properties of continuous tangent sub-bundles, especially those that arise in the study of dynamical systems. After the introduction and examples part we start by studying integrability of such sub-bundles under different regularity and dynamical assumptions. Then we formulate a continuous version of the classical Frobenius theorem and state some applications to such bundles, to ODE and PDE. Finally we close of by stating some ongoing work related to interactions between integrability, sub-Riemannian geometry and contact geometry. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/34630 %1 34833 %2 Mathematics %# MAT/05 %$ Submitted by stureli@sissa.it (stureli@sissa.it) on 2015-10-13T01:32:04Z No. of bitstreams: 1 thesis-sina-tureli-2015.pdf: 526450 bytes, checksum: 9ff71f05dd4ee459ef37ff150ebb272e (MD5) %0 Thesis %D 2015 %T Interaction functionals, Glimm approximations and Lagrangian structure of BV solutions for Hyperbolic Systems of Conservations Laws %A Stefano Modena %K Hyperbolic conservation laws %X This thesis is a contribution to the mathematical theory of Hyperbolic Conservation Laws. Three are the main results which we collect in this work. The first and the second result (denoted in the thesis by Theorem A and Theorem B respectively) deal with the following problem. The most comprehensive result about existence, uniqueness and stability of the solution to the Cauchy problem \begin{equation}\tag{$\mathcal C$} \label{E:abstract} \begin{cases} u_t + F(u)_x = 0, \\u(0, x) = \bar u(x), \end{cases} \end{equation} where $F: \R^N \to \R^N$ is strictly hyperbolic, $u = u(t,x) \in \R^N$, $t \geq 0$, $x \in \R$, $\TV(\bar u) \ll 1$, can be found in [Bianchini, Bressan 2005], where the well-posedness of \eqref{E:abstract} is proved by means of vanishing viscosity approximations. After the paper [Bianchini, Bressan 2005], however, it seemed worthwhile to develop a \emph{purely hyperbolic} theory (based, as in the genuinely nonlinear case, on Glimm or wavefront tracking approximations, and not on vanishing viscosity parabolic approximations) to prove existence, uniqueness and stability results. The reason of this interest can be mainly found in the fact that hyperbolic approximate solutions are much easier to study and to visualize than parabolic ones. Theorems A and B in this thesis are a contribution to this line of research. In particular, Theorem A proves an estimate on the change of the speed of the wavefronts present in a Glimm approximate solution when two of them interact; Theorem B proves the convergence of the Glimm approximate solutions to the weak admissible solution of \eqref{E:abstract} and provides also an estimate on the rate of convergence. Both theorems are proved in the most general setting when no assumption on $F$ is made except the strict hyperbolicity. The third result of the thesis, denoted by Theorem C, deals with the Lagrangian structure of the solution to \eqref{E:abstract}. The notion of Lagrangian flow is a well-established concept in the theory of the transport equation and in the study of some particular system of conservation laws, like the Euler equation. However, as far as we know, the general system of conservations laws \eqref{E:abstract} has never been studied from a Lagrangian point of view. This is exactly the subject of Theorem C, where a Lagrangian representation for the solution to the system \eqref{E:abstract} is explicitly constructed. The main reasons which led us to look for a Lagrangian representation of the solution of \eqref{E:abstract} are two: on one side, this Lagrangian representation provides the continuous counterpart in the exact solution of \eqref{E:abstract} to the well established theory of wavefront approximations; on the other side, it can lead to a deeper understanding of the behavior of the solutions in the general setting, when the characteristic field are not genuinely nonlinear or linearly degenerate. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/34542 %1 34739 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by smodena@sissa.it (smodena@sissa.it) on 2015-09-22T13:24:32Z No. of bitstreams: 1 Modena_tesi_2015_09_22.pdf: 1531188 bytes, checksum: 814a6709a4fcbf8b10bc95a9e3d155c7 (MD5) %0 Report %D 2015 %T Krein-Vishik-Birman self-adjoint extension theory revisited %A Alessandro Michelangeli %X The core results of the so-called Krein-Vishik-Birman theory of self-adjoint extensions of semi-bounded symmetric operators are reproduced, both in their original and in a more modern formulation, within a comprehensive discussion that includes missing details, elucidative steps, and intermediate results of independent interest. %G en %U http://urania.sissa.it/xmlui/handle/1963/35174 %1 35456 %2 Mathematics %4 1 %# MAT/07 %$ Submitted by Alessandro Michelangeli (alemiche@sissa.it) on 2016-02-20T17:27:57Z No. of bitstreams: 1 SISSA_preprint_59-2015-MATE.pdf: 578084 bytes, checksum: bfefe9b73e440c280422cf83fe48688e (MD5) %0 Journal Article %D 2015 %T Liquid crystal elastomer strips as soft crawlers %A Antonio DeSimone %A Paolo Gidoni %A Giovanni Noselli %X In this paper, we speculate on a possible application of Liquid Crystal Elastomers to the field of soft robotics. In particular, we study a concept for limbless locomotion that is amenable to miniaturisation. For this purpose, we formulate and solve the evolution equations for a strip of nematic elastomer, subject to directional frictional interactions with a flat solid substrate, and cyclically actuated by a spatially uniform, time-periodic stimulus (e.g., temperature change). The presence of frictional forces that are sensitive to the direction of sliding transforms reciprocal, 'breathing-like' deformations into directed forward motion. We derive formulas quantifying this motion in the case of distributed friction, by solving a differential inclusion for the displacement field. The simpler case of concentrated frictional interactions at the two ends of the strip is also solved, in order to provide a benchmark to compare the continuously distributed case with a finite-dimensional benchmark. We also provide explicit formulas for the axial force along the crawler body. %I Elsevier %G en %U http://urania.sissa.it/xmlui/handle/1963/34643 %1 34847 %$ Approved for entry into archive by Maria Pia Calandra (calapia@sissa.it) on 2015-10-21T08:41:13Z (GMT) No. of bitstreams: 0 %R 10.1016/j.jmps.2015.07.017 %0 Report %D 2015 %T Lower semicontinuity of a class of integral functionals on the space of functions of bounded deformation %A Gianni Dal Maso %A Gianluca Orlando %A Rodica Toader %X We study the lower semicontinuity of some free discontinuity functionals, whose volume term depends on the Euclidean norm of the symmetrized gradient. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/34533 %1 34742 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by Gianluca Orlando (gorlando@sissa.it) on 2015-09-24T10:00:30Z No. of bitstreams: 1 DM-Orl-Toa-sissa.pdf: 511329 bytes, checksum: e1c0d636e2255f0bea8777935b2a4a36 (MD5) %0 Report %D 2015 %T A lower semicontinuity result for a free discontinuity functional with a boundary term %A Stefano Almi %A Gianni Dal Maso %A Rodica Toader %X We study the lower semicontinuity in $GSBV^{p}(\Om;\R^{m})$ of a free discontinuity functional~$\F(u)$ that can be written as the sum of a crack term, depending only on the jump set~$S_{u}$, and of a boundary term, depending on the trace of~$u$ on~$\partial\Om$. We give sufficient conditions on the integrands for the lower semicontinuity of~$\F$. Moreover, we prove a relaxation result, which shows that, if these conditions are not satisfied, the lower semicontinuous envelope of~$\F$ can be represented by the sum of two integrals on~$S_{u}$ and~$\partial\Om$, respectively. %G en %U http://urania.sissa.it/xmlui/handle/1963/35146 %1 34731 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by salmi@sissa.it (salmi@sissa.it) on 2015-12-15T14:37:19Z No. of bitstreams: 1 Alm-DM-Toa-15-sissa.pdf: 351559 bytes, checksum: b6adddc4944478676c7d4b34028a347c (MD5) %0 Thesis %D 2015 %T Mathematical Models of Locomotion: Legged Crawling, Snake-like Motility, and Flagellar Swimming %A Giancarlo Cicconofri %K Motility %I SISSA %G en %1 34743 %2 Mathematics %4 1 %# FIS/02 %$ Submitted by cicconof@sissa.it (cicconof@sissa.it) on 2015-09-24T20:39:35Z No. of bitstreams: 1 TESI_Cicconofri.pdf: 4716549 bytes, checksum: 708afb866eb4c106392495f2a8e7c6a8 (MD5) %0 Journal Article %J Advances in Computational Mathematics %D 2015 %T Model order reduction of parameterized systems (MoRePaS): Preface to the special issue of advances in computational mathematics %A Benner, P. %A Ohlberger, M. %A Patera, A.T. %A Rozza, G. %A Sorensen, D.C. %A Urban, K. %B Advances in Computational Mathematics %V 41 %P 955–960 %G eng %R 10.1007/s10444-015-9443-y %0 Thesis %D 2015 %T Multidimensional Poisson Vertex Algebras and Poisson cohomology of Hamiltonian operators of hydrodynamic type %A Matteo Casati %K Poisson Vertex Algebras, Poisson brackets, Hamiltonian operators, Integrable Systems %X The Poisson brackets of hydrodynamic type, also called Dubrovin-Novikov brackets, constitute the Hamiltonian structure of a broad class of evolutionary PDEs, that are ubiquitous in the theory of Integrable Systems, ranging from Hopf equation to the principal hierarchy of a Frobenius manifold. They can be regarded as an analogue of the classical Poisson brackets, defined on an infinite dimensional space of maps Σ → M between two manifolds. Our main problem is the study of Poisson-Lichnerowicz cohomology of such space when dim Σ > 1. We introduce the notion of multidimensional Poisson Vertex Algebras, generalizing and adapting the theory by A. Barakat, A. De Sole, and V. Kac [Poisson Vertex Algebras in the theory of Hamiltonian equations, 2009]; within this framework we explicitly compute the first nontrivial cohomology groups for an arbitrary Poisson bracket of hydrodynamic type, in the case dim Σ = dim M = 2. For the case of the so-called scalar brackets, namely the ones for which dim M = 1, we give a complete description on their Poisson–Lichnerowicz cohomology. From this computations it follows, already in the particular case dim Σ = 2, that the cohomology is infinite dimensional. %I SISSA %G en %1 34902 %2 Mathematics %4 1 %# MAT/07 %$ Submitted by Matteo Casati (mcasati@sissa.it) on 2015-10-22T07:27:52Z No. of bitstreams: 1 PhDThesis_Casati.pdf: 1027291 bytes, checksum: 49f551db40603ca035f2515ccb6ec7a2 (MD5) %0 Journal Article %J Numerische Mathematik, (2015), 36 p. Article in Press %D 2015 %T Multilevel and weighted reduced basis method for stochastic optimal control problems constrained by Stokes equations %A Gianluigi Rozza %A Peng Chen %A Alfio Quarteroni %X In this paper we develop and analyze a multilevel weighted reduced basis method for solving stochastic optimal control problems constrained by Stokes equations. We prove the analytic regularity of the optimal solution in the probability space under certain assumptions on the random input data. The finite element method and the stochastic collocation method are employed for the numerical approximation of the problem in the deterministic space and the probability space, respectively, resulting in many large-scale optimality systems to solve. In order to reduce the unaffordable computational effort, we propose a reduced basis method using a multilevel greedy algorithm in combination with isotropic and anisotropic sparse-grid techniques. A weighted a posteriori error bound highlights the contribution stemming from each method. Numerical tests on stochastic dimensions ranging from 10 to 100 demonstrate that our method is very efficient, especially for solving high-dimensional and large-scale optimization problems. %B Numerische Mathematik, (2015), 36 p. Article in Press %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34491 %1 34680 %2 Mathematics %4 1 %# MAT/08 %$ Submitted by Gianluigi Rozza (grozza@sissa.it) on 2015-08-25T23:32:48Z No. of bitstreams: 1 06August2014_wRBM4SOC.pdf: 531409 bytes, checksum: d1a2f18b0de17872919c430779f7180c (MD5) %R 10.1007/s00211-015-0743-4 %0 Journal Article %J J. Differential Equations 259 (2015), 925–963. %D 2015 %T Multiple positive solutions for a superlinear problem: a topological approach %A Guglielmo Feltrin %A Fabio Zanolin %X We study the multiplicity of positive solutions for a two-point boundary value problem associated to the nonlinear second order equation u''+f(x,u)=0. We allow x ↦ f(x,s) to change its sign in order to cover the case of scalar equations with indefinite weight. Roughly speaking, our main assumptions require that f(x,s)/s is below λ_1 as s→0^+ and above λ_1 as s→+∞. In particular, we can deal with the situation in which f(x,s) has a superlinear growth at zero and at infinity. We propose a new approach based on the topological degree which provides the multiplicity of solutions. Applications are given for u'' + a(x) g(u) = 0, where we prove the existence of 2^n-1 positive solutions when a(x) has n positive humps and a^-(x) is sufficiently large. %B J. Differential Equations 259 (2015), 925–963. %I Elsevier %G en %U http://urania.sissa.it/xmlui/handle/1963/35147 %1 35387 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-12-17T09:31:06Z No. of bitstreams: 1 FeltrinZanolin_jde2015.pdf: 350880 bytes, checksum: 0e329b01081df570863ea2492ffefe0a (MD5) %R 10.1016/j.jde.2015.02.032 %0 Thesis %D 2015 %T Normal matrix models and orthogonal polynomials for a class of potentials with discrete rotational symmetries %A Dario Merzi %K Mathematical Physics %X In this thesis we are going to study normal random matrix models which generalize naturally the polynomially perturbed Ginibre ensamble, focusing in particular on their eigenvalue distribution and on the asymptotics of the associated orthogonal polynomials. \\ The main result we are going to present are the following: \begin{itemize} \item we describe the explicit derivation of the equilibrium measure for a class of potentials with discrete rotational symmetries, namely of the form \[V(z)=|z|^{2n}-t(z^{d}+\bar{z}^{d})\qquad n,d\in\mathbb{N},\ \ d\leq2n\ \ t>0 .\] \item We obtain the strong asymptotics for the orthogonal polynomials associated to the weight \[ e^{-NV(z)},\quad V(z)=|z|^{2s}-t(z^s+\bar{z}^{s}) \qquad z \in \mathbb{C},\;s\in \mathbb{N},\quad t>0,\] and we will show how the density of their zeroes is related to the eigenvalue distribution of the corresponding matrix model; \item We show how the conformal maps used to describe the support of the equilibrium measure for polynomial perturbation of the potential $V(z)=|z|^{2n}$ lead to a natural generalization of the concept of polynomial curves introduced in by Elbau. \end{itemize} %I SISSA %G en %1 34938 %2 Mathematics %4 1 %# MAT/07 %$ Submitted by Dario Merzi (dmerzi@sissa.it) on 2015-10-24T00:25:34Z No. of bitstreams: 1 Tesi.pdf: 2303697 bytes, checksum: 620bce2fe472d72e2a7050687b21dc08 (MD5) %0 Journal Article %J Battaglia Luca, Mancini Gabriele: A note on compactness properties of the singular Toda system. Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. vol. 26, (2015), pages : 299-307. doi: 10.4171/RLM/708 %D 2015 %T A note on compactness properties of the singular Toda system %A Luca Battaglia %A Gabriele Mancini %X In this note, we consider blow-up for solutions of the SU(3) Toda system on compact surfaces. In particular, we give a complete proof of a compactness result stated by Jost, Lin and Wang and we extend it to the case of singular systems. This is a necessary tool to find solutions through variational methods. %B Battaglia Luca, Mancini Gabriele: A note on compactness properties of the singular Toda system. Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. vol. 26, (2015), pages : 299-307. doi: 10.4171/RLM/708 %G en %U http://urania.sissa.it/xmlui/handle/1963/34484 %1 34669 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by gmancini@sissa.it (gmancini@sissa.it) on 2015-08-07T16:01:01Z No. of bitstreams: 1 art3.pdf: 146803 bytes, checksum: 362923e2dd63f86658dd3bb0701ce05b (MD5) %R 10.4171/RLM/708 %0 Report %D 2015 %T A note on the convergence of a singularly perturbed second order potential-type equation %A Lorenzo Nardini %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/34453 %1 34595 %2 Mathematics %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-03-11T15:56:50Z No. of bitstreams: 1 sissa_12_mate.pdf: 200944 bytes, checksum: 4e12163c18c9921ef711b6b4071f3f41 (MD5) %0 Journal Article %D 2015 %T Onofri-Type Inequalities for Singular Liouville Equations %A Gabriele Mancini %X We study the blow-up behavior of minimizing sequences for the singular Moser–Trudinger functional on compact surfaces. Assuming non-existence of minimum points, we give an estimate for the infimum value of the functional. This result can be applied to give sharp Onofri-type inequalities on the sphere in the presence of at most two singularities. %I Springer US %G en %1 34668 %2 Mathematics %4 1 %# MAT/05 %R 10.1007/s12220-015-9589-3 %0 Journal Article %D 2015 %T The phototransduction machinery in the rod outer segment has a strong efficacy gradient %A Monica Mazzolini %A Giuseppe Facchetti %A L. Andolfi %A R. Proietti Zaccaria %A S. Tuccio %A J. Treud %A Claudio Altafini %A Enzo M. Di Fabrizio %A Marco Lazzarino %A G. Rapp %A Vincent Torre %I National Academy of Sciences %G en %U http://urania.sissa.it/xmlui/handle/1963/35157 %1 35382 %2 Neuroscience %$ Approved for entry into archive by Lucio Lubiana (lubiana@sissa.it) on 2016-01-21T09:29:28Z (GMT) No. of bitstreams: 0 %R 10.1073/pnas.1423162112 %0 Report %D 2015 %T Poisson cohomology of scalar multidimensional Dubrovin-Novikov brackets %A Guido Carlet %A Matteo Casati %A Sergey Shadrin %X We compute the Poisson cohomology of a scalar Poisson bracket of Dubrovin-Novikov type with D independent variables. We find that the second and third cohomology groups are generically non-vanishing in D>1. Hence, in contrast with the D=1 case, the deformation theory in the multivariable case is non-trivial. %G en %1 35389 %2 Mathematics %4 1 %# MAT/03 %0 Thesis %D 2015 %T Principal circle bundles, Pimsner algebras and Gysin sequences %A Francesca Arici %X Principal circle bundles and Gysin sequences play a crucial role in mathematical physics, in particular in Chern-Simons theories and T-duality. This works focuses on the noncommutative topology of principal circle bundles: we investigate the connections between noncommutative principal circle bundles, Pimsner algebras and strongly graded algebras. At the C*-algebraic level, we start from a self-Morita equivalence bimodule E for a C*-algebra B which we think of as a non commutative line bundle over the `base space’ algebra B. The corresponding Pimsner algebra O_E, is then the total space algebra of an associated circle bundle. A natural six term exact sequence, an analogue of the Gysin sequence for circle bundles, relates the KK-theories of O_E and of the base space B. We illustrate several results with the examples of quantum weighted projective and lens spaces. %I SISSA %G en %1 34744 %2 Mathematics %4 1 %# MAT/07 %$ Submitted by Francesca Arici (farici@sissa.it) on 2015-09-26T07:48:48Z No. of bitstreams: 1 AriciThesis.pdf: 983966 bytes, checksum: 4eadf33259d623493f52eaba5c45ec90 (MD5) %0 Report %D 2015 %T Quadratic interaction estimate for conservation laws: motivations, techniques and open problems %A Stefano Modena %X In a series joint works with S. Bianchini [3, 4, 5], we proved a quadratic interaction estimate for general systems of conservation laws. Aim of this article is to present the results obtained in the three cited papers, setting them in the context of the theory of Hyperbolic Conservation Laws. To this purpose, first we explain why we considered this quadratic estimate interesting, then we give a brief overview of the techniques we used to prove it and finally we present some related open problems. %G en %1 34623 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-03-31T08:32:42Z No. of bitstreams: 1 Modena_Proceedings.pdf: 322083 bytes, checksum: 2e238451184b9a552cbcd22e23063ab6 (MD5) %0 Journal Article %J Advances in Computational Mathematics %D 2015 %T Reduced basis approximation and a-posteriori error estimation for the coupled Stokes-Darcy system %A Immanuel Martini %A Gianluigi Rozza %A Bernard Haasdonk %K Domain decomposition %K Error estimation %K Non-coercive problem %K Porous medium equation %K Reduced basis method %K Stokes flow %XThe coupling of a free flow with a flow through porous media has many potential applications in several fields related with computational science and engineering, such as blood flows, environmental problems or food technologies. We present a reduced basis method for such coupled problems. The reduced basis method is a model order reduction method applied in the context of parametrized systems. Our approach is based on a heterogeneous domain decomposition formulation, namely the Stokes-Darcy problem. Thanks to an offline/online-decomposition, computational times can be drastically reduced. At the same time the induced error can be bounded by fast evaluable a-posteriori error bounds. In the offline-phase the proposed algorithms make use of the decomposed problem structure. Rigorous a-posteriori error bounds are developed, indicating the accuracy of certain lifting operators used in the offline-phase as well as the accuracy of the reduced coupled system. Also, a strategy separately bounding pressure and velocity errors is extended. Numerical experiments dealing with groundwater flow scenarios demonstrate the efficiency of the approach as well as the limitations regarding a-posteriori error estimation.

%B Advances in Computational Mathematics %V special issue for MoRePaS 2012 %G eng %N in press %R 10.1007/s10444-014-9396-6 %0 Journal Article %J Lecture Notes in Computational Science and Engineering %D 2015 %T Reduced basis approximation of parametrized advection-diffusion PDEs with high Péclet number %A Pacciarini, P. %A Rozza, G. %X In this work we show some results about the reduced basis approximation of advection dominated parametrized problems, i.e. advection-diffusion problems with high Péclet number. These problems are of great importance in several engineering applications and it is well known that their numerical approximation can be affected by instability phenomena. In this work we compare two possible stabilization strategies in the framework of the reduced basis method, by showing numerical results obtained for a steady advection-diffusion problem. %B Lecture Notes in Computational Science and Engineering %V 103 %P 419–426 %G eng %R 10.1007/978-3-319-10705-9__41 %0 Journal Article %J Computers and Mathematics with Applications %D 2015 %T Reduced basis approximation of parametrized optimal flow control problems for the Stokes equations %A Negri, F. %A Manzoni, A. %A Rozza, G. %X This paper extends the reduced basis method for the solution of parametrized optimal control problems presented in Negri et al. (2013) to the case of noncoercive (elliptic) equations, such as the Stokes equations. We discuss both the theoretical properties-with particular emphasis on the stability of the resulting double nested saddle-point problems and on aggregated error estimates-and the computational aspects of the method. Then, we apply it to solve a benchmark vorticity minimization problem for a parametrized bluff body immersed in a two or a three-dimensional flow through boundary control, demonstrating the effectivity of the methodology. %B Computers and Mathematics with Applications %V 69 %P 319–336 %G eng %R 10.1016/j.camwa.2014.12.010 %0 Journal Article %J Comput Methods Appl Mech Eng. 2015;284:1147–1180 %D 2015 %T Reduced Basis Isogeometric Methods (RB-IGA) for the real-time simulation of potential flows about parametrized NACA airfoils %A Andrea Manzoni %A Filippo Salmoiraghi %A Luca Heltai %X We present a Reduced Basis (RB) method based on Isogeometric Analysis (IGA) for the rapid and reliable evaluation of PDE systems characterized by complex geometrical features. At the current state of the art, this is the first case of coupling between RB and IGA methods. The construction of the RB method relies on an Isogeometric Boundary Element Method (IGA-BEM) as the high-fidelity technique, allowing a direct interface with Computer Aided Design (CAD) tools. A suitable Empirical Interpolation Method (EIM) ensures an efficient offline/online decomposition between the construction and the evaluation of the RB method. We consider the real-time simulation of potential flows past airfoils, parametrized with respect to the angle of attack and the NACA number identifying their shape, and we provide a validation of our methodology with respect to experimental data and reference numerical codes, showing in both cases a very good agreement.We present a Reduced Basis (RB) method based on Isogeometric Analysis (IGA) for the rapid and reliable evaluation of PDE systems characterized by complex geometrical features. At the current state of the art, this is the first case of coupling between RB and IGA methods. The construction of the RB method relies on an Isogeometric Boundary Element Method (IGA-BEM) as the high-fidelity technique, allowing a direct interface with Computer Aided Design (CAD) tools. A suitable Empirical Interpolation Method (EIM) ensures an efficient offline/online decomposition between the construction and the evaluation of the RB method. We consider the real-time simulation of potential flows past airfoils, parametrized with respect to the angle of attack and the NACA number identifying their shape, and we provide a validation of our methodology with respect to experimental data and reference numerical codes, showing in both cases a very good agreement. %B Comput Methods Appl Mech Eng. 2015;284:1147–1180 %G en %1 34587 %2 Mathematics %4 1 %# MAT/08 %$ Submitted by Luca Heltai (heltai@sissa.it) on 2015-03-03T16:15:31Z No. of bitstreams: 1 RB_IGA_BEM.pdf: 725470 bytes, checksum: e2fe6fabfdbe6118e9ef07fb185113af (MD5) %R 10.1016/j.cma.2014.11.037 %0 Thesis %D 2015 %T The relaxed area of maps from the plane to the plane with a line discontinuity, and the role of semicartesian surfaces. %A Lucia Tealdi %K Area functional %X In this thesis we study the relaxation of the area functional w.r.t. the L^1 topology of a map from a bounded planar domain with values in the plane and jumping on a segment. We estimate from above the singular contribution of this functional due to the presence of the jump in terms of the infimum of the area among a suitable family of surfaces that we call semicartesian surfaces. In our analysis, we also introduce a different notion of area, namely the relaxation of the area w.r.t. a convergence stronger than the L^1 convergence, whose singular contribution is completely characterized in terms of suitable semicartesian area minimizing problems. We propose also some examples of maps for which the two notions of relaxation are different: these examples underline the highly non-local behaviour of the L^1-relaxation, and justify the introduction of the other functional. Some result about the existence of a semicartesian area-minimizing surface is also provided. %I SISSA %G en %1 34732 %4 1 %# MAT/05 %$ Submitted by Lucia Tealdi (ltealdi@sissa.it) on 2015-09-21T12:23:44Z No. of bitstreams: 1 Tealdi_PhD_thesis.pdf: 917244 bytes, checksum: a6bfc90b8457a030be4c7314ee1f426f (MD5) %0 Report %D 2015 %T Results on the minimization of the Dirichlet functional among semicartesian parametrizations %A Lucia Tealdi %A Giovanni Bellettini %A Maurizio Paolini %X We start to investigate the existence of conformal minimizers for the Dirichlet functional in the setting of the so-called semicartesian parametrizations, adapting to this context some techniques used in solving the classical Plateau's problem. The final goal is to find area minimizing semicartesian parametrizations spanning a Jordan curve obtained as union of two graphs; this problem appeared in the study of the relaxed area functional for maps from the plane to the plane jumping on a line. %G en %U http://urania.sissa.it/xmlui/handle/1963/34488 %1 34671 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by Lucia Tealdi (ltealdi@sissa.it) on 2015-08-07T16:12:37Z No. of bitstreams: 1 bellettini_paolini_tealdi_semicart.pdf: 338138 bytes, checksum: c689a5b64d30dc600fe0429b72996c7d (MD5) %0 Report %D 2015 %T Rigidity of three-dimensional lattices and dimension reduction in heterogeneous nanowires %A Giuliano Lazzaroni %A Mariapia Palombaro %A Anja Schlomerkemper %X In the context of nanowire heterostructures we perform a discrete to continuum limit of the corresponding free energy by means of Γ-convergence techniques. Nearest neighbours are identified by employing the notions of Voronoi diagrams and Delaunay triangulations. The scaling of the nanowire is done in such a way that we perform not only a continuum limit but a dimension reduction simultaneously. The main part of the proof is a discrete geometric rigidity result that we announced in an earlier work and show here in detail for a variety of three-dimensional lattices. We perform the passage from discrete to continuum twice: once for a system that compensates a lattice mismatch between two parts of the heterogeneous nanowire without defects and once for a system that creates dislocations. It turns out that we can verify the experimentally observed fact that the nanowires show dislocations when the radius of the specimen is large %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/7494 %1 7623 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-01-30T07:54:33Z No. of bitstreams: 1 LaPaSc-3dim.pdf: 249836 bytes, checksum: 8b8edddc952b9a4a084c1c0c85514051 (MD5) %0 Report %D 2015 %T Schödinger operators on half-line with shrinking potentials at the origin %A Gianfausto Dell'Antonio %A Alessandro Michelangeli %X We discuss the general model of a Schrödinger quantum particle constrained on a straight half-line with given self-adjoint boundary condition at the origin and an interaction potential supported around the origin. We study the limit when the range of the potential scales to zero and its magnitude blows up. We show that in the limit the dynamics is generated by a self-adjoint negative Laplacian on the half-line, with a possible preservation or modification of the boundary condition at the origin, depending on the magnitude of the scaling and of the strength of the potential. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/34439 %1 34566 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-02-09T07:28:40Z No. of bitstreams: 1 SISSA_preprint_06-2015-MATE.pdf: 177243 bytes, checksum: 383296953d36b4cec0cb4cfb55e95d7f (MD5) %0 Report %D 2015 %T Semicartesian surfaces and the relaxed area of maps from the plane to the plane with a line discontinuity %A Lucia Tealdi %A Giovanni Bellettini %A Maurizio Paolini %X We address the problem of estimating the area of the graph of a map u, defined on a bounded planar domain O and taking values in the plane, jumping on a segment J, either compactly contained in O or having both the end points on the boundary of O. We define the relaxation of the area functional w.r.t. a sort of uniform convergence, and we characterize it in terms of the infimum of the area among those surfaces in the space spanning the graphs of the traces of u on the two side of J and having what we have called a semicartesian structure. We exhibit examples showing that the relaxed area functional w.r.t the L^1 convergence may depend also on the values of u far from J, and on the relative position of J w.r.t. the boundary of O; these examples confirm the non-local behaviour of the L^1 relaxed area functional, and justify the interest in studying the relaxation w.r.t. a stronger convergence. We prove also that the L^1 relaxed area functional in non-subadditive for a rather class of maps. %G en %U http://urania.sissa.it/xmlui/handle/1963/34483 %1 34670 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by Lucia Tealdi (ltealdi@sissa.it) on 2015-08-07T16:06:48Z No. of bitstreams: 1 bellettini_paolini_tealdi_semicartesian.pdf: 623410 bytes, checksum: 871f66c4686a39ad7d1bc996f0e2b0aa (MD5) %0 Thesis %D 2015 %T Sharp Inequalities and Blow-up Analysis for Singular Moser-Trudinger Embeddings. %A Gabriele Mancini %K Moser-Trudinger %X We investigate existence of solutions for a singular Liouville equation on S^2 and prove sharp Onofri-type inequalities for a Moser-Trudinger functional in the presence of singular potentials. As a consequence we obtain existence of extremal functions for the Moser-Trudinger embedding on compact surfaces with conical singularities. Finally we study the blow-up behavior for sequences of solutions Liouville-type systems and prove a compactness condition which plays an important role in the variational analysis of Toda systems. %I SISSA %G en %1 34738 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by gmancini@sissa.it (gmancini@sissa.it) on 2015-09-22T12:27:17Z No. of bitstreams: 1 tesi4.pdf: 1376221 bytes, checksum: cfc85996d91a3384e94546a64bf8c479 (MD5) %0 Report %D 2015 %T Singular Liouville Equations on S^2: Sharp Inequalities and Existence Results %A Gabriele Mancini %X We prove a sharp Onofri-type inequality and non-existence of extremals for a Moser-Tudinger functional on S^2 in the presence of potentials having positive order singularities. We also investigate the existence of critical points and give some sufficient conditions under symmetry or nondegeneracy assumptions. %G en %U http://urania.sissa.it/xmlui/handle/1963/34489 %1 34672 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by gmancini@sissa.it (gmancini@sissa.it) on 2015-08-11T09:06:30Z No. of bitstreams: 1 art4.pdf: 352978 bytes, checksum: 4e081003a6b037544c46954c3d44b826 (MD5) %0 Thesis %D 2015 %T Some results on anisotropic mean curvature and other phase-transition problems %A Stefano Amato %K Anisotropic mean curvature %X The present thesis is divided into three parts. In the first part, we analyze a suitable regularization — which we call nonlinear multidomain model — of the motion of a hypersurface under smooth anisotropic mean curvature flow. The second part of the thesis deals with crystalline mean curvature of facets of a solid set of R^3 . Finally, in the third part we study a phase-transition model for Plateau’s type problems based on the theory of coverings and of BV functions. %I SISSA %G en %1 34733 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by Stefano Amato (samato@sissa.it) on 2015-09-21T12:36:18Z No. of bitstreams: 1 tesi.pdf: 1566254 bytes, checksum: be7cf105a787693fd374acc1afe44fc3 (MD5) %0 Report %D 2015 %T Stability of closed gaps for the alternating Kronig-Penney Hamiltonian %A Alessandro Michelangeli %A Domenico Monaco %X We consider the Kronig-Penney model for a quantum crystal with equispaced periodic delta-interactions of alternating strength. For this model all spectral gaps at the centre of the Brillouin zone are known to vanish, although so far this noticeable property has only been proved through a very delicate analysis of the discriminant of the corresponding ODE and the associated monodromy matrix. We provide a new, alternative proof by showing that this model can be approximated, in the norm resolvent sense, by a model of regular periodic interactions with finite range for which all gaps at the centre of the Brillouin zone are still vanishing. In particular this shows that the vanishing gap property is stable in the sense that it is present also for the "physical" approximants and is not only a feature of the idealised model of zero-range interactions. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/34460 %1 34629 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-04-01T14:57:03Z No. of bitstreams: 1 SISSA_preprint_16-2015-MATE.pdf: 349807 bytes, checksum: f5e6dacd85fb41c96420795cc37cc12c (MD5) %0 Report %D 2015 %T Stability of the (2+2)-fermionic system with zero-range interaction %A Alessandro Michelangeli %A Paul Pfeiffer %X We introduce a 3D model, and we study its stability, consisting of two distinct pairs of identical fermions coupled with a two-body interaction between fermions of different species, whose effective range is essentially zero (a so called (2+2)-fermionic system with zero-range interaction). The interaction is modelled by implementing the the celebrated (and ubiquitous, in the literature of this field) Bethe-Peierls contact condition with given two-body scattering length within the Krein-Visik-Birman theory of extensions of semi-bounded symmetric operators, in order to make the Hamiltonian a well-defined (self-adjoint) physical observable. After deriving the expression for the associated energy quadratic form, we show analytically and numerically that the energy of the model is bounded below, thus describing a stable system. %G en %U http://urania.sissa.it/xmlui/handle/1963/34474 %1 34649 %2 Mathematics %4 1 %# MAT/07 %$ Submitted by Alessandro Michelangeli (alemiche@sissa.it) on 2015-06-24T10:47:38Z No. of bitstreams: 1 sissa-preprint-29-2015-mate.pdf: 827153 bytes, checksum: e5268c2d26f348929a3c532f9ffd3097 (MD5) %0 Journal Article %D 2015 %T Supremizer stabilization of POD-Galerkin approximation of parametrized Navier-Stokes equations %A Francesco Ballarin %A Andrea Manzoni %A Alfio Quarteroni %A Gianluigi Rozza %X In this work, we present a stable proper orthogonal decomposition–Galerkin approximation for parametrized steady incompressible Navier–Stokes equations with low Reynolds number. %I Wiley %G en %U http://urania.sissa.it/xmlui/handle/1963/34701 %1 34915 %2 Mathematics %4 1 %# MAT/08 %$ Submitted by Gianluigi Rozza (grozza@sissa.it) on 2015-10-22T11:39:58Z No. of bitstreams: 1 IJNME_2014.pdf: 6761966 bytes, checksum: ad65f2c4d2dbd30a4a1590ff42ee49a0 (MD5) %R 10.1002/nme.4772 %0 Journal Article %J Acta Applicandae Mathematicae, vol. 137, Issue 1, 2015, pages: 185-203 %D 2015 %T Symmetry and localization in periodic crystals: triviality of Bloch bundles with a fermionic time-reversal symmetry %A Domenico Monaco %A Gianluca Panati %X We describe some applications of group- and bundle-theoretic methods in solid state physics, showing how symmetries lead to a proof of the localization of electrons in gapped crystalline solids, as e.g. insulators and semiconductors. We shortly review the Bloch-Floquet decomposition of periodic operators, and the related concepts of Bloch frames and composite Wannier functions. We show that the latter are almost-exponentially localized if and only if there exists a smooth periodic Bloch frame, and that the obstruction to the latter condition is the triviality of a Hermitian vector bundle, called the Bloch bundle. The rôle of additional Z_2-symmetries, as time-reversal and space-reflection symmetry, is discussed, showing how time-reversal symmetry implies the triviality of the Bloch bundle, both in the bosonic and in the fermionic case. Moreover, the same Z_2-symmetry allows to define a finer notion of isomorphism and, consequently, to define new topological invariants, which agree with the indices introduced by Fu, Kane and Mele in the context of topological insulators. %B Acta Applicandae Mathematicae, vol. 137, Issue 1, 2015, pages: 185-203 %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34468 %1 34642 %2 Mathematics %4 1 %# MAT/07 %$ Submitted by Domenico Monaco (dmonaco@sissa.it) on 2015-05-15T10:12:11Z No. of bitstreams: 1 CalaGonone.pdf: 500680 bytes, checksum: 00aa2839c4d737f45da3d828e5cc0a53 (MD5) %R 10.1007/s10440-014-9995-8 %0 Journal Article %D 2015 %T Three-sphere low-Reynolds-number swimmer with a passive elastic arm %A A. Montino %A Antonio DeSimone %X One of the simplest model swimmers at low Reynolds number is the three-sphere swimmer by Najafi and Golestanian. It consists of three spheres connected by two rods which change their lengths periodically in non-reciprocal fashion. Here we investigate a variant of this model in which one rod is periodically actuated while the other is replaced by an elastic spring. We show that the competition between the elastic restoring force and the hydrodynamic drag produces a delay in the response of the passive elastic arm with respect to the active one. This leads to non-reciprocal shape changes and self-propulsion. After formulating the equations of motion, we study their solutions qualitatively and numerically. The leading-order term of the solution is computed analytically. We then address questions of optimization with respect to both actuation frequency and swimmer's geometry. Our results can provide valuable conceptual guidance in the engineering of robotic microswimmers. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34530 %1 34735 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-09-22T07:16:17Z No. of bitstreams: 1 art_10.1140_epje_i2015-15042-3.pdf: 766953 bytes, checksum: 7c5396c7e15baff264376c63eaf2248b (MD5) %R 10.1140/epje/i2015-15042-3 %0 Report %D 2015 %T Translation and adaptation of Birman's paper "On the theory of self-adjoint extensions of positive definite operators" (1956) %A Mikhail Khotyakov %A Alessandro Michelangeli %X This is an accurate translation from Russian and adaptation to the modern mathematical jargon of a classical paper by M. Sh. Birman published in 1956, which is still today central in the theory of self-adjoint extensions of semi-bounded operators, and for which yet no English version was available so far. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/34443 %1 34570 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-02-13T10:07:37Z No. of bitstreams: 1 SISSA_preprint_08-2015-MATE(1).pdf: 2044497 bytes, checksum: 092e3561b5722c604c896ccc97db7a76 (MD5) %0 Thesis %D 2015 %T Variational aspects of Liouville equations and systems %A Aleks Jevnikar %K Toda system %I SISSA %G en %1 34676 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by ajevnika@sissa.it (ajevnika@sissa.it) on 2015-08-08T16:04:38Z No. of bitstreams: 1 tesi phd.pdf: 1034249 bytes, checksum: 6988a3a6220b4d1bbd38c3124f520655 (MD5) %0 Thesis %D 2015 %T Variational aspects of singular Liouville systems %A Luca Battaglia %K Variational methods, Liouville systems, Moser-Trudinger inequalities, min-max methods %X I studied singular Liouville systems on compact surfaces from a variational point of view. I gave sufficient and necessary conditions for the existence of globally minimizing solutions, then I found min-max solutions for some particular systems. Finally, I also gave some non-existence results. %I SISSA %G en %1 34737 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by lbatta@sissa.it (lbatta@sissa.it) on 2015-09-22T09:49:56Z No. of bitstreams: 1 thesis0.pdf: 1795685 bytes, checksum: e981358904223d6649e47eb70e6da429 (MD5) %0 Report %D 2015 %T Viscous approximation of quasistatic evolutions for a coupled elastoplastic-damage model %A Vito Crismale %A Giuliano Lazzaroni %X Employing the technique of vanishing viscosity and time rescaling, we show the exis- tence of quasistatic evolutions for elastoplastic materials with incomplete damage affecting both the elastic tensor and the plastic yield surface, in a softening framework and in small strain assumptions. %I SISSA %G en_US %1 7624 %$ Submitted by vcrisma@sissa.it (vcrisma@sissa.it) on 2015-01-30T17:58:56Z No. of bitstreams: 1 QSEvoPlasVan.pdf: 513862 bytes, checksum: ee1171b4f0fd87d68e69d858a91c5832 (MD5) %0 Thesis %D 2015 %T Volume variation and heat kernel for affine control problems %A Elisa Paoli %K Heat kernel asymptotics %X In this thesis we study two main problems. The first one is the small-time heat kernel expansion on the diagonal for second order hypoelliptic opeartors. We consider operators that can depend on a drift field and that satisfy only the weak Hörmander condition. In a first work we use perturbation techniques to determine the exact order of decay of the heat kernel, that depends on the Lie algebra generated by the fields involved in the hypoelliptic operator. We generalize in particular some results already obtained in the sub-Riemannian setting. In a second work we consider a model class of hypoelliptic operators and we characterize geometrically all the coefficients in the on-the diagonal asymptotics at the equilibrium points of the drift field. The class of operators that we consider contains the linear hypoelliptic operators with constant second order part on the Euclidean space. We describe the coefficients in terms only of the divergence of the drift field and of curvature-like invariants, related to the minimal cost of geodesics of the associated optimal control problem. In the second part of the thesis we consider the variation of a smooth volume along a geodesic. The structure of the manifold is induced by a quadratic Hamiltonian and the geodesic in described as the projection of the Hamiltonian flow. We find an expansion similar to the classical Riemannian one. It depends on the curvature operator associated to the Hamiltonian, on the symbol of the geodesic and on a new metric-measure invariant determined by the symbol of the geodesic and by the given volume. %I SISSA %G en %1 35290 %2 Mathematics %4 -1 %# MAT/05 %$ Submitted by epaoli@sissa.it (epaoli@sissa.it) on 2015-11-26T08:47:31Z No. of bitstreams: 1 Paoli_thesis.pdf: 1061974 bytes, checksum: d273a57f7bf44214d5fc30460ece686a (MD5) %0 Report %D 2015 %T The wave equation on domains with cracks growing on a prescribed path: existence, uniqueness, and continuous dependence on the data %A Gianni Dal Maso %A Ilaria Lucardesi %X Given a bounded open set $\Omega \subset \mathbb R^d$ with Lipschitz boundary and an increasing family $\Gamma_t$, $t\in [0,T]$, of closed subsets of $\Omega$, we analyze the scalar wave equation $\ddot{u} - div (A \nabla u) = f$ in the time varying cracked domains $\Omega\setminus\Gamma_t$. Here we assume that the sets $\Gamma_t$ are contained into a prescribed $(d-1)$-manifold of class $C^2$. Our approach relies on a change of variables: recasting the problem on the reference configuration $\Omega\setminus \Gamma_0$, we are led to consider a hyperbolic problem of the form $\ddot{v} - div (B\nabla v) + a \cdot \nabla v - 2 b \cdot \nabla \dot{v} = g$ in $\Omega \setminus \Gamma_0$. Under suitable assumptions on the regularity of the change of variables that transforms $\Omega\setminus \Gamma_t$ into $\Omega\setminus \Gamma_0$, we prove existence and uniqueness of weak solutions for both formulations. Moreover, we provide an energy equality, which gives, as a by-product, the continuous dependence of the solutions with respect to the cracks. %G en %U http://urania.sissa.it/xmlui/handle/1963/34629 %1 34832 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by lucardes@sissa.it (lucardes@sissa.it) on 2015-10-12T09:08:37Z No. of bitstreams: 1 DM-Luc-15-SISSA.pdf: 376913 bytes, checksum: bfdcf0975c25c9366acb4195e0f08e79 (MD5) %0 Journal Article %D 2014 %T An Abstract Nash–Moser Theorem and Quasi-Periodic Solutions for NLW and NLS on Compact Lie Groups and Homogeneous Manifolds %A Massimiliano Berti %A Livia Corsi %A Michela Procesi %X We prove an abstract implicit function theorem with parameters for smooth operators defined on scales of sequence spaces, modeled for the search of quasi-periodic solutions of PDEs. The tame estimates required for the inverse linearised operators at each step of the iterative scheme are deduced via a multiscale inductive argument. The Cantor-like set of parameters where the solution exists is defined in a non inductive way. This formulation completely decouples the iterative scheme from the measure theoretical analysis of the parameters where the small divisors non-resonance conditions are verified. As an application, we deduce the existence of quasi-periodic solutions for forced NLW and NLS equations on any compact Lie group or manifold which is homogeneous with respect to a compact Lie group, extending previous results valid only for tori. A basic tool of harmonic analysis is the highest weight theory for the irreducible representations of compact Lie groups. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34651 %1 34858 %2 Mathematics %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-20T12:19:54Z No. of bitstreams: 1 preprint2014.pdf: 549502 bytes, checksum: 4896c2df9fba6a09abb33941adb07837 (MD5) %R 10.1007/s00220-014-2128-4 %0 Journal Article %D 2014 %T Achieving unanimous opinions in signed social networks %A Claudio Altafini %A Gabriele Lini %X Being able to predict the outcome of an opinion forming process is an important problem in social network theory. However, even for linear dynamics, this becomes a difficult task as soon as non-cooperative interactions are taken into account. Such interactions are naturally modeled as negative weights on the adjacency matrix of the social network. In this paper we show how the Perron-Frobenius theorem can be used for this task also beyond its standard formulation for cooperative systems. In particular we show how it is possible to associate the achievement of unanimous opinions with the existence of invariant cones properly contained in the positive orthant. These cases correspond to signed adjacency matrices having the eventual positivity property, i.e., such that in sufficiently high powers all negative entries have disappeared. More generally, we show how for social networks the achievement of a, possibily non-unanimous, opinion can be associated to the existence of an invariant cone fully contained in one of the orthants of n. %I Institute of Electrical and Electronics Engineers Inc. %G en %U http://urania.sissa.it/xmlui/handle/1963/34935 %1 35137 %2 Mathematics %4 1 %$ Approved for entry into archive by Maria Pia Calandra (calapia@sissa.it) on 2015-11-06T12:24:07Z (GMT) No. of bitstreams: 0 %R 10.1109/ECC.2014.6862161 %0 Journal Article %D 2014 %T Adler-Gelfand-Dickey approach to classical W-algebras within the theory of Poisson vertex algebras %A Alberto De Sole %A Victor G. Kac %A Daniele Valeri %X We put the Adler-Gelfand-Dickey approach to classical W-algebras in the framework of Poisson vertex algebras. We show how to recover the bi-Poisson structure of the KP hierarchy, together with its generalizations and reduction to the N-th KdV hierarchy, using the formal distribution calculus and the lambda-bracket formalism. We apply the Lenard-Magri scheme to prove integrability of the corresponding hierarchies. We also give a simple proof of a theorem of Kupershmidt and Wilson in this framework. Based on this approach, we generalize all these results to the matrix case. In particular, we find (non-local) bi-Poisson structures of the matrix KP and the matrix N-th KdV hierarchies, and we prove integrability of the N-th matrix KdV hierarchy. %I SISSA %G eng %U http://hdl.handle.net/1963/7242 %0 Report %D 2014 %T Approximate Hermitian-Yang-Mills structures on semistable principal Higgs bundles %A Ugo Bruzzo %A Beatriz Grana-Otero %K Principal (Higgs) bundles, semistability, approximate Hermitian-Yang-Mills structures, Kaehler metrics %X We generalize the Hitchin-Kobayashi correspondence between semistability and the existence of approximate Hermitian-Yang-Mills structures to the case of principal Higgs bundles. We prove that a principal Higgs bundle $\fE$ on a compact K\"ahler manifold, with structure group a connected linear algebraic reductive group $G$, is semistable if and only if it admits an approximate Hermitian-Yang-Mills structure. %I SISSA %G en %U http://hdl.handle.net/1963/7249 %1 7287 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Ugo Bruzzo (bruzzo@sissa.it) on 2014-01-31T22:31:28Z No. of bitstreams: 1 ApprSSPrinHiggs-10.pdf: 345293 bytes, checksum: 8f5aa014820dc72ce8c40936e854f76d (MD5) %0 Journal Article %D 2014 %T Approximate Hermitian–Yang–Mills structures on semistable principal Higgs bundles %A Ugo Bruzzo %A Beatriz Grana-Otero %X We generalize the Hitchin-Kobayashi correspondence between semistability and the existence of approximate Hermitian-Yang-Mills structures to the case of principal Higgs bundles. We prove that a principal Higgs bundle on a compact Kaehler manifold, with structure group a connected linear algebraic reductive group, is semistable if and only if it admits an approximate Hermitian-Yang-Mills structure. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34645 %1 34849 %2 Mathematics %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-14T16:50:03Z No. of bitstreams: 1 preprint2014.pdf: 191569 bytes, checksum: 33ef336bcd23cb79195af6fc13704f62 (MD5) %R 10.1007/s10455-014-9433-1 %0 Journal Article %D 2014 %T Approximate Hitchin-Kobayashi correspondence for Higgs G-bundles %A Ugo Bruzzo %A Beatriz Graña Otero %X We announce a result about the extension of the Hitchin-Kobayashi correspondence to principal Higgs bundles. A principal Higgs bundle on a compact Kähler manifold, with structure group a connected linear algebraic reductive group, is semistable if and only if it admits an approximate Hermitian-Yang-Mills structure. %I World Scientific Publishing %G en %U http://urania.sissa.it/xmlui/handle/1963/35095 %1 35350 %2 Mathematics %4 1 %$ Approved for entry into archive by Maria Pia Calandra (calapia@sissa.it) on 2015-12-02T12:29:37Z (GMT) No. of bitstreams: 0 %R 10.1142/S0219887814600159 %0 Journal Article %D 2014 %T Buckling dynamics of a solvent-stimulated stretched elastomeric sheet %A Alessandro Lucantonio %A Matthieu Roché %A Paola Nardinocchi %A Howard A. Stone %X When stretched uniaxially, a thin elastic sheet may exhibit buckling. The occurrence of buckling depends on the geometrical properties of the sheet and the magnitude of the applied strain. Here we show that an elastomeric sheet initially stable under uniaxial stretching can destabilize when exposed to a solvent that swells the elastomer. We demonstrate experimentally and computationally that the features of the buckling pattern depend on the magnitude of stretching, and this observation offers a new way for controlling the shape of a swollen homogeneous thin sheet. %I Royal Society of Chemistry %G en %U http://urania.sissa.it/xmlui/handle/1963/34967 %1 35197 %2 Physics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-11-10T09:50:41Z No. of bitstreams: 1 preprint2014.pdf: 2111018 bytes, checksum: 568652d2ca6c44cdad3e520342c8042d (MD5) %R 10.1039/c3sm52941j %0 Journal Article %J Communications in Mathematical Physics 331, nr. 2 (2014) 623-676 %D 2014 %T Classical W-algebras and generalized Drinfeld-Sokolov hierarchies for minimal and short nilpotents %A Alberto De Sole %A Victor G. Kac %A Daniele Valeri %X We derive explicit formulas for lambda-brackets of the affine classical W-algebras attached to the minimal and short nilpotent elements of any simple Lie algebra g. This is used to compute explicitly the first non-trivial PDE of the corresponding intgerable generalized Drinfeld-Sokolov hierarchies. It turns out that a reduction of the equation corresponding to a short nilpotent is Svinolupov's equation attached to a simple Jordan algebra, while a reduction of the equation corresponding to a minimal nilpotent is an integrable Hamiltonian equation on 2h-3 functions, where h is the dual Coxeter number of g. In the case when g is sl_2 both these equations coincide with the KdV equation. In the case when g is not of type C_n, we associate to the minimal nilpotent element of g yet another generalized Drinfeld-Sokolov hierarchy. %B Communications in Mathematical Physics 331, nr. 2 (2014) 623-676 %I SISSA %G en %U http://hdl.handle.net/1963/6979 %1 6967 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Daniele Valeri (dvaleri@sissa.it) on 2013-07-13T15:27:20Z No. of bitstreams: 1 1306.1684v1.pdf: 580565 bytes, checksum: de8a5fc99d3eb9f1c4f85b4a2a6592e9 (MD5) %R 10.1007/s00220-014-2049-2 %0 Journal Article %D 2014 %T Comparison between reduced basis and stochastic collocation methods for elliptic problems %A Peng Chen %A Alfio Quarteroni %A Gianluigi Rozza %X The stochastic collocation method (Babuška et al. in SIAM J Numer Anal 45(3):1005-1034, 2007; Nobile et al. in SIAM J Numer Anal 46(5):2411-2442, 2008a; SIAM J Numer Anal 46(5):2309-2345, 2008b; Xiu and Hesthaven in SIAM J Sci Comput 27(3):1118-1139, 2005) has recently been applied to stochastic problems that can be transformed into parametric systems. Meanwhile, the reduced basis method (Maday et al. in Comptes Rendus Mathematique 335(3):289-294, 2002; Patera and Rozza in Reduced basis approximation and a posteriori error estimation for parametrized partial differential equations Version 1.0. Copyright MIT, http://augustine.mit.edu, 2007; Rozza et al. in Arch Comput Methods Eng 15(3):229-275, 2008), primarily developed for solving parametric systems, has been recently used to deal with stochastic problems (Boyaval et al. in Comput Methods Appl Mech Eng 198(41-44):3187-3206, 2009; Arch Comput Methods Eng 17:435-454, 2010). In this work, we aim at comparing the performance of the two methods when applied to the solution of linear stochastic elliptic problems. Two important comparison criteria are considered: (1), convergence results of the approximation error; (2), computational costs for both offline construction and online evaluation. Numerical experiments are performed for problems from low dimensions O (1) to moderate dimensions O (10) and to high dimensions O (100). The main result stemming from our comparison is that the reduced basis method converges better in theory and faster in practice than the stochastic collocation method for smooth problems, and is more suitable for large scale and high dimensional stochastic problems when considering computational costs. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34727 %1 34916 %2 Mathematics %4 1 %$ Approved for entry into archive by Maria Pia Calandra (calapia@sissa.it) on 2015-10-26T11:39:14Z (GMT) No. of bitstreams: 0 %R 10.1007/s10915-013-9764-2 %0 Journal Article %J Annals of Nuclear Energy %D 2014 %T Comparison of a Modal Method and a Proper Orthogonal Decomposition approach for multi-group time-dependent reactor spatial kinetics %A Alberto Sartori %A Davide Baroli %A Antonio Cammi %A Davide Chiesa %A Lelio Luzzi %A Roberto R. Ponciroli %A Ezio Previtali %A Marco E. Ricotti %A Gianluigi Rozza %A Monica Sisti %XIn this paper, two modelling approaches based on a Modal Method (MM) and on the Proper Orthogonal Decomposition (POD) technique, for developing a control-oriented model of nuclear reactor spatial kinetics, are presented and compared. Both these methods allow developing neutronics description by means of a set of ordinary differential equations. The comparison of the outcomes provided by the two approaches focuses on the capability of evaluating the reactivity and the neutron flux shape in different reactor configurations, with reference to a TRIGA Mark II reactor. The results given by the POD-based approach are higher-fidelity with respect to the reference solution than those computed according to the MM-based approach, in particular when the perturbation concerns a reduced region of the core. If the perturbation is homogeneous throughout the core, the two approaches allow obtaining comparable accuracy results on the quantities of interest. As far as the computational burden is concerned, the POD approach ensures a better efficiency rather than direct Modal Method, thanks to the ability of performing a longer computation in the preprocessing that leads to a faster evaluation during the on-line phase.

%B Annals of Nuclear Energy %I Elsevier %V 71 %P 229 %8 09/2014 %G en %U http://urania.sissa.it/xmlui/handle/1963/35039 %1 35270 %2 Physics %4 1 %$ Approved for entry into archive by Maria Pia Calandra (calapia@sissa.it) on 2015-11-18T12:07:02Z (GMT) No. of bitstreams: 0 %& 217 %R 10.1016/j.anucene.2014.03.043 %0 Journal Article %D 2014 %T Conformal invariants from nodal sets. I. negative eigenvalues and curvature prescription %A Rod R. Gover %A Yaiza Canzani %A Dmitry Jakobson %A Raphaël Ponge %A Andrea Malchiodi %X In this paper, we study conformal invariants that arise from nodal sets and negative eigenvalues of conformally covariant operators; more specifically, the Graham, Jenne, Mason, and Sparling (GJMS) operators, which include the Yamabe and Paneitz operators. We give several applications to curvature prescription problems. We establish a version in conformal geometry of Courant's Nodal Domain Theorem. We also show that on any manifold of dimension n≥3, there exist many metrics for which our invariants are nontrivial. We prove that the Yamabe operator can have an arbitrarily large number of negative eigenvalues on any manifold of dimension n≥3. We obtain similar results for some higher order GJMS operators on some Einstein and Heisenberg manifolds. We describe the invariants arising from the Yamabe and Paneitz operators associated to left-invariant metrics on Heisenberg manifolds. Finally, in Appendix, the second named author and Andrea Malchiodi study the Q-curvature prescription problems for noncritical Q-curvatures. %I Oxford University Press %G en %U http://urania.sissa.it/xmlui/handle/1963/35128 %1 35366 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-12-02T16:09:57Z No. of bitstreams: 1 preprint2014.pdf: 356671 bytes, checksum: 20e817f9f20d9c72d717e04f94f86bd9 (MD5) %R 10.1093/imrn/rns295 %0 Journal Article %D 2014 %T On conjugate times of LQ optimal control problems %A Andrei A. Agrachev %A Luca Rizzi %A Pavel Silveira %K Optimal control, Lagrange Grassmannian, Conjugate point %X Motivated by the study of linear quadratic optimal control problems, we consider a dynamical system with a constant, quadratic Hamiltonian, and we characterize the number of conjugate times in terms of the spectrum of the Hamiltonian vector field $\vec{H}$. We prove the following dichotomy: the number of conjugate times is identically zero or grows to infinity. The latter case occurs if and only if $\vec{H}$ has at least one Jordan block of odd dimension corresponding to a purely imaginary eigenvalue. As a byproduct, we obtain bounds from below on the number of conjugate times contained in an interval in terms of the spectrum of $\vec{H}$. %I Springer %G en %U http://hdl.handle.net/1963/7227 %1 7261 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-12-03T08:50:15Z No. of bitstreams: 1 1311.2009v1.pdf: 401341 bytes, checksum: 5c32a0e534e70539f1823acdad41ddca (MD5) %R 10.1007/s10883-014-9251-6 %0 Journal Article %D 2014 %T Constrained BV functions on double coverings for Plateau's type problems %A Stefano Amato %A Giovanni Bellettini %A Maurizio Paolini %X We link Brakke's "soap films" covering construction with the theory of finite perimeter sets, in order to study Plateau's problem without fixing a priori the topology of the solution. The minimization is set up in the class of $BV$ functions defined on a double covering space of the complement of an $(n − 2)$-dimensional smooth compact manifold $S$ without boundary. The main novelty of our approach stands in the presence of a suitable constraint on the fibers, which couples together the covering sheets. The model allows to avoid all issues concerning the presence of the boundary $S$. The constraint is lifted in a natural way to Sobolev spaces, allowing also an approach based on $Γ$-convergence theory. %G en_US %1 7597 %$ Submitted by Stefano Amato (samato@sissa.it) on 2014-12-12T07:20:56Z No. of bitstreams: 1 bvcovering_gen.pdf: 520748 bytes, checksum: 7b3d78994ff2d2ae5cbbe87eaa5f0777 (MD5) %0 Journal Article %D 2014 %T A correction and an extension of Stampacchia's work on the geometric BVP %A Giovanni Vidossich %X G. Stampacchia introduced the geometric boundary value problem for ODEs in his doctoral thesis and published four papers related to it. Here we point out that the proof of his last theorem on the subject is incorrect and we provide a substitute for it as well as a generalizations of some of his earlier results. %I Advanced Nonlinear Studies %G en %U http://urania.sissa.it/xmlui/handle/1963/35023 %1 35263 %2 Mathematics %4 1 %$ Approved for entry into archive by Maria Pia Calandra (calapia@sissa.it) on 2015-11-17T10:33:42Z (GMT) No. of bitstreams: 0 %0 Journal Article %D 2014 %T Crawling on directional surfaces %A Paolo Gidoni %A Giovanni Noselli %A Antonio DeSimone %X In this paper we study crawling locomotion based on directional frictional interactions, namely, frictional forces that are sensitive to the sign of the sliding velocity. Surface interactions of this type are common in biology, where they arise from the presence of inclined hairs or scales at the crawler/substrate interface, leading to low resistance when sliding ‘along the grain’, and high resistance when sliding ‘against the grain’. This asymmetry can be exploited for locomotion, in a way analogous to what is done in cross-country skiing (classic style, diagonal stride). We focus on a model system, namely, a continuous one-dimensional crawler and provide a detailed study of the motion resulting from several strategies of shape change. In particular, we provide explicit formulae for the displacements attainable with reciprocal extensions and contractions (breathing), or through the propagation of extension or contraction waves. We believe that our results will prove particularly helpful for the study of biological crawling motility and for the design of bio-mimetic crawling robots. %I Elsevier %G en %U http://urania.sissa.it/xmlui/handle/1963/34450 %1 34593 %2 Mathematics %$ Submitted by gnoselli@sissa.it (gnoselli@sissa.it) on 2015-03-07T17:53:32Z No. of bitstreams: 1 directional_interactions_crawlers.pdf: 568854 bytes, checksum: 2a0beb61813ef3b1e6ddb3fd6f5c842e (MD5) %R 10.1016/j.ijnonlinmec.2014.01.012 %0 Journal Article %D 2014 %T Critical points of the Moser-Trudinger functional on a disk %A Andrea Malchiodi %A Luca Martinazzi %X On the 2-dimensional unit disk $B_1$ we study the Moser-Trudinger functional $$E(u)=\int_{B_1}(e^{u^2}-1)dx, u\in H^1_0(B_1)$$ and its restrictions to $M_\Lambda:=\{u \in H^1_0(B_1):\|u\|^2_{H^1_0}=\Lambda\}$ for $\Lambda>0$. We prove that if a sequence $u_k$ of positive critical points of $E|_{M_{\Lambda_k}}$ (for some $\Lambda_k>0$) blows up as $k\to\infty$, then $\Lambda_k\to 4\pi$, and $u_k\to 0$ weakly in $H^1_0(B_1)$ and strongly in $C^1_{\loc}(\bar B_1\setminus\{0\})$. Using this we also prove that when $\Lambda$ is large enough, then $E|_{M_\Lambda}$ has no positive critical point, complementing previous existence results by Carleson-Chang, M. Struwe and Lamm-Robert-Struwe. %I European Mathematical Society %G en %U http://hdl.handle.net/1963/6560 %1 6487 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Andrea Malchiodi (malchiod@sissa.it) on 2013-03-14T10:24:49Z No. of bitstreams: 1 1203.1077v1.pdf: 218315 bytes, checksum: 7e4a2900b082b373371033ed0196f5de (MD5) %R 10.4171/JEMS/450 %0 Thesis %D 2014 %T The curvature of optimal control problems with applications to sub-Riemannian geometry %A Luca Rizzi %K Sub-Riemannian geometry %X Optimal control theory is an extension of the calculus of variations, and deals with the optimal behaviour of a system under a very general class of constraints. This field has been pioneered by the group of mathematicians led by Lev Pontryagin in the second half of the 50s and nowadays has countless applications to the real worlds (robotics, trains, aerospace, models for human behaviour, human vision, image reconstruction, quantum control, motion of self-propulsed micro-organism). In this thesis we introduce a novel definition of curvature for an optimal control problem. In particular it works for any sub-Riemannian and sub-Finsler structure. Related problems, such as comparison theorems for sub-Riemannian manifolds, LQ optimal control problem and Popp's volume and are also investigated. %I SISSA %G en %U http://hdl.handle.net/1963/7321 %1 7367 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Luca Rizzi (lrizzi@sissa.it) on 2014-05-23T12:10:38Z No. of bitstreams: 1 main.pdf: 2357698 bytes, checksum: 7283fc7a064552ee4709b0dfccddf2b8 (MD5) %] Introduction 1) The curvature of optimal control problems 2) Comparison theorems for conjugate points in sub-Riemannian geometry 3) On conjugate times of LQ optimal control problems 4) A formula for Popp's volume in sub-Riemannian geometry %0 Journal Article %J Procedia Engineering %D 2014 %T Curvature-adapted Remeshing of CAD Surfaces %A Franco Dassi %A Andrea Mola %A Hang Si %B Procedia Engineering %I Elsevier {BV} %V 82 %P 253–265 %G eng %U https://doi.org/10.1016/j.proeng.2014.10.388 %R 10.1016/j.proeng.2014.10.388 %0 Journal Article %D 2014 %T Curvature-adapted remeshing of CAD surfaces %A Franco Dassi %A Andrea Mola %A Hang Si %X A common representation of surfaces with complicated topology and geometry is through composite parametric surfaces as is the case for most CAD modelers. A challenging problem is how to generate a mesh of such a surface that well approximates the geometry of the surface, preserves its topology and important geometric features, and contains nicely shaped elements. In this work, we present an optimization-based surface remeshing method that is able to satisfy many of these requirements simultaneously. This method is inspired by the recent work of Lévy and Bonneel (Proc. 21th International Meshing Roundtable, October 2012), which embeds a smooth surface into a high-dimensional space and remesh it uniformly in that embedding space. Our method works directly in the 3d spaces and uses an embedding space in R6 to evaluate mesh size and mesh quality. It generates a curvatureadapted anisotropic surface mesh that well represents the geometry of the surface with a low number of elements. We illustrate our approach through various examples. %I Elsevier %G en %U http://urania.sissa.it/xmlui/handle/1963/34994 %1 35220 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-11-11T16:19:16Z No. of bitstreams: 1 art2014.pdf: 3913220 bytes, checksum: ba78b55b28c0eed195d2abc48bd7ca4b (MD5) %R 10.1016/j.proeng.2014.10.388 %0 Report %D 2014 %T The decomposition of optimal transportation problems with convex cost %A Stefano Bianchini %A Mauro Bardelloni %I SISSA %G en_US %U http://hdl.handle.net/1963/7433 %1 7527 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-09-22T14:16:35Z No. of bitstreams: 1 sissa _45_2014_MATE.pdf: 893572 bytes, checksum: c4334710f599da624c2e1cfb56aac415 (MD5) %0 Thesis %D 2014 %T The decomposition of optimal transportation problems with convex cost %A Mauro Bardelloni %K Optimal Transportation %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/7475 %1 7570 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by Mauro Bardelloni (mbarde@sissa.it) on 2014-10-27T10:15:30Z No. of bitstreams: 1 Bardelloni-thesis.pdf: 1162347 bytes, checksum: f2b57d7f3054afe4fae1c207b090121f (MD5) %0 Journal Article %D 2014 %T A density result for GSBD and its application to the approximation of brittle fracture energies %A Flaviana Iurlano %X We present an approximation result for functions u: Ω → ℝ^n belonging to the space GSBD(Ω) ∩ L2(Ω, ℝn) with e(u) square integrable and Hn-1(Ju) finite. The approximating functions uk are piecewise continuous functions such that uk → u in (Formula Presented). As an application, we provide the extension to the vector-valued case of the Γ-convergence result in GSBV(Ω) proved by Ambrosio and Tortorelli (Commun Pure Appl Math 43:999-1036, 1990; Boll. Un. Mat. Ital. B (7) 6:105-123, 1992). %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34647 %1 34851 %2 Mathematics %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-14T17:02:41Z No. of bitstreams: 1 preprint2014.pdf: 543013 bytes, checksum: 1d1170449f762ffdaf48812b31671bc2 (MD5) %R 10.1007/s00526-013-0676-7 %0 Journal Article %D 2014 %T Dirac operators on noncommutative principal circle bundles %A Andrzej Sitarz %A Alessandro Zucca %A Ludwik Dabrowski %X We study spectral triples over noncommutative principal U(1)-bundles of arbitrary dimension and a compatibility condition between the connection and the Dirac operator on the total space and on the base space of the bundle. Examples of low-dimensional noncommutative tori are analyzed in more detail and all connections found that are compatible with an admissible Dirac operator. Conversely, a family of new Dirac operators on the noncommutative tori, which arise from the base-space Dirac operator and a suitable connection is exhibited. These examples are extended to the theta-deformed principal U(1)-bundle S 3 θ → S2. %I World Scientific Publishing %G en %U http://urania.sissa.it/xmlui/handle/1963/35125 %1 35363 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-12-02T15:58:16Z No. of bitstreams: 1 preprint2014.pdf: 282573 bytes, checksum: 862ea930b67b00c451a0c6f093be973d (MD5) %R 10.1142/S0219887814500121 %0 Journal Article %J Communications in Mathematical Physics 331, nr. 3 (2014) 1155-1190 %D 2014 %T Dirac reduction for Poisson vertex algebras %A Alberto De Sole %A Victor G. Kac %A Daniele Valeri %X We construct an analogue of Dirac's reduction for an arbitrary local or non-local Poisson bracket in the general setup of non-local Poisson vertex algebras. This leads to Dirac's reduction of an arbitrary non-local Poisson structure. We apply this construction to an example of a generalized Drinfeld-Sokolov hierarchy. %B Communications in Mathematical Physics 331, nr. 3 (2014) 1155-1190 %I SISSA %G en %U http://hdl.handle.net/1963/6980 %1 6968 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Daniele Valeri (dvaleri@sissa.it) on 2013-07-13T15:28:44Z No. of bitstreams: 1 1306.6589v1.pdf: 417586 bytes, checksum: 261351372e0d72d5e2d46b6664f19fd4 (MD5) %R 10.1007/s00220-014-2103-0 %0 Journal Article %D 2014 %T Discrete one-dimensional crawlers on viscous substrates: achievable net displacements and their energy cost %A Giovanni Noselli %A Amabile Tatone %A Antonio DeSimone %K Cell migration %X We study model one-dimensional crawlers, namely, model mechanical systems that can achieve self-propulsion by controlled shape changes of their body (extension or contraction of portions of the body), thanks to frictional interactions with a rigid substrate. We evaluate the achievable net displacement and the related energetic cost for self-propulsion by discrete crawlers (i.e., whose body is made of a discrete number of contractile or extensile segments) moving on substrates with either a Newtonian (linear) or a Bingham-type (stick-slip) rheology. Our analysis is aimed at constructing the basic building blocks towards an integrative, multi-scale description of crawling cell motility. %I Elsevier %G en %U http://urania.sissa.it/xmlui/handle/1963/34449 %1 34591 %2 Mathematics %$ Submitted by gnoselli@sissa.it (gnoselli@sissa.it) on 2015-03-07T17:44:40Z No. of bitstreams: 1 N-link_crawlers.pdf: 1005838 bytes, checksum: 685d5b41e7de190ec65c60090d397f93 (MD5) %R 10.1016/j.mechrescom.2013.10.023 %0 Report %D 2014 %T Donagi–Markman cubic for the generalised Hitchin system %A Ugo Bruzzo %A Peter Dalakov %K Generalized Hitchin system, Donagi-Markman cubic, algebraically completely integrable systems, moduli space of Higgs G-bundles %X Donagi and Markman (1993) have shown that the infinitesimal period map for an algebraic completely integrable Hamiltonian system (ACIHS) is encoded in a section of the third symmetric power of the cotangent bundle to the base of the system. For the ordinary Hitchin system the cubic is given by a formula of Balduzzi and Pantev. We show that the Balduzzi–Pantev formula holds on maximal rank symplectic leaves of the G-generalised Hitchin system. %G en %U http://hdl.handle.net/1963/7253 %1 7294 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Ugo Bruzzo (bruzzo@sissa.it) on 2014-02-17T15:50:22Z No. of bitstreams: 1 bruzzo-dalakov-fin-2.pdf: 461019 bytes, checksum: 99e7b1cb6cd4f6f5d5fbfaa1d2d35880 (MD5) %0 Report %D 2014 %T Dynamics on a graph as the limit of the dynamics on a "fat graph" %A Gianfausto Dell'Antonio %A Alessandro Michelangeli %X We discuss how the vertex boundary conditions for the dynamics of a quantum particle constrained on a graph emerge in the limit of the dynamics of a particle in a tubular region around the graph (\fat graph") when the transversal section of this region shrinks to zero. We give evidence of the fact that if the limit dynamics exists and is induced by the Laplacian on the graph with certain self-adjoint boundary conditions, such conditions are determined by the possible presence of a zero energy resonance on the fat graph. Pictorially, one may say that in the shrinking limit the resonance acts as a bridge connecting the boundary values at the vertex along the different rays. %I SISSA %G en_US %U http://urania.sissa.it/xmlui/handle/1963/7485 %1 7598 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-12-12T13:16:15Z No. of bitstreams: 1 sissa-preprint-69-2014-mate.pdf: 137454 bytes, checksum: 4d4571bd97df46ee020c81057ce78620 (MD5) %0 Journal Article %D 2014 %T Editorial %A Ciro Ciliberto %A Gianni Dal Maso %A Pasquale Vetro %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34712 %1 34926 %2 Mathematics %4 1 %$ Approved for entry into archive by Maria Pia Calandra (calapia@sissa.it) on 2015-10-26T10:50:12Z (GMT) No. of bitstreams: 0 %R 10.1007/s12215-014-0172-8 %0 Journal Article %D 2014 %T An effective model for nematic liquid crystal composites with ferromagnetic inclusions %A Maria Carme Calderer %A Antonio DeSimone %A Dmitry Golovaty %A Alexander Panchenko %X Molecules of a nematic liquid crystal respond to an applied magnetic field by reorienting themselves in the direction of the field. Since the dielectric anisotropy of a nematic is small, it takes relatively large fields to elicit a significant liquid crystal response. The interaction may be enhanced in colloidal suspensions of ferromagnetic particles in a liquid crystalline matrix- ferronematics-as proposed by Brochard and de Gennes in 1970. The ability of these particles to align with the field and simultaneously cause reorientation of the nematic molecules greatly increases the magnetic response of the mixture. Essentially the particles provide an easy axis of magnetization that interacts with the liquid crystal via surface anchoring. We derive an expression for the effective energy of ferronematic in the dilute limit, that is, when the number of particles tends to infinity while their total volume fraction tends to zero. The total energy of the mixture is assumed to be the sum of the bulk elastic liquid crystal contribution, the anchoring energy of the liquid crystal on the surfaces of the particles, and the magnetic energy of interaction between the particles and the applied magnetic field. The homogenized limiting ferronematic energy is obtained rigorously using a variational approach. It generalizes formal expressions previously reported in the physical literature. %I Society for Industrial and Applied Mathematics Publications %G en %U http://urania.sissa.it/xmlui/handle/1963/34940 %1 35194 %2 Physics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-11-09T09:28:26Z No. of bitstreams: 1 preprint2014.pdf: 284611 bytes, checksum: ef4123b4aefb1a36fa198c1207a6f021 (MD5) %R 10.1137/130910348 %0 Report %D 2014 %T An efficient computational framework for reduced basis approximation and a posteriori error estimation of parametrized Navier-Stokes flows %A Andrea Manzoni %K Reduced Basis Method, parametrized Navier-Stokes equations, steady incompressible fluids, a posteriori error estimation, approximation stability %X We present the current Reduced Basis framework for the efficient numerical approximation of parametrized steady Navier-Stokes equations. We have extended the existing setting developed in the last decade (see e.g. [Deparis, Veroy & Patera, Quarteroni & Rozza] to more general affine and nonaffine parametrizations (such as volume-based techniques), to a simultaneous velocity-pressure error estimates and to a fully decoupled Offline/Online procedure in order to speedup the solution of the reduced-order problem. This is particularly suitable for real-time and many-query contexts, which are both part of our final goal. Furthermore, we present an efficient numerical implementation for treating nonlinear advection terms in a convenient way. A residual-based a posteriori error estimation with respect to a truth, full-order Finite Element approximation is provided for joint pressure/velocity errors, according to the Brezzi-Rappaz-Raviart stability theory. To do this, we take advantage of an extension of the Successive Constraint Method for the estimation of stability factors and of a suitable fixed-point algorithm for the approximation of Sobolev embedding constants. Finally, we present some numerical test cases, in order to show both the approximation properties and the computational efficiency of the derived framework. %G en %1 7291 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Andrea Manzoni (amanzoni@sissa.it) on 2014-02-12T17:36:11Z No. of bitstreams: 1 AM_2014_M2AN_preprint.pdf: 5678588 bytes, checksum: 9589729cb84fffc5229b4b071e5e69fb (MD5) %0 Journal Article %J International Journal of Computational Fluid Dynamics %D 2014 %T Efficient geometrical parametrisation techniques of interfaces for reduced-order modelling: application to fluid–structure interaction coupling problems %A Forti, D. %A Rozza, G. %X We present some recent advances and improvements in shape parametrisation techniques of interfaces for reduced-order modelling with special attention to fluid–structure interaction problems and the management of structural deformations, namely, to represent them into a low-dimensional space (by control points). This allows to reduce the computational effort, and to significantly simplify the (geometrical) deformation procedure, leading to more efficient and fast reduced-order modelling applications in this kind of problems. We propose an efficient methodology to select the geometrical control points for the radial basis functions based on a modal greedy algorithm to improve the computational efficiency in view of more complex fluid–structure applications in several fields. The examples provided deal with aeronautics and wind engineering. %B International Journal of Computational Fluid Dynamics %V 28 %P 158–169 %G eng %R 10.1080/10618562.2014.932352 %0 Journal Article %D 2014 %T Existence and uniqueness of the gradient flow of the Entropy in the space of probability measures %A Stefano Bianchini %A Alexander Dabrowski %X After a brief introduction on gradient flows in metric spaces and on geodesically convex functionals, we give an account of the proof (following the outline of [3, 7]) of the existence and uniqueness of the gradient flow of the Entropy in the space of Borel probability measures over a compact geodesic metric space with Ricci curvature bounded from below. %I EUT Edizioni Universita di Trieste %G en %U http://urania.sissa.it/xmlui/handle/1963/34693 %1 34907 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-10-22T09:22:40Z No. of bitstreams: 1 ExUniqGFEntropy.pdf: 344636 bytes, checksum: a918d50ab5d6b9ce9cb8683238f402e6 (MD5) %0 Report %D 2014 %T Existence and uniqueness of the gradient flow of the entropy in the space of probability measures %A Stefano Bianchini %A Alexander Dabrowski %X After a brief introduction on gradient ows in metric spaces and on geodesically convex functionals, we give an account of the proof (following the outline of [3, 4]) of the existence and uniqueness of the gradient ow of the Entropy in the space of Borel probability measures over a compact geodesic metric space with Ricci curvature bounded from below. %I SISSA %G en %1 7356 %2 Mathematics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-03-19T10:46:21Z No. of bitstreams: 1 ExUniqGFEntropy.pdf: 344636 bytes, checksum: a918d50ab5d6b9ce9cb8683238f402e6 (MD5) %0 Journal Article %D 2014 %T Finite dimensional Kadomtsev-Petviashvili τ-functions. I. Finite Grassmannians %A Ferenc Balogh %A Tiago Fonseca %A John P. Harnad %X We study τ-functions of the Kadomtsev-Petviashvili hierarchy in terms of abelian group actions on finite dimensional Grassmannians, viewed as subquotients of the Hilbert space Grassmannians of Sato, Segal, and Wilson. A determinantal formula of Gekhtman and Kasman involving exponentials of finite dimensional matrices is shown to follow naturally from such reductions. All reduced flows of exponential type generated by matrices with arbitrary nondegenerate Jordan forms are derived, both in the Grassmannian setting and within the fermionic operator formalism. A slightly more general determinantal formula involving resolvents of the matrices generating the flow, valid on the big cell of the Grassmannian, is also derived. An explicit expression is deduced for the Plücker coordinates appearing as coefficients in the Schur function expansion of the τ-function. %I American Institute of Physics Inc. %G en %U http://urania.sissa.it/xmlui/handle/1963/34952 %1 35153 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-11-04T14:31:01Z No. of bitstreams: 1 preprint2014.pdf: 403949 bytes, checksum: 01d5c482538ca09d858c0586f648b196 (MD5) %R 10.1063/1.4890818 %0 Conference Proceedings %B Proceedings of the 24th International Ocean and Polar Engineering Conference, Busan, 2014 %D 2014 %T A fully nonlinear potential model for ship hydrodynamics directly interfaced with CAD data structures %A Andrea Mola %A Luca Heltai %A Antonio DeSimone %K ship hydrodynamics %X We present a model for ship hydrodynamics simulations currently under development at SISSA. The model employs potential flow theory and fully nonlinear free surface boundary conditions. The spatial discretization of the equations is performed by means of a collocation BEM. This gives rise to a Differential Algbraic Equations (DAE) system, solved using an implicit BDF scheme to time advance the solution. The model has been implemented into a C++ software able to automatically generate the computational grids from the CAD geometry of the hull. Numerical results on Kriso KCS and KVLCC2 hulls are presented and discussed. %B Proceedings of the 24th International Ocean and Polar Engineering Conference, Busan, 2014 %I SISSA %G en %1 7357 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Luca Heltai (heltai@sissa.it) on 2014-03-22T15:00:37Z No. of bitstreams: 1 MolaHeltaiDeSimone2014.pdf: 1241007 bytes, checksum: 1a56d909a08f1f470c7efc14018e37f8 (MD5) %0 Book Section %B Separated representations and PGD-based model reduction : fundamentals and applications %D 2014 %T Fundamentals of Reduced Basis Method for problems governed by parametrized PDEs and applications %A Gianluigi Rozza %K reduced basis method, linear elasticity, heat transfer, error bounds, parametrized PDEs %XIn this chapter we consider Reduced Basis (RB) approximations of parametrized Partial Differential Equations (PDEs). The the idea behind RB is to decouple the generation and projection stages (Offline/Online computational procedures) of the approximation process in order to solve parametrized PDEs in a fast, inexpensive and reliable way. The RB method, especially applied to 3D problems, allows great computational savings with respect to the classical Galerkin Finite Element (FE) Method. The standard FE method is typically ill suited to (i) iterative contexts like optimization, sensitivity analysis and many-queries in general, and (ii) real time evaluation. We consider for simplicity coercive PDEs. We discuss all the steps to set up a RB approximation, either from an analytical and a numerical point of view. Then we present an application of the RB method to a steady thermal conductivity problem in heat transfer with emphasis on geometrical and physical parameters.

%B Separated representations and PGD-based model reduction : fundamentals and applications %S CISM International Centre for Mechanical Sciences %I Springer %C Wien %V 554 %G eng %& 4 %R 10.1007/978-3-7091-1794-1_4 %0 Thesis %D 2014 %T Geometry and analysis of control-affine systems: motion planning, heat and Schrödinger evolution %A Dario Prandi %K control theory %X This thesis is dedicated to two problems arising from geometric control theory, regarding control-affine systems $\dot q= f_0(q)+\sum_{j=1}^m u_j f_j(q)$, where $f_0$ is called the drift. In the first part we extend the concept of complexity of non-admissible trajectories, well understood for sub-Riemannian systems, to this more general case, and find asymptotic estimates. In order to do this, we also prove a result in the same spirit as the Ball-Box theorem for sub-Riemannian systems, in the context of control-affine systems equipped with the L1 cost. Then, in the second part of the thesis, we consider a family of 2-dimensional driftless control systems. For these, we study how the set where the control vector fields become collinear affects the diffusion dynamics. More precisely, we study whether solutions to the heat and Schrödinger equations associated with this Laplace-Beltrami operator are able to cross this singularity, and how its the presence affects the spectral properties of the operator, in particular under a magnetic Aharonov–Bohm-type perturbation. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/7474 %1 7576 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by dprandi@sissa.it (dprandi@sissa.it) on 2014-10-28T17:03:22Z No. of bitstreams: 1 thesis_SISSA.pdf: 2610057 bytes, checksum: b1f6802988c3d34412407d628c7c1963 (MD5) %0 Journal Article %D 2014 %T Global Structure of Admissible BV Solutions to Piecewise Genuinely Nonlinear, Strictly Hyperbolic Conservation Laws in One Space Dimension %A Stefano Bianchini %A Lei Yu %X The paper describes the qualitative structure of an admissible BV solution to a strictly hyperbolic system of conservation laws whose characteristic families are piecewise genuinely nonlinear. More precisely, we prove that there are a countable set of points Θ and a countable family of Lipschitz curves T{script} such that outside T{script} ∪ Θ the solution is continuous, and for all points in T{script}{set minus}Θ the solution has left and right limit. This extends the corresponding structural result in [7] for genuinely nonlinear systems. An application of this result is the stability of the wave structure of solution w.r.t. -convergence. The proof is based on the introduction of subdiscontinuities of a shock, whose behavior is qualitatively analogous to the discontinuities of the solution to genuinely nonlinear systems. %I Taylor & Francis %G en %U http://urania.sissa.it/xmlui/handle/1963/34694 %1 34908 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-10-22T09:34:23Z No. of bitstreams: 1 global structure of solutions to PWGN hyperbolic conservation laws.pdf: 452219 bytes, checksum: 85bd51fc08fa53a087cee8aec2b9544a (MD5) %R 10.1080/03605302.2013.775153 %0 Report %D 2014 %T Globally stable quasistatic evolution for a coupled elastoplastic-damage model %A Vito Crismale %K Variational models %X We show the existence of globally stable quasistatic evolutions for a material model with elastoplasticity and incomplete damage, in small strain assumptions. The main feature of our model is that the scalar internal variable which describes the damage a ects both the elastic tensor and the plastic yield surface. It is also possible to require that the history of plastic strain up to the current state influences the future evolution of damage. %I SISSA %G en %U http://hdl.handle.net/1963/7324 %1 7374 %2 Mathematics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-06-05T06:00:38Z No. of bitstreams: 1 QSEvoPlas.pdf: 405510 bytes, checksum: 742d878ed01a16f9c88ce0c6311d88fa (MD5) %0 Report %D 2014 %T The Gysin Sequence for Quantum Lens Spaces %A Francesca Arici %A Simon Brain %A Giovanni Landi %X We define quantum lens spaces as `direct sums of line bundles' and exhibit them as `total spaces' of certain principal bundles over quantum projective spaces. For each of these quantum lens spaces we construct an analogue of the classical Gysin sequence in K-theory. We use the sequence to compute the K-theory of the quantum lens spaces, in particular to give explicit geometric representatives of their K-theory classes. These representatives are interpreted as `line bundles' over quantum lens spaces and generically define `torsion classes'. We work out explicit examples of these classes. %G en %U http://hdl.handle.net/1963/7246 %1 7288 %2 Mathematics %4 1 %$ Submitted by Francesca Arici (farici@sissa.it) on 2014-01-30T18:32:27Z No. of bitstreams: 1 1401.6788v1.pdf: 343718 bytes, checksum: eb153f01a7f9c0e5941b36d633b1f63a (MD5) %0 Thesis %D 2014 %T Holomorphically symplectic varieties with Prym Lagrangian fibrations %A Tommaso Matteini %K Holomorphically symplectic varieties %X The thesis presents a construction of singular holomorphically symplectic varieties as Lagrangian fibrations. They are relative compactified Prym varieties associated to curves on symplectic surfaces with an antisymplectic involution. They are identified with the fixed locus of a symplectic involution on singular moduli spaces of sheaves of dimension 1. An explicit example, giving a singular irreducible symplectic 6-fold without symplectic resolutions, is described for a K3 surface which is the double cover of a cubic surface. In the case of abelian surfaces, a variation of this construction is studied to get irreducible symplectic varieties: relative compactified 0-Prym varieties. A partial classification result is obtained for involutions without fixed points: either the 0-Prym variety is birational to an irreducible symplectic variety of K3[n]-type, or it does not admit symplectic resolutions. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/7434 %1 7511 %2 Mathematics %4 1 %# MAT/03 %$ Submitted by Tommaso Matteini (tommatte@sissa.it) on 2014-09-15T12:25:24Z No. of bitstreams: 1 PhDThesis.pdf: 910291 bytes, checksum: 263baffb058a78779fea853930868b2e (MD5) %0 Report %D 2014 %T Homogenization of functional with linear growth in the context of A-quasiconvexity %A Jose Matias %A Marco Morandotti %A Pedro M. Santos %X This work deals with the homogenization of functionals with linear growth in the context of A-quasiconvexity. A representation theorem is proved, where the new integrand function is obtained by solving a cell problem where the coupling between homogenization and the A-free condition plays a crucial role. This result extends some previous work to the linear case, thus allowing for concentration effects. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/7436 %1 7528 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-10-07T06:20:26Z No. of bitstreams: 1 Mat-Mor-San-14.pdf: 352795 bytes, checksum: de708e4c922915ea1f523eb23165cb83 (MD5) %0 Journal Article %D 2014 %T Homology computation for a class of contact structures on T3 %A Ali Maalaoui %A Vittorio Martino %X We consider a family of tight contact forms on the three-dimensional torus and we compute the relative Contact Homology by using the variational theory of critical points at infinity. We will also show local stability. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34649 %1 34856 %2 Mathematics %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-20T12:08:36Z No. of bitstreams: 1 preprint2014.pdf: 371632 bytes, checksum: abec6bf1b85cb6034662ab217f97c4b8 (MD5) %R 10.1007/s00526-013-0648-y %0 Journal Article %J Comptes Rendus Mathematique %D 2014 %T An improvement on geometrical parameterizations by transfinite maps %A Jäggli, C. %A Iapichino, L. %A Rozza, G. %X We present a method to generate a non-affine transfinite map from a given reference domain to a family of deformed domains. The map is a generalization of the Gordon-Hall transfinite interpolation approach. It is defined globally over the reference domain. Once we have computed some functions over the reference domain, the map can be generated by knowing the parametric expressions of the boundaries of the deformed domain. Being able to define a suitable map from a reference domain to a desired deformation is useful for the management of parameterized geometries. %B Comptes Rendus Mathematique %V 352 %P 263–268 %G eng %R 10.1016/j.crma.2013.12.017 %0 Journal Article %D 2014 %T Infinite-dimensional Frobenius manifolds underlying the Toda lattice hierarchy %A Chaozhong Wu %A Dafeng Zuo %X Following the approach of Carlet et al. (2011) [9], we construct a class of infinite-dimensional Frobenius manifolds underlying the Toda lattice hierarchy, which are defined on the space of pairs of meromorphic functions with possibly higher-order poles at the origin and at infinity. We also show a connection between these infinite-dimensional Frobenius manifolds and the finite-dimensional Frobenius manifolds on the orbit space of extended affine Weyl groups of type A defined by Dubrovin and Zhang. %I Elsevier %G en %U http://urania.sissa.it/xmlui/handle/1963/35026 %1 35264 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-11-17T10:32:31Z No. of bitstreams: 1 preprint2014.pdf: 358025 bytes, checksum: ef718fc5b61dfb8c0e0bd874196cfd13 (MD5) %R 10.1016/j.aim.2014.01.013 %0 Report %D 2014 %T Integrability of Dirac reduced bi-Hamiltonian equations %A Alberto De Sole %A Victor G. Kac %A Daniele Valeri %X First, we give a brief review of the theory of the Lenard-Magri scheme for a non-local bi-Poisson structure and of the theory of Dirac reduction. These theories are used in the remainder of the paper to prove integrability of three hierarchies of bi-Hamiltonian PDE's, obtained by Dirac reduction from some generalized Drinfeld-Sokolov hierarchies. %I SISSA %G en %U http://hdl.handle.net/1963/7247 %1 7286 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Daniele Valeri (dvaleri@sissa.it) on 2014-01-24T09:47:51Z No. of bitstreams: 1 1401.6006v1.pdf: 249123 bytes, checksum: 3b83fabf790160e10ecb05aa89251970 (MD5) %0 Report %D 2014 %T An irreducible symplectic orbifold of dimension 6 with a Lagrangian Prym fibration %A Tommaso Matteini %K Irreducible symplectic variety, Lagrangian fibration, Prym variety, automorphism of symplectic varieties %X A new example of an irreducible symplectic variety of dimension 6, with only finite quotient singularities, is described as a relative compactified Prymian of a family of genus 4 curves with involution. It is associated to a K3 surface which is a double cover of a cubic surface. It has a natural Lagrangian fibration in abelian 3-folds with polarization type (1,1,2). It does not admit any symplectic resolution. %G en %1 7360 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Tommaso Matteini (tommatte@sissa.it) on 2014-04-07T21:56:09Z No. of bitstreams: 1 1403.5523v1.pdf: 263523 bytes, checksum: 3476aafd392b9871807ce18a89b857f4 (MD5) %0 Journal Article %D 2014 %T On an isomonodromy deformation equation without the Painlevé property %A Boris Dubrovin %A Andrei Kapaev %X We show that the fourth order nonlinear ODE which controls the pole dynamics in the general solution of equation $P_I^2$ compatible with the KdV equation exhibits two remarkable properties: 1) it governs the isomonodromy deformations of a $2\times2$ matrix linear ODE with polynomial coefficients, and 2) it does not possesses the Painlev\'e property. We also study the properties of the Riemann--Hilbert problem associated to this ODE and find its large $t$ asymptotic solution for the physically interesting initial data. %I Maik Nauka-Interperiodica Publishing %G en %U http://hdl.handle.net/1963/6466 %1 6410 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Boris Dubrovin (dubrovin@sissa.it) on 2013-02-08T11:29:56Z No. of bitstreams: 1 1301.7211v2.pdf: 415681 bytes, checksum: f606a3b5df4b201ae37a9d6fa1b79016 (MD5) %R 10.1134/S1061920814010026 %0 Journal Article %D 2014 %T KAM for quasi-linear and fully nonlinear forced perturbations of Airy equation %A Pietro Baldi %A Massimiliano Berti %A Riccardo Montalto %X We prove the existence of small amplitude quasi-periodic solutions for quasi-linear and fully nonlinear forced perturbations of the linear Airy equation. For Hamiltonian or reversible nonlinearities we also prove their linear stability. The key analysis concerns the reducibility of the linearized operator at an approximate solution, which provides a sharp asymptotic expansion of its eigenvalues. For quasi-linear perturbations this cannot be directly obtained by a KAM iteration. Hence we first perform a regularization procedure, which conjugates the linearized operator to an operator with constant coefficients plus a bounded remainder. These transformations are obtained by changes of variables induced by diffeomorphisms of the torus and pseudo-differential operators. At this point we implement a Nash-Moser iteration (with second order Melnikov non-resonance conditions) which completes the reduction to constant coefficients. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34715 %1 34920 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-22T14:51:37Z No. of bitstreams: 1 preprint2014.pdf: 774433 bytes, checksum: 8e74e3ac1996200c204d66e5fac294a2 (MD5) %R 10.1007/s00208-013-1001-7 %0 Journal Article %J Mathematische Annalen %D 2014 %T KAM for quasi-linear and fully nonlinear forced perturbations of Airy equation %A Pietro Baldi %A Massimiliano Berti %A Riccardo Montalto %X We prove the existence of small amplitude quasi-periodic solutions for quasi-linear and fully nonlinear forced perturbations of the linear Airy equation. For Hamiltonian or reversible nonlinearities we also prove their linear stability. The key analysis concerns the reducibility of the linearized operator at an approximate solution, which provides a sharp asymptotic expansion of its eigenvalues. For quasi-linear perturbations this cannot be directly obtained by a KAM iteration. Hence we first perform a regularization procedure, which conjugates the linearized operator to an operator with constant coefficients plus a bounded remainder. These transformations are obtained by changes of variables induced by diffeomorphisms of the torus and pseudo-differential operators. At this point we implement a Nash-Moser iteration (with second order Melnikov non-resonance conditions) which completes the reduction to constant coefficients. © 2014 Springer-Verlag Berlin Heidelberg. %B Mathematische Annalen %P 1-66 %G eng %R 10.1007/s00208-013-1001-7 %0 Thesis %D 2014 %T KAM for quasi-linear and fully nonlinear perturbations of Airy and KdV equations %A Riccardo Montalto %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/7476 %1 7571 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by rmontalt@sissa.it (rmontalt@sissa.it) on 2014-10-27T10:15:33Z No. of bitstreams: 1 Tesi-Phd-Montalto-Riccardo.pdf: 1843377 bytes, checksum: b4e504e6ad1860c3d3580beb4e24efff (MD5) %0 Journal Article %J C. R. Math. Acad. Sci. Paris %D 2014 %T KAM for quasi-linear KdV %A Pietro Baldi %A Massimiliano Berti %A Riccardo Montalto %B C. R. Math. Acad. Sci. Paris %V 352 %P 603–607 %G eng %N 7-8 %0 Journal Article %D 2014 %T KAM for quasi-linear KdV %A Pietro Baldi %A Massimiliano Berti %A Riccardo Montalto %X We prove the existence and stability of Cantor families of quasi-periodic, small-amplitude solutions of quasi-linear autonomous Hamiltonian perturbations of KdV. %I Elsevier %G en %U http://urania.sissa.it/xmlui/handle/1963/35067 %1 35302 %2 Mathematics %4 1 %$ Approved for entry into archive by Maria Pia Calandra (calapia@sissa.it) on 2015-11-30T15:30:40Z (GMT) No. of bitstreams: 0 %R 10.1016/j.crma.2014.04.012 %0 Journal Article %J Arch. Ration. Mech. Anal. %D 2014 %T KAM for reversible derivative wave equations %A Massimiliano Berti %A Luca Biasco %A Michela Procesi %B Arch. Ration. Mech. Anal. %V 212 %P 905–955 %G eng %N 3 %0 Journal Article %D 2014 %T KAM for Reversible Derivative Wave Equations %A Massimiliano Berti %A Luca Biasco %A Michela Procesi %X We prove the existence of Cantor families of small amplitude, analytic, linearly stable quasi-periodic solutions of reversible derivative wave equations. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34646 %1 34850 %2 Mathematics %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-14T16:55:00Z No. of bitstreams: 1 preprint2014.pdf: 620515 bytes, checksum: d1d981f350e63c9906f793bcfe66e972 (MD5) %R 10.1007/s00205-014-0726-0 %0 Journal Article %D 2014 %T Laplace equation in a domain with a rectilinear crack: higher order derivatives of the energy with respect to the crack length %A Gianni Dal Maso %A Gianluca Orlando %A Rodica Toader %K cracked domains, energy release rate, higher order derivatives, asymptotic expansion of solutions %X We consider the weak solution of the Laplace equation in a planar domain with a straight crack, prescribing a homogeneous Neumann condition on the crack and a nonhomogeneous Dirichlet condition on the rest of the boundary. For every k we express the k-th derivative of the energy with respect to the crack length in terms of a finite number of coefficients of the asymptotic expansion of the solution near the crack tip and of a finite number of other parameters, which only depend on the shape of the domain. %I SISSA %G en %U http://hdl.handle.net/1963/7271 %1 7316 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Gianni Dal Maso (dalmaso@sissa.it) on 2014-03-11T15:17:50Z No. of bitstreams: 1 DM-Orl-Toa-sissa.pdf: 251851 bytes, checksum: 59273a217a11dcfc5a9ed89d2c34c6cd (MD5) %R 10.1007/s00030-014-0291-0 %0 Book Section %D 2014 %T Lecture notes on gradient flows and optimal transport %A Sara Daneri %A Giuseppe Savarè %X We present a short overview on the strongest variational formulation for gradient flows of geodesically λ-convex functionals in metric spaces, with applications to diffusion equations in Wasserstein spaces of probability measures. These notes are based on a series of lectures given by the second author for the Summer School "Optimal transportation: Theory and applications" in Grenoble during the week of June 22-26, 2009. %I Cambridge University Press %G en %U http://urania.sissa.it/xmlui/handle/1963/35093 %1 35348 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-12-02T11:28:52Z No. of bitstreams: 1 preprint2014.pdf: 448708 bytes, checksum: b8b01c6463b81dc26c42c74009c43406 (MD5) %R 10.1017/CBO9781107297296 %0 Journal Article %D 2014 %T Legendre duality on hypersurfaces in Kähler manifolds %A Vittorio Martino %X We give a sufficient condition on real strictly Levi-convex hypersurfaces M, embedded in four-dimensional Kähler manifolds V , such that Legendre duality can be performed. We consider the contact form onM whose kernel is the restriction of the holomorphic tangent space of V and show that if there exists a Legendrian Killing vector field v, then the dual form β(̇) := d(v, ̇) is a contact form on M with the same orientation than theta. %I Walter de Gruyter and Co. %G en %U http://urania.sissa.it/xmlui/handle/1963/34777 %1 34998 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-27T17:37:38Z No. of bitstreams: 1 preprint2014.pdf: 98700 bytes, checksum: 1187e3e70cd12ba31a32c4be8491bd32 (MD5) %R 10.1515/advgeom-2014-0016 %0 Journal Article %D 2014 %T Lipschitz continuous viscosity solutions for a class of fully nonlinear equations on lie groups %A Vittorio Martino %A Annamaria Montanari %X In this paper, we prove existence and uniqueness of Lipschitz continuous viscosity solutions for Dirichlet problems involving a class a fully non-linear operators on Lie groups. In particular, we consider the elementary symmetric functions of the eigenvalues of the Hessian built with left-invariant vector fields. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34699 %1 34910 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-22T10:28:16Z No. of bitstreams: 1 preprint2014.pdf: 418666 bytes, checksum: 959eed7adb8eeecee6c733f5ad7a136c (MD5) %R 10.1007/s12220-012-9332-2 %0 Journal Article %D 2014 %T Local and global minimality results for a nonlocal isoperimetric problem on R^N %A Marco Bonacini %A Riccardo Cristoferi %K Nonlocal isoperimetric problem %X We consider a nonlocal isoperimetric problem defined in the whole space R^N, whose nonlocal part is given by a Riesz potential with exponent $\alpha\in(0, N-1)$. We show that critical configurations with positive second variation are local minimizers and satisfy a quantitative inequality with respect to the L^1-norm. This criterion provides the existence of a (explicitly determined) critical threshold determining the interval of volumes for which the ball is a local minimizer, and allows to address several global minimality issues. %I SIAM Publications %G en %U http://hdl.handle.net/1963/6984 %1 6976 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Marco Bonacini (mbonacin@sissa.it) on 2013-07-19T15:56:58Z No. of bitstreams: 1 boncri_fin.pdf: 567997 bytes, checksum: a24d4e9e6bbd6f176558b4d007dba6e3 (MD5) %R 10.1137/130929898 %0 Journal Article %D 2014 %T Local behavior of fractional p-minimizers %A Agnese Di Castro %A Tuomo Kuusi %A Giampiero Palatucci %K fractional Sobolev spaces %XWe extend the De Giorgi-Nash Moser theory to nonlocal, possibly degerate integro-differential operators

%I SISSA %G en %1 7301 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Giampiero Palatucci (palatucc@sissa.it) on 2014-03-03T08:54:40Z No. of bitstreams: 1 DKP.pdf: 459581 bytes, checksum: 58cf9e0f905a3932505ab467eefd39e9 (MD5) %0 Journal Article %D 2014 %T On the Lp-differentiability of certain classes of functions %A Giovanni Alberti %A Stefano Bianchini %A Gianluca Crippa %X We prove the Lp-differentiability at almost every point for convolution products on ℝd of the form K*μ, where μ is bounded measure and K is a homogeneous kernel of degree 1-d. From this result we derive the Lp-differentiability for vector fields on R d whose curl and divergence are measures, and also for vector fields with bounded deformation. %I European Mathematical Society %G en %U http://urania.sissa.it/xmlui/handle/1963/34695 %1 34909 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-10-22T09:44:25Z No. of bitstreams: 1 Alberti_Bianchini_50_M.pdf: 253000 bytes, checksum: 06381747f80814ced325966adefdec91 (MD5) %R 10.4171/rmi/782 %0 Journal Article %D 2014 %T Maximal generalized solution of eikonal equation %A Sandro Zagatti %X We study the Dirichlet problem for the eikonal equation: 1/2 |∇u(x)|^2-a(x)=0 in Ω u(x)=(x) on Ω, without continuity assumptions on the map a(.). We find a class of maps a(.) contained in the space L∞(Ω) for which the problem admits a (maximal) generalized solution, providing a generalization of the notion of viscosity solution. %I Elsevier %G en %U http://urania.sissa.it/xmlui/handle/1963/34642 %1 34846 %2 Mathematics %4 1 %$ Approved for entry into archive by Maria Pia Calandra (calapia@sissa.it) on 2015-10-21T08:38:44Z (GMT) No. of bitstreams: 0 %R 10.1016/j.jde.2014.04.001 %0 Journal Article %D 2014 %T Minimal Liouville gravity correlation numbers from Douglas string equation %A Alexander Belavin %A Boris Dubrovin %A Baur Mukhametzhanov %X We continue the study of $(q,p)$ Minimal Liouville Gravity with the help of Douglas string equation. We generalize the results of \cite{Moore:1991ir}, \cite{Belavin:2008kv}, where Lee-Yang series $(2,2s+1)$ was studied, to $(3,3s+p_0)$ Minimal Liouville Gravity, where $p_0=1,2$. We demonstrate that there exist such coordinates $\tau_{m,n}$ on the space of the perturbed Minimal Liouville Gravity theories, in which the partition function of the theory is determined by the Douglas string equation. The coordinates $\tau_{m,n}$ are related in a non-linear fashion to the natural coupling constants $\lambda_{m,n}$ of the perturbations of Minimal Lioville Gravity by the physical operators $O_{m,n}$. We find this relation from the requirement that the correlation numbers in Minimal Liouville Gravity must satisfy the conformal and fusion selection rules. After fixing this relation we compute three- and four-point correlation numbers when they are not zero. The results are in agreement with the direct calculations in Minimal Liouville Gravity available in the literature \cite{Goulian:1990qr}, \cite{Zamolodchikov:2005sj}, \cite{Belavin:2006ex}. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34588 %1 34795 %2 Physics %4 2 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-09-28T14:45:32Z No. of bitstreams: 1 art2014.pdf: 914777 bytes, checksum: 6f6d70a301b22d993393d16ad5abef80 (MD5) %R 10.1007/JHEP01(2014)156 %0 Journal Article %D 2014 %T Model Order Reduction in Fluid Dynamics: Challenges and Perspectives %A Toni Lassila %A Andrea Manzoni %A Alfio Quarteroni %A Gianluigi Rozza %X This chapter reviews techniques of model reduction of fluid dynamics systems. Fluid systems are known to be difficult to reduce efficiently due to several reasons. First of all, they exhibit strong nonlinearities - which are mainly related either to nonlinear convection terms and/or some geometric variability - that often cannot be treated by simple linearization. Additional difficulties arise when attempting model reduction of unsteady flows, especially when long-term transient behavior needs to be accurately predicted using reduced order models and more complex features, such as turbulence or multiphysics phenomena, have to be taken into consideration. We first discuss some general principles that apply to many parametric model order reduction problems, then we apply them on steady and unsteady viscous flows modelled by the incompressible Navier-Stokes equations. We address questions of inf-sup stability, certification through error estimation, computational issues and-in the unsteady case - long-time stability of the reduced model. Moreover, we provide an extensive list of literature references. %I Springer %G en %1 34923 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-22T15:11:51Z No. of bitstreams: 1 preprint2014.pdf: 287014 bytes, checksum: b195410aa3f63643829ed25f1adb6520 (MD5) %R 10.1007/978-3-319-02090-7_9 %0 Journal Article %D 2014 %T A modular spectral triple for κ-Minkowski space %A Marco Matassa %X We present a spectral triple for κ-Minkowski space in two dimensions. Starting from an algebra naturally associated to this space, a Hilbert space is built using a weight which is invariant under the κ-Poincaré algebra. The weight satisfies a KMS condition and its associated modular operator plays an important role in the construction. This forces us to introduce two ingredients which have a modular flavour: the first is a twisted commutator, used to obtain a boundedness condition for the Dirac operator, and the second is a weight replacing the usual operator trace, used to measure the growth of the resolvent of the Dirac operator. We show that, under some assumptions related to the symmetries and the classical limit, there is a unique Dirac operator and automorphism such that the twisted commutator is bounded. Then, using the weight mentioned above, we compute the spectral dimension associated to the spectral triple and find that is equal to the classical dimension. Finally we briefly discuss the introduction of a real structure. %I Elsevier %G en %U http://urania.sissa.it/xmlui/handle/1963/34895 %1 35180 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-11-04T16:52:19Z No. of bitstreams: 1 preprint2014.pdf: 371387 bytes, checksum: 5ec9ef2cc02f42dd114bf8fc40bcd6ec (MD5) %R 10.1016/j.geomphys.2013.10.023 %0 Report %D 2014 %T Motility of a Model Bristle-Bot: a Theoretical Analysis. %A Giancarlo Cicconofri %A Antonio DeSimone %X Bristle-bots are legged robots that can be easily made out of a toothbrush head and a small vibrating engine. Despite their simple appearance, the mechanism enabling them to propel themselves by exploiting friction with the substrate is far from trivial. Numerical experiments on a model bristle-bot have been able to reproduce such a mechanism revealing, in addition, the ability to switch direction of motion by varying the vibration frequency. This paper provides a detailed account of these phenomena through a fully analytical treatment of the model. The equations of motion are solved through an expansion in terms of a properly chosen small parameter. The convergence of the expansion is rigorously proven. In addition, the analysis delivers formulas for the average velocity of the robot and for the frequency at which the direction switch takes place. A quantitative description of the mechanism for the friction modulation underlying the motility of the bristle-bot is also provided. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/7465 %1 7573 %$ Submitted by cicconof@sissa.it (cicconof@sissa.it) on 2014-10-28T11:15:54Z No. of bitstreams: 1 BristleBot.pdf: 137903 bytes, checksum: 6ad934c41a27ec663d5c9284ea75e4ed (MD5) %0 Journal Article %D 2014 %T N = 2 Quiver Gauge Theories on A-type ALE Spaces %A Ugo Bruzzo %A Francesco Sala %A Richard J. Szabo %X We survey and compare recent approaches to the computation of the partition functions and correlators of chiral BPS observables in N = 2 gauge theories on ALE spaces based on quiver varieties and the minimal resolution Xk of the Ak-1 toric singularity C2/Zk, in light of their recently conjectured duality with two-dimensional coset conformal field theories. We review and elucidate the rigorous constructions of gauge theories for a particular family of ALE spaces, using their relation to the cohomology of moduli spaces of framed torsion-free sheaves on a suitable orbifold compactification of Xk. We extend these computations to generic N = 2 superconformal quiver gauge theories, obtaining in these instances new constraints on fractional instanton charges, a rigorous proof of the Nekrasov master formula, and new quantizations of Hitchin systems based on the underlying Seiberg–Witten geometry. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34719 %1 34918 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-22T12:43:35Z No. of bitstreams: 1 preprint2014.pdf: 715288 bytes, checksum: aa2d57d1d2ee3b6602bdcef73696035c (MD5) %R 10.1007/s11005-014-0734-x %0 Journal Article %D 2014 %T New results on Gamma-limits of integral functionals %A Nadia Ansini %A Gianni Dal Maso %A Caterina Ida Zeppieri %K Gamma-convergence %I Elsevier %G en %U http://hdl.handle.net/1963/5880 %1 5745 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-05-30T12:48:08Z No. of bitstreams: 1 03M_2012_Ansini.pdf: 262251 bytes, checksum: 4e0dd5c07ab75bd2da8aa462f2ae8f0f (MD5) %R 10.1016/j.anihpc.2013.02.005 %0 Thesis %D 2014 %T Non-commutative integration for spectral triples associated to quantum groups %A Marco Matassa %K Non-commutative geometry %X This thesis is dedicated to the study of non-commutative integration, in the sense of spectral triples, for some non-commutative spaces associated to quantum groups. %I SISSA %G en %1 7363 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Marco Matassa (mmatassa@sissa.it) on 2014-04-28T08:04:56Z No. of bitstreams: 1 Thesis (with corrections).pdf: 1129467 bytes, checksum: 77aa801082828a7b5b3fc10070f06319 (MD5) %0 Journal Article %D 2014 %T Nonsingular Isogeometric Boundary Element Method for Stokes Flows in 3D %A Luca Heltai %A Marino Arroyo %A Antonio DeSimone %K Isogeometric Analysis %X Isogeometric analysis (IGA) is emerging as a technology bridging Computer Aided Geometric Design (CAGD), most commonly based on Non-Uniform Rational B-Splines (NURBS) surfaces, and engineering analysis. In finite element and boundary element isogeometric methods (FE-IGA and IGA-BEM), the NURBS basis functions that de- scribe the geometry define also the approximation spaces. In the FE-IGA approach, the surfaces generated by the CAGD tools need to be extended to volumetric descriptions, a major open problem in 3D. This additional passage can be avoided in principle when the partial differential equations to be solved admit a formulation in terms of bound- ary integral equations, leading to Boundary Element Isogeometric Analysis (IGA-BEM). The main advantages of such an approach are given by the dimensionality reduction of the problem (from volumetric-based to surface-based), by the fact that the interface with CAGD tools is direct, and by the possibility to treat exterior problems, where the computational domain is infinite. By contrast, these methods produce system matrices which are full, and require the integration of singular kernels. In this paper we address the second point and propose a nonsingular formulation of IGA-BEM for 3D Stokes flows, whose convergence is carefully tested numerically. Standard Gaussian quadrature rules suffice to integrate the boundary integral equations, and carefully chosen known exact solutions of the interior Stokes problem are used to correct the resulting matrices, extending the work by Klaseboer et al. [27] to IGA-BEM. %I Elsevier %G en %U http://hdl.handle.net/1963/6326 %1 6250 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Luca Heltai (heltai@sissa.it) on 2012-12-03T08:19:28Z No. of bitstreams: 1 isogeo_stokes.pdf: 732320 bytes, checksum: 224ef57de6c49f03db0afaccdcb234f9 (MD5) %R 10.1016/j.cma.2013.09.017 %0 Journal Article %D 2014 %T Pfaffian representations of cubic surfaces %A Fabio Tanturri %X Let K be a field of characteristic zero. We describe an algorithm which requires a homogeneous polynomial F of degree three in K[x0,x1,x2,x3] and a zero a of F in P3 K and ensures a linear Pfaffian representation of V(F) with entries in K[x0,x1,x2,x3], under mild assumptions on F and a. We use this result to give an explicit construction of (and to prove the existence of) a linear Pfaffian representation of V (F), with entries in K′[x0,x1,x2,x3], being K′ an algebraic extension of K of degree at most six. An explicit example of such a construction is given. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34688 %1 34900 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-21T16:49:49Z No. of bitstreams: 1 preprint2014.pdf: 289546 bytes, checksum: 0a8213f23936fd48edde60b3d788f158 (MD5) %R 10.1007/s10711-012-9818-x %0 Report %D 2014 %T Pimsner algebras and Gysin sequences from principal circle actions %A Francesca Arici %A Jens Kaad %A Giovanni Landi %X A self Morita equivalence over an algebra B, given by a B-bimodule E, is thought of as a line bundle over B. The corresponding Pimsner algebra O_E is then the total space algebra of a noncommutative principal circle bundle over B. A natural Gysin-like sequence relates the KK-theories of O_E and of B. Interesting examples come from O_E a quantum lens space over B a quantum weighted projective line (with arbitrary weights). The KK-theory of these spaces is explicitly computed and natural generators are exhibited. %U http://urania.sissa.it/xmlui/handle/1963/34461 %1 34631 %2 Mathematics %4 1 %# MAT/07 %$ Submitted by Francesca Arici (farici@sissa.it) on 2015-04-02T16:28:37Z No. of bitstreams: 1 1409.5335.pdf: 352695 bytes, checksum: 2d85289a4ebe9f0e86c5540cf19b9473 (MD5) %0 Conference Paper %B The 24th International Ocean and Polar Engineering Conference %D 2014 %T Potential Model for Ship Hydrodynamics Simulations Directly Interfaced with CAD Data Structures %A Mola, Andrea %A Heltai, Luca %A De Simone, Antonio %A others %B The 24th International Ocean and Polar Engineering Conference %I International Society of Offshore and Polar Engineers %V 4 %P 815–822 %G eng %0 Journal Article %D 2014 %T Pseudo-automorphisms of positive entropy on the blowups of products of projective spaces %A Fabio Perroni %A Deqi Zhang %X We use a concise method to construct pseudo-automorphisms fn of the first dynamical degree d1(fn) > 1 on the blowups of the projective n-space for all n ≥ 2 and more generally on the blowups of products of projective spaces. These fn, for n=3 have positive entropy, and for n≥ 4 seem to be the first examples of pseudo-automorphisms with d1(fn) > 1 (and of non-product type) on rational varieties of higher dimensions. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34714 %1 34921 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-22T14:57:52Z No. of bitstreams: 1 preprint2014.pdf: 253886 bytes, checksum: 80c0805b318d2c20d9084bc5b0c31265 (MD5) %R 10.1007/s00208-013-0992-4 %0 Journal Article %D 2014 %T On a quadratic functional for scalar conservation laws %A Stefano Bianchini %A Stefano Modena %X We prove a quadratic interaction estimate for approximate solutions to scalar conservation laws obtained by the wavefront tracking approximation or the Glimm scheme. This quadratic estimate has been used in the literature to prove the convergence rate of the Glimm scheme. %I World Scientific Publishing %G en %U http://urania.sissa.it/xmlui/handle/1963/34690 %1 34903 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-10-22T08:34:56Z No. of bitstreams: 1 31M_Bianchini_Modena.pdf: 710996 bytes, checksum: 8dd1a009996ca60b6c2f1dc96bb46f43 (MD5) %R 10.1142/S0219891614500118 %0 Report %D 2014 %T Quadratic interaction functional for general systems of conservation laws %A Stefano Bianchini %A Stefano Modena %X For the Glimm scheme approximation u" to the solution of the system of conservation laws in one space dimension ut + f(u)x = 0; u(0; x) = u0(x) 2 Rn; with initial data u0 with small total variation, we prove a quadratic (w.r.t. Tot.Var.(u0)) interaction estimate, which has been used in the literature for stability and convergence results. No assumptions on the structure of the ux f are made (apart smoothness), and this estimate is the natural extension of the Glimm type interaction estimate for genuinely nonlinear systems. More precisely we obtain the following results: a new analysis of the interaction estimates of simple waves; a Lagrangian representation of the derivative of the solution, i.e. a map x(t;w) which follows the trajectory of each wave w from its creation to its cancellation; the introduction of the characteristic interval and partition for couples of waves, representing the common history of the two waves; a new functional Q controlling the variation in speed of the waves w.r.t. time. This last functional is the natural extension of the Glimm functional for genuinely nonlinear systems. The main result is that the distribution Dttx(t;w) is a measure with total mass O(1)Tot.Var.(u0)2. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/7440 %1 7536 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-10-13T08:12:23Z No. of bitstreams: 1 quadratic_fcn_general.pdf: 724766 bytes, checksum: 9e731289787357d91493cf7b5661900d (MD5) %0 Journal Article %D 2014 %T Quantum dimension and quantum projective spaces %A Marco Matassa %X We show that the family of spectral triples for quantum projective spaces introduced by D'Andrea and Dbrowski, which have spectral dimension equal to zero, can be reconsidered as modular spectral triples by taking into account the action of the element K2por its inverse. The spectral dimension computed in this sense coincides with the dimension of the classical projective spaces. The connection with the well known notion of quantum dimension of quantum group theory is pointed out. %I Institute of Mathematics %G en %U http://urania.sissa.it/xmlui/handle/1963/34764 %1 34991 %2 Physics %4 2 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-27T16:56:59Z No. of bitstreams: 1 preprint2014.pdf: 380876 bytes, checksum: 85fd2f00123c6d7110bdd8ba9731b97b (MD5) %R 10.3842/SIGMA.2014.097 %0 Journal Article %D 2014 %T Quantum gauge symmetries in noncommutative geometry %A Jyotishman Bhowmick %A Francesco D'Andrea %A Biswarup Krishna Das %A Ludwik Da̧browski %X We discuss generalizations of the notion of i) the group of unitary elements of a (real or complex) finite-dimensional C*-algebra, ii) gauge transformations and iii) (real) automorphisms in the framework of compact quantum group theory and spectral triples. The quantum analogue of these groups are defined as universal (initial) objects in some natural categories. After proving the existence of the universal objects, we discuss several examples that are of interest to physics, as they appear in the noncommutative geometry approach to particle physics: in particular, the C*-algebras M n(R), Mn(C) and Mn(H), describing the finite noncommutative space of the Einstein-Yang-Mills systems, and the algebras A F = C H M3 (C) and Aev = H H M4(C), that appear in Chamseddine-Connes derivation of the Standard Model of particle physics coupled to gravity. As a byproduct, we identify a "free" version of the symplectic group Sp.n/ (quaternionic unitary group). %I European Mathematical Society Publishing House %G en %U http://urania.sissa.it/xmlui/handle/1963/34897 %1 35182 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-11-04T16:59:52Z No. of bitstreams: 1 preprint2014.pdf: 652206 bytes, checksum: d452b46b1c285be861389dcab56e1f6e (MD5) %R 10.4171/JNCG/161 %0 Journal Article %D 2014 %T Quasi-static crack growth in hydraulic fracture %A Stefano Almi %A Gianni Dal Maso %A Rodica Toader %X We present a variational model for the quasi-static crack growth in hydraulic fracture in the framework of the energy formulation of rate-independent processes. The cracks are assumed to lie on a prescribed plane and to satisfy a very weak regularity assumption. %I Elsevier %G en %U http://urania.sissa.it/xmlui/handle/1963/34532 %1 34741 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by salmi@sissa.it (salmi@sissa.it) on 2015-09-24T08:10:23Z No. of bitstreams: 1 A-DM-T-070714.pdf: 283645 bytes, checksum: 68056ef27e9dcfa246029148c0016c0f (MD5) %R 10.1016/j.na.2014.07.009 %0 Journal Article %D 2014 %T Quasistatic evolution in perfect plasticity as limit of dynamic processes %A Gianni Dal Maso %A Riccardo Scala %K visco-elasto-plasticity %X We introduce a model of dynamic visco-elasto-plastic evolution in the linearly elastic regime and we prove an existence and uniqueness result. Then we study the limit of (a rescaled version of) the solutions when the data vary slowly. We prove that they converge, up to a subsequence, to a quasistatic evolution in perfect plasticity. %I SISSA %G en %U http://hdl.handle.net/1963/6982 %1 6975 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-07-19T11:43:19Z No. of bitstreams: 1 35M_DM-Sca-12-sissa.pdf: 320384 bytes, checksum: 40d59b05d6b292108f5fafd4bff7d6f2 (MD5) %R 10.1007/s10884-014-9409-7 %0 Report %D 2014 %T Rate-independent damage in thermo-viscoelastic materials with inertia %A Giuliano Lazzaroni %A Riccarda Rossi %A Marita Thomas %A Rodica Toader %X We present a model for rate-independent, unidirectional, partial damage in visco-elastic materials with inertia and thermal effects. The damage process is modeled by means of an internal variable, governed by a rate-independent flow rule. The heat equation and the momentum balance for the displacements are coupled in a highly nonlinear way. Our assumptions on the corresponding energy functional also comprise the case of the Ambrosio-Tortorelli phase-field model (without passage to the brittle limit). We discuss a suitable weak formulation and prove an existence theorem obtained with the aid of a (partially) decoupled time-discrete scheme and variational convergence methods. We also carry out the asymptotic analysis for vanishing viscosity and inertia and obtain a fully rate-independent limit model for displacements and damage, which is Independent of temperature. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/7444 %1 7542 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-10-15T09:00:07Z No. of bitstreams: 1 LRTT-SISSA-preprint-14_10_15.pdf: 498065 bytes, checksum: 0de0c4a77dafb5df12747fd9947cec5c (MD5) %0 Thesis %D 2014 %T Rational curves and instantons on the Fano threefold Y_5 %A Giangiacomo Sanna %K Moduli space of vector bundles %X This thesis is an investigation of the moduli spaces of instanton bundles on the Fano threefold Y_5 (a linear section of Gr(2,5)). It contains new proofs of classical facts about lines, conics and cubics on Y_5, and about linear sections of Y_5. The main original results are a Grauert-Mülich theorem for the splitting type of instantons on conics, a bound to the splitting type of instantons on lines and an SL_2-equivariant description of the moduli space in charge 2 and 3. Using these results we prove the existence of a unique SL_2-equivariant instanton of minimal charge and we show that for all instantons of charge 2 the divisor of jumping lines is smooth. In charge 3, we provide examples of instantons with reducible divisor of jumping lines. Finally, we construct a natural compactification for the moduli space of instantons of charge 3, together with a small resolution of singularities for it. %I arXiv preprint %G en %U http://urania.sissa.it/xmlui/handle/1963/7482 %1 7594 %2 Mathematics %4 1 %# MAT/02 %$ Submitted by gggsanna@sissa.it (gggsanna@sissa.it) on 2014-12-01T10:51:46Z No. of bitstreams: 1 (Official) G. Sanna - Rational curves and instantons on the Fano threefold Y5 copia.pdf: 2005901 bytes, checksum: bd001232412f102490968ba3b21e1c20 (MD5) %0 Conference Paper %B ECMI 2014 proceedings %D 2014 %T Reduced basis method for the Stokes equations in decomposable domains using greedy optimization %A Iapichino, Laura %A Quarteroni, Alfio %A Gianluigi Rozza %A Volkwein, Stefan %B ECMI 2014 proceedings %P 1–7 %G eng %0 Book %B MS&A %D 2014 %T Reduced Order Methods for Modeling and Computational Reduction %A Alfio Quarteroni %A Gianluigi Rozza %K reduced order methods, MOR, ROM, POD, RB, greedy, CFD, Numerical Analysis %XThis monograph addresses the state of the art of reduced order methods for modeling and computational reduction of complex parametrized systems, governed by ordinary and/or partial differential equations, with a special emphasis on real time computing techniques and applications in computational mechanics, bioengineering and computer graphics.

Several topics are covered, including: design, optimization, and control theory in real-time with applications in engineering; data assimilation, geometry registration, and parameter estimation with special attention to real-time computing in biomedical engineering and computational physics; real-time visualization of physics-based simulations in computer science; the treatment of high-dimensional problems in state space, physical space, or parameter space; the interactions between different model reduction and dimensionality reduction approaches; the development of general error estimation frameworks which take into account both model and discretization effects.

This book is primarily addressed to computational scientists interested in computational reduction techniques for large scale differential problems.

%B MS&A %7 1 %I Springer %C Milano %V 9 %P 334 %G eng %6 1 %R 10.1007/978-3-319-02090-7 %0 Conference Proceedings %B 22nd International Conference on Nuclear Engineering ICONE22 %D 2014 %T A reduced order model for multi-group time-dependent parametrized reactor spatial kinetics %A Alberto Sartori %A Davide Baroli %A Antonio Cammi %A Lelio Luzzi %A Gianluigi Rozza %X

In this work, a Reduced Order Model (ROM) for multigroup time-dependent parametrized reactor spatial kinetics is presented. The Reduced Basis method (built upon a high-fidelity "truth" finite element approximation) has been applied to model the neutronics behavior of a parametrized system composed by a control rod surrounded by fissile material. The neutron kinetics has been described by means of a parametrized multi-group diffusion equation where the height of the control rod (i.e., how much the rod is inserted) plays the role of the varying parameter. In order to model a continuous movement of the rod, a piecewise affine transformation based on subdomain division has been implemented. The proposed ROM is capable to efficiently reproduce the neutron flux distribution allowing to take into account the spatial effects induced by the movement of the control rod with a computational speed-up of 30000 times, with respect to the "truth" model.

%B 22nd International Conference on Nuclear Engineering ICONE22 %7 American Society Mechanical Engineering %I American Society of Mechanical Engineers (ASME) %C Prague, Czech Republic %P V005T17A048-V005T17A048 %8 07/2014 %@ 978-079184595-0 %G en %U http://urania.sissa.it/xmlui/handle/1963/35123 %1 35360 %2 Mathematics %4 1 %$ Approved for entry into archive by Maria Pia Calandra (calapia@sissa.it) on 2015-12-03T10:06:02Z (GMT) No. of bitstreams: 0 %R 10.1115/ICONE22-30707 %0 Book Section %B AIMS Series on Applied Mathematics, vol. 8 (2014): 399 - 406 %D 2014 %T Reduction on characteristics for continuous of a scalar balance law %A Giovanni Alberti %A Stefano Bianchini %A Laura Caravenna %K Method of characteristics %B AIMS Series on Applied Mathematics, vol. 8 (2014): 399 - 406 %I SISSA %G en %U http://hdl.handle.net/1963/6562 %1 6516 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-04-03T07:48:04Z No. of bitstreams: 1 Alberti_11.pdf: 330968 bytes, checksum: a5f69e2a1d0afcfe139cf17ebcaf0f2d (MD5) %0 Report %D 2014 %T Renormalization for autonomous nearly incompressible BV vector fields in 2D %A Stefano Bianchini %A Paolo Bonicatto %A N.A. Gusev %X Given a bounded autonomous vector field $b \colon \R^d \to \R^d$, we study the uniqueness of bounded solutions to the initial value problem for the related transport equation \begin{equation*} \partial_t u + b \cdot \nabla u= 0. \end{equation*} We are interested in the case where $b$ is of class BV and it is nearly incompressible. Assuming that the ambient space has dimension $d=2$, we prove uniqueness of weak solutions to the transport equation. The starting point of the present work is the result which has been obtained in [7] (where the steady case is treated). Our proof is based on splitting the equation onto a suitable partition of the plane: this technique was introduced in [3], using the results on the structure of level sets of Lipschitz maps obtained in [1]. Furthermore, in order to construct the partition, we use Ambrosio's superposition principle [4]. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/7483 %1 7596 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-12-10T11:57:30Z No. of bitstreams: 1 Bianchini-Bonicatto-Gusev.pdf: 1080138 bytes, checksum: a30cacdd6fff21a2bad334dc88ee88e4 (MD5) %0 Journal Article %D 2014 %T A Review of the Sixth Painlevé Equation %A Davide Guzzetti %X For the Painlevé VI transcendents, we provide a unitary description of the critical behaviours, the connection formulae, their complete tabulation, and the asymptotic distribution of poles close to a critical point. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34658 %1 34868 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-20T13:13:55Z No. of bitstreams: 1 preprint2014.pdf: 283505 bytes, checksum: d5f401efb5eec8b4689b090dbcca6d84 (MD5) %R 10.1007/s00365-014-9250-6 %0 Journal Article %J Proceedings of the Royal Society A 470, 20140333 (2014) %D 2014 %T A robotic crawler exploiting directional frictional interactions: experiments, numerics, and derivation of a reduced model %A Giovanni Noselli %A Antonio DeSimone %X We present experimental and numerical results for a model crawler which is able to extract net positional changes from reciprocal shape changes, i.e. ‘breathing-like’ deformations, thanks to directional, frictional interactions with a textured solid substrate, mediated by flexible inclined feet. We also present a simple reduced model that captures the essential features of the kinematics and energetics of the gait, and compare its predictions with the results from experiments and from numerical simulations. %B Proceedings of the Royal Society A 470, 20140333 (2014) %I Royal Society Publishing %G en %1 34594 %2 Mathematics %$ Submitted by gnoselli@sissa.it (gnoselli@sissa.it) on 2015-03-07T18:10:10Z No. of bitstreams: 1 bristle_crawlers.pdf: 9309327 bytes, checksum: 10f6df9814dd01c888aa9ec7836f1dff (MD5) %R 10.1098/rspa.2014.0333 %0 Journal Article %D 2014 %T SBV Regularity of Systems of Conservation Laws and Hamilton–Jacobi Equations %A Stefano Bianchini %X We review the SBV regularity for solutions to hyperbolic systems of conservation laws and Hamilton-Jacobi equations. We give an overview of the techniques involved in the proof, and a collection of related problems concludes the paper. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34691 %1 34904 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-10-22T08:51:26Z No. of bitstreams: 1 proceeding.DFDE11.pdf: 401448 bytes, checksum: 0002408d841699f963dfb817ed96e577 (MD5) %R 10.1007/s10958-014-2022-9 %0 Journal Article %D 2014 %T Second Order Asymptotic Development for the Anisotropic Cahn-Hilliard Functional %A Gianni Dal Maso %A Irene Fonseca %A Giovanni Leoni %K Gamma-convergence, Cahn-Hilliard functional, phase transitions %X The asymptotic behavior of an anisotropic Cahn-Hilliard functional with prescribed mass and Dirichlet boundary condition is studied when the parameter $\varepsilon$ that determines the width of the transition layers tends to zero. The double-well potential is assumed to be even and equal to $|s-1|^\beta$ near $s=1$, with $1<\beta<2$. The first order term in the asymptotic development by $\Gamma$-convergence is well-known, and is related to a suitable anisotropic perimeter of the interface. Here it is shown that, under these assumptions, the second order term is zero, which gives an estimate on the rate of convergence of the minimum values. %I SISSA %G en %U http://hdl.handle.net/1963/7390 %1 7439 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Gianni Dal Maso (dalmaso@sissa.it) on 2014-06-19T16:24:43Z No. of bitstreams: 1 DM-Fon-Leo-14-sissa.pdf: 409621 bytes, checksum: 40ba0baf0686b18dcd89582772f376b5 (MD5) %0 Journal Article %D 2014 %T Semiclassical limit of focusing NLS for a family of square barrier initial data %A Robert Jenkins %A Kenneth McLaughlin %X The small dispersion limit of the focusing nonlinear Schrödinger equation (NLS) exhibits a rich structure of sharply separated regions exhibiting disparate rapid oscillations at microscopic scales. The non-self-adjoint scattering problem and ill-posed limiting Whitham equations associated to focusing NLS make rigorous asymptotic results difficult. Previous studies have focused on special classes of analytic initial data for which the limiting elliptic Whitham equations are wellposed. In this paper we consider another exactly solvable family of initial data,the family of square barriers,ψ 0(x) = qχ[-L,L] for real amplitudes q. Using Riemann-Hilbert techniques, we obtain rigorous pointwise asymptotics for the semiclassical limit of focusing NLS globally in space and up to an O(1) maximal time. In particular, we show that the discontinuities in our initial data regularize by the immediate generation of genus-one oscillations emitted into the support of the initial data. To the best of our knowledge, this is the first case in which the genus structure of the semiclassical asymptotics for focusing NLS have been calculated for nonanalytic initial data. %I Wiley Periodicals %G en %U http://urania.sissa.it/xmlui/handle/1963/35066 %1 35301 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-11-30T14:57:14Z No. of bitstreams: 1 preprint2014.pdf: 5320973 bytes, checksum: 457b6c96cf2335a7c55084d85eed3dbc (MD5) %R 10.1002/cpa.21494 %0 Journal Article %D 2014 %T Shape control of active surfaces inspired by the movement of euglenids %A Marino Arroyo %A Antonio DeSimone %X We examine a novel mechanism for active surface morphing inspired by the cell body deformations of euglenids. Actuation is accomplished through in-plane simple shear along prescribed slip lines decorating the surface. Under general non-uniform actuation, such local deformation produces Gaussian curvature, and therefore leads to shape changes. Geometrically, a deformation that realizes the prescribed local shear is an isometric embedding. We explore the possibilities and limitations of this bio-inspired shape morphing mechanism, by first characterizing isometric embeddings under axisymmetry, understanding the limits of embeddability, and studying in detail the accessibility of surfaces of zero and constant curvature. Modeling mechanically the active surface as a non-Euclidean plate (NEP), we further examine the mechanism beyond the geometric singularities arising from embeddability, where mechanics and buckling play a decisive role. We also propose a non-axisymmetric actuation strategy to accomplish large amplitude bending and twisting motions of elongated cylindrical surfaces. Besides helping understand how euglenids delicately control their shape, our results may provide the background to engineer soft machines. %I Elsevier %G en %U http://urania.sissa.it/xmlui/handle/1963/35118 %1 35375 %2 Mathematics %4 1 %$ Approved for entry into archive by Maria Pia Calandra (calapia@sissa.it) on 2015-12-03T09:19:38Z (GMT) No. of bitstreams: 0 %R 10.1016/j.jmps.2013.09.017 %0 Journal Article %D 2014 %T Shape Optimization by Free-Form Deformation: Existence Results and Numerical Solution for Stokes Flows %A Francesco Ballarin %A Andrea Manzoni %A Gianluigi Rozza %A Sandro Salsa %X Shape optimization problems governed by PDEs result from many applications in computational fluid dynamics. These problems usually entail very large computational costs and require also a suitable approach for representing and deforming efficiently the shape of the underlying geometry, as well as for computing the shape gradient of the cost functional to be minimized. Several approaches based on the displacement of a set of control points have been developed in the last decades, such as the so-called free-form deformations. In this paper we present a new theoretical result which allows to recast free-form deformations into the general class of perturbation of identity maps, and to guarantee the compactness of the set of admissible shapes. Moreover, we address both a general optimization framework based on the continuous shape gradient and a numerical procedure for solving efficiently three-dimensional optimal design problems. This framework is applied to the optimal design of immersed bodies in Stokes flows, for which we consider the numerical solution of a benchmark case study from literature. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34698 %1 34914 %2 Mathematics %4 1 %$ Approved for entry into archive by Maria Pia Calandra (calapia@sissa.it) on 2015-10-22T11:24:27Z (GMT) No. of bitstreams: 0 %R 10.1007/s10915-013-9807-8 %0 Journal Article %D 2014 %T Six-dimensional supersymmetric gauge theories, quantum cohomology of instanton moduli spaces and gl(N) Quantum Intermediate Long Wave Hydrodynamics %A Giulio Bonelli %A Antonio Sciarappa %A Alessandro Tanzini %A Petr Vasko %X We show that the exact partition function of U(N) six-dimensional gauge theory with eight supercharges on C^2 x S^2 provides the quantization of the integrable system of hydrodynamic type known as gl(N) periodic Intermediate Long Wave (ILW). We characterize this system as the hydrodynamic limit of elliptic Calogero-Moser integrable system. We compute the Bethe equations from the effective gauged linear sigma model on S^2 with target space the ADHM instanton moduli space, whose mirror computes the Yang-Yang function of gl(N) ILW. The quantum Hamiltonians are given by the local chiral ring observables of the six-dimensional gauge theory. As particular cases, these provide the gl(N) Benjamin-Ono and Korteweg-de Vries quantum Hamiltonians. In the four dimensional limit, we identify the local chiral ring observables with the conserved charges of Heisenberg plus W_N algebrae, thus providing a gauge theoretical proof of AGT correspondence. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34546 %1 34771 %2 Physics %4 2 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-09-28T10:16:32Z No. of bitstreams: 1 art2014.pdf: 600092 bytes, checksum: 8a020f470fff4ce83b5d820436def73f (MD5) %R 10.1007/JHEP07(2014)141 %0 Report %D 2014 %T Some remarks on a model for rate-independent damage in thermo-visco-elastodynamics %A Giuliano Lazzaroni %A Riccarda Rossi %A Marita Thomas %A Rodica Toader %X This note deals with the analysis of a model for partial damage, where the rateindependent, unidirectional flow rule for the damage variable is coupled with the rate-dependent heat equation, and with the momentum balance featuring inertia and viscosity according to Kelvin-Voigt rheology. The results presented here combine the approach from Roubicek [1] with the methods from Lazzaroni/Rossi/Thomas/Toader [2] and extend the analysis to the setting of inhomogeneous time-dependent Dirichlet data. %I SISSA %G en %U http://urania.sissa.it/xmlui/handle/1963/7463 %1 7566 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-10-23T09:01:52Z No. of bitstreams: 1 MURPHYS_LRTT14_SISSA-preprint(1).pdf: 246259 bytes, checksum: a67369f4eab98d39fb2165d882d97592 (MD5) %0 Journal Article %D 2014 %T Some remarks on the seismic behaviour of embedded cantilevered retaining walls %A Riccardo Conti %A F. Burali D'Arezzo %A Giulia M.B. Viggiani %X This paper is a numerical investigation of the physical phenomena that control the dynamic behaviour of embedded cantilevered retaining walls. Recent experimental observations obtained from centrifuge tests have shown that embedded cantilevered retaining walls experience permanent displacements even before the acceleration reaches its critical value, corresponding to full mobilisation of the soil strength. The motivation for this work stems from the need to incorporate these observations in simplified design procedures. A parametric study was carried out on a pair of embedded cantilevered walls in dry sand, subjected to real earthquakes scaled at different values of the maximum acceleration. The results of these analyses indicate that, for the geotechnical design of the wall, the equivalent acceleration to be used in pseudo-static calculations can be related to the maximum displacement that the structure can sustain, and can be larger than the maximum acceleration expected at the site. For the structural design of the wall, it is suggested that the maximum bending moments of the wall can be computed using a realistic distribution of contact stress and a conservative value of the pseudo-static acceleration, taking into account two-dimensional amplification effects near the walls. %I Thomas Telford %G en %U http://urania.sissa.it/xmlui/handle/1963/35073 %1 35308 %2 Physics %4 2 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-11-30T17:34:56Z No. of bitstreams: 1 art2014.pdf: 1304935 bytes, checksum: 2618504941effc8eed6dddb1077d8916 (MD5) %R 10.1680/geot.13.P.031 %0 Journal Article %D 2014 %T Spontaneous division and motility in active nematic droplets %A Luca Giomi %A Antonio DeSimone %X We investigate the mechanics of an active droplet endowed with internal nematic order and surrounded by an isotropic Newtonian fluid. Using numerical simulations we demonstrate that, due to the interplay between the active stresses and the defective geometry of the nematic director, this system exhibits two of the fundamental functions of living cells: spontaneous division and motility, by means of self-generated hydrodynamic flows. These behaviors can be selectively activated by controlling a single physical parameter, namely, an active variant of the capillary number. %I American Physical Society %G en %U http://urania.sissa.it/xmlui/handle/1963/34902 %1 35107 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-11-03T14:40:44Z No. of bitstreams: 1 preprint2014.pdf: 4005398 bytes, checksum: eebaadedd03c1077a9cb2a209b5abdcc (MD5) %R 10.1103/PhysRevLett.112.147802 %0 Journal Article %J Computer Methods in Applied Mechanics and Engineering %D 2014 %T Stabilized reduced basis method for parametrized advection-diffusion PDEs %A Pacciarini, P. %A Rozza, G. %X In this work, we propose viable and efficient strategies for the stabilization of the reduced basis approximation of an advection dominated problem. In particular, we investigate the combination of a classic stabilization method (SUPG) with the Offline-Online structure of the RB method. We explain why the stabilization is needed in both stages and we identify, analytically and numerically, which are the drawbacks of a stabilization performed only during the construction of the reduced basis (i.e. only in the Offline stage). We carry out numerical tests to assess the performances of the ``double'' stabilization both in steady and unsteady problems, also related to heat transfer phenomena. %B Computer Methods in Applied Mechanics and Engineering %V 274 %P 1–18 %G eng %R 10.1016/j.cma.2014.02.005 %0 Conference Paper %B 11th World Congress on Computational Mechanics, WCCM 2014, 5th European Conference on Computational Mechanics, ECCM 2014 and 6th European Conference on Computational Fluid Dynamics, ECFD 2014 %D 2014 %T Stabilized reduced basis method for parametrized scalar advection-diffusion problems at higher Péclet number: Roles of the boundary layers and inner fronts %A Pacciarini, P. %A Rozza, G. %X Advection-dominated problems, which arise in many engineering situations, often require a fast and reliable approximation of the solution given some parameters as inputs. In this work we want to investigate the coupling of the reduced basis method - which guarantees rapidity and reliability - with some classical stabilization techiques to deal with the advection-dominated condition. We provide a numerical extension of the results presented in [1], focusing in particular on problems with curved boundary layers and inner fronts whose direction depends on the parameter. %B 11th World Congress on Computational Mechanics, WCCM 2014, 5th European Conference on Computational Mechanics, ECCM 2014 and 6th European Conference on Computational Fluid Dynamics, ECFD 2014 %P 5614–5624 %G eng %U https://infoscience.epfl.ch/record/203327/files/ECCOMAS_PP_GR.pdf %0 Report %D 2014 %T Steady nearly incompressible vector elds in 2D: chain rule and renormalization %A Stefano Bianchini %A N.A. Gusev %I SISSA %G en %1 7464 %2 Mathematics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-08-13T07:08:46Z No. of bitstreams: 1 main_stefano(1).pdf: 631783 bytes, checksum: 3ac150a4fb3cb33ebaf5273751dfdf27 (MD5) %0 Journal Article %D 2014 %T The stringy instanton partition function %A Giulio Bonelli %A Antonio Sciarappa %A Alessandro Tanzini %A Petr Vasko %X We perform an exact computation of the gauged linear sigma model associated to a D1-D5 brane system on a resolved A_1 singularity. This is accomplished via supersymmetric localization on the blown-up two-sphere. We show that in the blow-down limit C^2/Z_2 the partition function reduces to the Nekrasov partition function evaluating the equivariant volume of the instanton moduli space. For finite radius we obtain a tower of world-sheet instanton corrections, that we identify with the equivariant Gromov-Witten invariants of the ADHM moduli space. We show that these corrections can be encoded in a deformation of the Seiberg-Witten prepotential. From the mathematical viewpoint, the D1-D5 system under study displays a twofold nature: the D1-branes viewpoint captures the equivariant quantum cohomology of the ADHM instanton moduli space in the Givental formalism, and the D5-branes viewpoint is related to higher rank equivariant Donaldson-Thomas invariants of P^1 x C^2. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34589 %1 34796 %2 Physics %4 2 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-09-28T14:48:41Z No. of bitstreams: 1 art2014.pdf: 719350 bytes, checksum: 2c296ad8eb7995f07c16f6d4e36c6813 (MD5) %R 10.1007/JHEP01(2014)038 %0 Report %D 2014 %T Structure of classical (finite and affine) W-algebras %A Alberto De Sole %A Victor G. Kac %A Daniele Valeri %X First, we derive an explicit formula for the Poisson bracket of the classical finite W-algebra W^{fin}(g,f), the algebra of polynomial functions on the Slodowy slice associated to a simple Lie algebra g and its nilpotent element f. On the other hand, we produce an explicit set of generators and we derive an explicit formula for the Poisson vertex algebra structure of the classical affine W-algebra W(g,f). As an immediate consequence, we obtain a Poisson algebra isomorphism between W^{fin}(g,f) and the Zhu algebra of W(g,f). We also study the generalized Miura map for classical W-algebras. %I SISSA %G en %U http://hdl.handle.net/1963/7314 %1 7359 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Daniele Valeri (dvaleri@sissa.it) on 2014-04-04T09:52:02Z No. of bitstreams: 1 1404.0715v1.pdf: 386481 bytes, checksum: bafb532b11dfa1100008853a1f4cd543 (MD5) %0 Report %D 2014 %T Structure of entropy solutions to general scalar conservation laws in one space dimension %A Stefano Bianchini %A Lei Yu %I SISSA %G en %U http://hdl.handle.net/1963/7259 %1 7305 %2 Mathematics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-03-10T11:39:18Z No. of bitstreams: 1 Global structure of entropy solutions to scalar conservation laws.ref.pdf: 464993 bytes, checksum: 9b83b6f3f845eda8eb202f0748617756 (MD5) %0 Journal Article %D 2014 %T Swelling dynamics of a thin elastomeric sheet under uniaxial pre-stretch %A Alessandro Lucantonio %A Paola Nardinocchi %A Howard A. Stone %X It has been demonstrated experimentally that pre-stretch affects the swelling of an elastomeric membrane when it is exposed to a solvent. We study theoretically the one-dimensional swelling of a pre-stretched thin elastomeric sheet, bonded to an impermeable rigid substrate, to quantify the influence of pre-stretch. We show that the solvent uptake increases when pre-stretch increases, both at equilibrium and during the swelling transient, where it exhibits two different scaling regimes. The coupling between the solvent uptake and pre-stretch may be practically exploited to design soft actuators where the swelling-induced deformations can be controlled by varying the pre-stretch. %I American Institute of Physics %G en %U http://urania.sissa.it/xmlui/handle/1963/35113 %1 35370 %2 Physics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-12-02T16:28:53Z No. of bitstreams: 1 art2014.pdf: 777840 bytes, checksum: 2362b6250fd872264208d0d3b846a551 (MD5) %R 10.1063/1.4866576 %0 Journal Article %D 2014 %T Swelling-induced and controlled curving in layered gel beams %A Alessandro Lucantonio %A Paola Nardinocchi %A Matteo Pezzulla %X We describe swelling-driven curving in originally straight and non-homogeneous beams. We present and verify a structural model of swollen beams, based on a new point of view adopted to describe swelling-induced deformation processes in bilayered gel beams, that is based on the split of the swelling-induced deformation of the beam at equilibrium into two components, both depending on the elastic properties of the gel. The method allows us to: (i) determine beam stretching and curving, once assigned the characteristics of the solvent bath and of the non-homogeneous beam, and (ii) estimate the characteristics of non-homogeneous flat gel beams in such a way as to obtain, under free-swelling conditions, three-dimensional shapes. The study was pursued by means of analytical, semi-analytical and numerical tools; excellent agreement of the outcomes of the different techniques was found, thus confirming the strength of the method. %I Royal Society of London %G en %U http://urania.sissa.it/xmlui/handle/1963/34987 %1 35229 %2 Mathematics %4 1 %$ Approved for entry into archive by Lucio Lubiana (lubiana@sissa.it) on 2015-11-12T09:25:24Z (GMT) No. of bitstreams: 0 %R 10.1098/rspa.2014.0467 %0 Journal Article %J J. Stat. Phys 155 (2014) 1027-1071 %D 2014 %T Topological Invariants of Eigenvalue Intersections and Decrease of Wannier Functions in Graphene %A Domenico Monaco %A Gianluca Panati %K Wannier functions, Bloch bundles, conical intersections, eigenspace vorticity, pseudospin winding number, graphene %X We investigate the asymptotic decrease of the Wannier functions for the valence and conduction band of graphene, both in the monolayer and the multilayer case. Since the decrease of the Wannier functions is characterised by the structure of the Bloch eigenspaces around the Dirac points, we introduce a geometric invariant of the family of eigenspaces, baptised eigenspace vorticity. We compare it with the pseudospin winding number. For every value n∈Z of the eigenspace vorticity, we exhibit a canonical model for the local topology of the eigenspaces. With the help of these canonical models, we show that the single band Wannier function w satisfies |w(x)|≤const |x|^{−2} as |x|→∞, both in monolayer and bilayer graphene. %B J. Stat. Phys 155 (2014) 1027-1071 %I Journal of Statistical Physics %G en %1 7368 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Domenico Monaco (dmonaco@sissa.it) on 2014-05-25T14:32:44Z No. of bitstreams: 1 WannierGraphene_arXiv_v3.pdf: 618532 bytes, checksum: 975235799a61f551f3c4889727353676 (MD5) %R 10.1007/s10955-014-0918-x %0 Journal Article %D 2014 %T The topology of a subspace of the Legendrian curves on a closed contact 3-manifold %A Ali Maalaoui %A Vittorio Martino %X In this paper we study a subspace of the space of Legendrian loops and we show that the injection of this space into the full loop space is an S 1-equivariant homotopy equivalence. This space can be also seen as the space of zero Maslov index Legendrian loops and it shows up as a suitable space of variations in contact form geometry. %I Advanced Nonlinear Studies %G en %U http://urania.sissa.it/xmlui/handle/1963/35016 %1 35262 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-11-17T09:54:29Z No. of bitstreams: 1 preprint2014.pdf: 721147 bytes, checksum: 810ace1cc0879eac4e2e7b7f33a89751 (MD5) %0 Journal Article %D 2014 %T A uniqueness result for the continuity equation in two dimensions: dedicated to constantine dafermos on the occasion of his 70th birthday %A Giovanni Alberti %A Stefano Bianchini %A Gianluca Crippa %X We characterize the autonomous, divergence-free vector fields b on the plane such that the Cauchy problem for the continuity equation ∂tu +div(bu) = 0 admits a unique bounded solution (in the weak sense) for every bounded initial datum; the characterization is given in terms of a property of Sard type for the potential f associated to b. As a corollary we obtain uniqueness under the assumption that the curl of b is a measure. This result can be extended to certain nonautonomous vector fields b with bounded divergence. %I European Mathematical Society; Springer Verlag %G en %U http://urania.sissa.it/xmlui/handle/1963/34692 %1 34906 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2015-10-22T09:07:51Z No. of bitstreams: 1 Alberti_Bianchini_Crippa_52M.pdf: 318780 bytes, checksum: 556a1d21b44c58d90201b25b2c104744 (MD5) %R 10.4171/JEMS/431 %0 Thesis %D 2014 %T A variational approach to statics and dynamics of elasto-plastic systems %A Riccardo Scala %K delamination %X We prove some existence results for dynamic evolutions in elasto-plasticity and delamination. We study the limit as the data vary very slowly and prove convergence results to quasistatic evolutions. We model dislocations by mean of currents, we introduce the space of deformations in the presence of dislocations and study the graphs of these maps. We prove existence results for minimum problems. We study the properties of minimizers. %I SISSA %G en_US %U http://urania.sissa.it/xmlui/handle/1963/7471 %1 7583 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by Riccardo Scala (rscala@sissa.it) on 2014-10-29T12:04:30Z No. of bitstreams: 1 tesi.pdf: 1322338 bytes, checksum: 5fcf0395d13a0dc16eac4edaef440913 (MD5) %0 Journal Article %D 2014 %T A variational model for the quasi-static growth of fractional dimensional brittle fractures %A Simone Racca %A Rodica Toader %K Variational models %X We propose a variational model for the irreversible quasi-static evolution of brittle fractures having fractional Hausdorff dimension in the setting of two-dimensional antiplane and plane elasticity. The evolution along such irregular crack paths can be obtained as $\Gamma$-limit of evolutions along one-dimensional cracks when the fracture toughness tends to zero. %I European Mathematical Society %G en %U http://hdl.handle.net/1963/6983 %1 6973 %2 Mathematics %4 -1 %$ Submitted by Simone Racca (sracca@sissa.it) on 2013-07-18T08:39:00Z No. of bitstreams: 1 Racca_Toader.pdf: 416939 bytes, checksum: cf459548a10944037e56b7504fe60f51 (MD5) %R 10.4171/IFB/328 %0 Journal Article %D 2014 %T Vortex Partition Functions, Wall Crossing and Equivariant Gromov–Witten Invariants %A Giulio Bonelli %A Antonio Sciarappa %A Alessandro Tanzini %A Petr Vasko %X In this paper we identify the problem of equivariant vortex counting in a (2,2) supersymmetric two dimensional quiver gauged linear sigma model with that of computing the equivariant Gromov–Witten invariants of the GIT quotient target space determined by the quiver. We provide new contour integral formulae for the I and J-functions encoding the equivariant quantum cohomology of the target space. Its chamber structure is shown to be encoded in the analytical properties of the integrand. This is explained both via general arguments and by checking several key cases. We show how several results in equivariant Gromov–Witten theory follow just by deforming the integration contour. In particular, we apply our formalism to compute Gromov–Witten invariants of the C3/Zn orbifold, of the Uhlembeck (partial) compactification of the moduli space of instantons on C2, and of An and Dn singularities both in the orbifold and resolved phases. Moreover, we analyse dualities of quantum cohomology rings of holomorphic vector bundles over Grassmannians, which are relevant to BPS Wilson loop algebrae. %I Springer %G en %U http://urania.sissa.it/xmlui/handle/1963/34652 %1 34859 %2 Physics %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-10-20T12:25:03Z No. of bitstreams: 1 preprint2014.pdf: 652465 bytes, checksum: 355132ee06625045b6adf8b1f4862533 (MD5) %R 10.1007/s00220-014-2193-8 %0 Journal Article %D 2014 %T A weighted empirical interpolation method: A priori convergence analysis and applications %A Peng Chen %A Alfio Quarteroni %A Gianluigi Rozza %X We extend the classical empirical interpolation method [M. Barrault, Y. Maday, N.C. Nguyen and A.T. Patera, An empirical interpolation method: application to efficient reduced-basis discretization of partial differential equations. Compt. Rend. Math. Anal. Num. 339 (2004) 667-672] to a weighted empirical interpolation method in order to approximate nonlinear parametric functions with weighted parameters, e.g. random variables obeying various probability distributions. A priori convergence analysis is provided for the proposed method and the error bound by Kolmogorov N-width is improved from the recent work [Y. Maday, N.C. Nguyen, A.T. Patera and G.S.H. Pau, A general, multipurpose interpolation procedure: the magic points. Commun. Pure Appl. Anal. 8 (2009) 383-404]. We apply our method to geometric Brownian motion, exponential Karhunen-Loève expansion and reduced basis approximation of non-affine stochastic elliptic equations. We demonstrate its improved accuracy and efficiency over the empirical interpolation method, as well as sparse grid stochastic collocation method. %I EDP Sciences %G en %U http://urania.sissa.it/xmlui/handle/1963/35021 %1 35253 %2 Mathematics %4 1 %# MAT/05 %$ Approved for entry into archive by Lucio Lubiana (lubiana@sissa.it) on 2015-11-17T10:26:06Z (GMT) No. of bitstreams: 0 %R 10.1051/m2an/2013128 %0 Journal Article %D 2014 %T Weighted quantile correlation test for the logistic family %A Ferenc Balogh %A Éva Krauczi %X We summarize the results of investigating the asymptotic behavior of the weighted quantile correlation tests for the location-scale family associated to the logistic distribution. Explicit representations of the limiting distribution are given in terms of integrals of weighted Brownian bridges or alternatively as infinite series of independent Gaussian random variables. The power of this test and the test for the location logistic family against some alternatives are demonstrated by numerical simulations. %I University of Szeged %G en %U http://urania.sissa.it/xmlui/handle/1963/35025 %1 35261 %2 Mathematics %4 1 %$ Submitted by gfeltrin@sissa.it (gfeltrin@sissa.it) on 2015-11-17T09:50:18Z No. of bitstreams: 1 preprint2014.pdf: 364753 bytes, checksum: 77f35846fb1cee29a66ca18ff89d5331 (MD5) %R 10.14232/actasm-013-809-8 %0 Report %D 2014 %T Where best to place a Dirichlet condition in an anisotropic membrane? %A Paolo Tilli %A Davide Zucco %X We study a shape optimization problem for the first eigenvalue of an elliptic operator in divergence form, with non constant coefficients, over a fixed domain $\Omega$. Dirichlet conditions are imposed along $\partial\Omega$ and, in addition, along a set $\Sigma$ of prescribed length ($1$-dimensional Hausdorff measure). We look for the best shape and position for the supplementary Dirichlet region $\Sigma$ in order to maximize the first eigenvalue. We characterize the limit distribution of the optimal sets, as their prescribed length tends to infinity, via $\Gamma$-convergence. %I SISSA %G en_US %U http://urania.sissa.it/xmlui/handle/1963/7481 %1 7592 %$ Submitted by dzucco@sissa.it (dzucco@sissa.it) on 2014-11-07T16:09:28Z No. of bitstreams: 1 Tilli_Zucco_varifold.pdf: 379650 bytes, checksum: 341cfa2d9d25e41789652de4c99c22fe (MD5) %0 Report %D 2013 %T Ambrosio-Tortorelli approximation of cohesive fracture models in linearized elasticity %A Matteo Focardi %A Flaviana Iurlano %K Functions of bounded deformation %X We provide an approximation result in the sense of $\Gamma$-convergence for cohesive fracture energies of the form \[ \int_\Omega \mathscr{Q}_1(e(u))\,dx+a\,\mathcal{H}^{n-1}(J_u)+b\,\int_{J_u}\mathscr{Q}_0^{1/2}([u]\odot\nu_u)\,d\mathcal{H}^{n-1}, \] where $\Omega\subset{\mathbb R}^n$ is a bounded open set with Lipschitz boundary, $\mathscr{Q}_0$ and $\mathscr{Q}_1$ are coercive quadratic forms on ${\mathbb M}^{n\times n}_{sym}$, $a,\,b$ are positive constants, and $u$ runs in the space of fields $SBD^2(\Omega)$ , i.e., it's a special field with bounded deformation such that its symmetric gradient $e(u)$ is square integrable, and its jump set $J_u$ has finite $(n-1)$-Hausdorff measure in ${\mathbb R}^n$. The approximation is performed by means of Ambrosio-Tortorelli type elliptic regularizations, the prototype example being \[ \int_\Omega\Big(v|e(u)|^2+\frac{(1-v)^2}{\varepsilon}+{\gamma\,\varepsilon}|\nabla v|^2\Big)\,dx, \] where $(u,v)\in H^1(\Omega,{\mathbb R}^n){\times} H^1(\Omega)$, $\varepsilon\leq v\leq 1$ and $\gamma>0$. %I SISSA %G en %U http://hdl.handle.net/1963/6615 %1 6573 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Flaviana Iurlano (iurlano@sissa.it) on 2013-05-13T11:26:04Z No. of bitstreams: 1 coesivo17_preprint_SISSA.pdf: 482275 bytes, checksum: 890efd398f9ff18a36d5b18fc90f8107 (MD5) %0 Journal Article %D 2013 %T Analytical validation of a continuum model for epitaxial growth with elasticity on vicinal surfaces %A Gianni Dal Maso %A Irene Fonseca %A Giovanni Leoni %K singular nonlinear parabolic equations, Hilbert transform, thin films %X In this paper it is shown existence of weak solutions of a variational inequality derived from the continuum model introduced by Xiang [7, formula (3.62)] (see also the work of Xiang and E [8] and Xu and Xiang [9]) to describe the self-organization of terraces and steps driven by misfit elasticity between a film and a substrate in heteroepitaxial growth. This model is obtained as a continuum limit of discrete theories of Duport, Politi, and Villain [3] and Tersoff, Phang, Zhang, and Lagally[6]. %I Springer %G en %U http://hdl.handle.net/1963/7245 %1 7284 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Gianni Dal Maso (dalmaso@sissa.it) on 2014-01-15T08:47:14Z No. of bitstreams: 1 DM-Fon-Leo.pdf: 409459 bytes, checksum: 07429e936667a481a2c093217e585e84 (MD5) %R 10.1007/s00205-014-0730-4 %0 Thesis %D 2013 %T An Approximation Result for Generalised Functions of Bounded Deformation and Applications to Damage Problems %A Flaviana Iurlano %K Functions of bounded deformation %I SISSA %G en %1 7203 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Flaviana Iurlano (iurlano@sissa.it) on 2013-10-23T12:46:25Z No. of bitstreams: 1 Iurlano - PhD Thesis.pdf: 1234569 bytes, checksum: e031f9fd97f6a1662f96f1caf2bc564e (MD5) %0 Report %D 2013 %T On the area of the graph of a piecewise smooth map from the plane to the plane with a curve discontinuity %A Giovanni Bellettini %A Lucia Tealdi %A Maurizio Paolini %K Area functional %X In this paper we provide an estimate from above for the value of the relaxed area functional for a map defined on a bounded domain of the plane with values in the plane and discontinuous on a regular simple curve with two endpoints. We show that, under suitable assumptions, the relaxed area does not exceed the area of the regular part of the map, with the addition of a singular term measuring the area of a disk type solution of the Plateau's problem spanning the two traces of the map on the jump. The result is valid also when the area minimizing surface has self intersections. A key element in our argument is to show the existence of what we call a semicartesian parametrization of this surface, namely a conformal parametrization defined on a suitable parameter space, which is the identity in the first component. To prove our result, various tools of parametric minimal surface theory are used, as well as some result from Morse theory. %G en %1 7257 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Lucia Tealdi (ltealdi@sissa.it) on 2013-11-29T13:51:49Z No. of bitstreams: 1 bellettini_paolini_tealdi_SISSAprprint.pdf: 705021 bytes, checksum: 98a550aeb5925de05f6b419569ccd283 (MD5) %0 Journal Article %D 2013 %T Asymptotics of the first Laplace eigenvalue with Dirichlet regions of prescribed length %A Paolo Tilli %A Davide Zucco %X We consider the problem of maximizing the first eigenvalue of the $p$-Laplacian (possibly with nonconstant coefficients) over a fixed domain $\Omega$, with Dirichlet conditions along $\partial\Omega$ and along a supplementary set $\Sigma$, which is the unknown of the optimization problem. The set $\Sigma$, which plays the role of a supplementary stiffening rib for a membrane $\Omega$, is a compact connected set (e.g., a curve or a connected system of curves) that can be placed anywhere in $\overline{\Omega}$ and is subject to the constraint of an upper bound $L$ to its total length (one-dimensional Hausdorff measure). This upper bound prevents $\Sigma$ from spreading throughout $\Omega$ and makes the problem well-posed. We investigate the behavior of optimal sets $\Sigma_L$ as $L\to\infty$ via $\Gamma$-convergence, and we explicitly construct certain asymptotically optimal configurations. We also study the behavior as $p\to\infty$ with $L$ fixed, finding connections with maximum-distance problems related to the principal frequency of the $\infty$-Laplacian. %I Society for Industrial and Applied Mathematics %G en %U http://urania.sissa.it/xmlui/handle/1963/35141 %1 35379 %2 Physics %4 1 %# MAT/05 %$ Approved for entry into archive by Maria Pia Calandra (calapia@sissa.it) on 2015-12-09T16:12:39Z (GMT) No. of bitstreams: 0 %R 10.1137/130916825 %0 Report %D 2013 %T Attainment results for nematic elastomers %A Virginia Agostiniani %A Gianni Dal Maso %A Antonio DeSimone %X We consider a class of non-quasiconvex frame indifferent energy densities which includes Ogden-type energy densities for nematic elastomers. For the corresponding geometrically linear problem we provide an explicit minimizer of the energy functional satisfying a nontrivial boundary condition. Other attainment results, both for the nonlinear and the linearized model, are obtained by using the theory of convex integration introduced by Mueller and Sverak in the context of crystalline solids. %I SISSA %G en %U http://hdl.handle.net/1963/7174 %1 7201 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Gianni Dal Maso (dalmaso@sissa.it) on 2013-10-22T14:32:26Z No. of bitstreams: 1 Ago-DM-DeS-13-sissa.pdf: 394672 bytes, checksum: d02690a6c7f206310d28d253ce53d0d3 (MD5) %0 Report %D 2013 %T Benchmarking the Immersed Finite Element Method for Fluid-Structure Interaction Problems %A Luca Heltai %A Francesco Costanzo %A Saswati Roy %X We present an implementation of a fully variational formulation of an immersed methods for fluid-structure interaction problems based on the finite element method. While typical implementation of immersed methods are characterized by the use of approximate Dirac delta distributions, fully variational formulations of the method do not require the use of said distributions. In our implementation the immersed solid is general in the sense that it is not required to have the same mass density and the same viscous response as the surrounding fluid. We assume that the immersed solid can be either viscoelastic of differential type or hyperelastic. Here we focus on the validation of the method via various benchmarks for fluid-structure interaction numerical schemes. This is the first time that the interaction of purely elastic compressible solids and an incompressible fluid is approached via an immersed method allowing a direct comparison with established benchmarks. %I SISSA %G en %U http://hdl.handle.net/1963/6972 %1 6957 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Luca Heltai (heltai@sissa.it) on 2013-06-17T09:29:07Z No. of bitstreams: 1 rhc_feibm_validation.pdf: 6746546 bytes, checksum: 51822772fafdd2e384572effb63a3fa2 (MD5) %0 Thesis %D 2013 %T Biregular and Birational Geometry of Algebraic Varieties %A Alex Massarenti %K Moduli spaces of curves, automorphisms, Hassett's moduli spaces, varieties of sums of powers %X Every area of mathematics is characterized by a guiding problem. In algebraic geometry such problem is the classification of algebraic varieties. In its strongest form it means to classify varieties up to biregular morphisms. However, birationally equivalent varieties share many interesting properties. Therefore for any birational equivalence class it is natural to work out a variety, which is the simplest in a suitable sense, and then study these varieties. This is the aim of birational geometry. In the first part of this thesis we deal with the biregular geometry of moduli spaces of curves, and in particular with their biregular automorphisms. However, in doing this we will consider some aspects of their birational geometry. The second part is devoted to the birational geometry of varieties of sums of powers and to some related problems which will lead us to computational geometry and geometric complexity theory. %I SISSA %G en %1 6962 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Alex Massarenti (massaren@sissa.it) on 2013-06-25T07:25:44Z No. of bitstreams: 1 AM_Thesis.pdf: 1175018 bytes, checksum: 8259bac19804f82ad17c11cd27d11c4a (MD5) %0 Journal Article %J Communications in Mathematical Physics 323, nr. 2 (2013) 663-711 %D 2013 %T Classical W-algebras and generalized Drinfeld-Sokolov bi-Hamiltonian systems within the theory of Poisson vertex algebras %A Alberto De Sole %A Victor G. Kac %A Daniele Valeri %X We provide a description of the Drinfeld-Sokolov Hamiltonian reduction for the construction of classical W-algebras within the framework of Poisson vertex algebras. In this context, the gauge group action on the phase space is translated in terms of (the exponential of) a Lie conformal algebra action on the space of functions. Following the ideas of Drinfeld and Sokolov, we then establish under certain sufficient conditions the applicability of the Lenard-Magri scheme of integrability and the existence of the corresponding integrable hierarchy of bi-Hamiltonian equations. %B Communications in Mathematical Physics 323, nr. 2 (2013) 663-711 %I Springer %G en %U http://hdl.handle.net/1963/6978 %1 6966 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Daniele Valeri (dvaleri@sissa.it) on 2013-07-13T15:24:57Z No. of bitstreams: 1 1207.6286v3.pdf: 588052 bytes, checksum: a5630eb1399cba992d56be98f25cdc9c (MD5) %R 10.1007/s00220-013-1785-z %0 Journal Article %J Comptes Rendus Mathematique. Volume 351, Issue 15-16, August 2013, Pages 593-598 %D 2013 %T A combination between the reduced basis method and the ANOVA expansion: On the computation of sensitivity indices %A Denis Devaud %A Andrea Manzoni %A Gianluigi Rozza %K Partial differential equations %XWe consider a method to efficiently evaluate in a real-time context an output based on the numerical solution of a partial differential equation depending on a large number of parameters. We state a result allowing to improve the computational performance of a three-step RB-ANOVA-RB method. This is a combination of the reduced basis (RB) method and the analysis of variations (ANOVA) expansion, aiming at compressing the parameter space without affecting the accuracy of the output. The idea of this method is to compute a first (coarse) RB approximation of the output of interest involving all the parameter components, but with a large tolerance on the a posteriori error estimate; then, we evaluate the ANOVA expansion of the output and freeze the least important parameter components; finally, considering a restricted model involving just the retained parameter components, we compute a second (fine) RB approximation with a smaller tolerance on the a posteriori error estimate. The fine RB approximation entails lower computational costs than the coarse one, because of the reduction of parameter dimensionality. Our result provides a criterion to avoid the computation of those terms in the ANOVA expansion that are related to the interaction between parameters in the bilinear form, thus making the RB-ANOVA-RB procedure computationally more feasible.

%B Comptes Rendus Mathematique. Volume 351, Issue 15-16, August 2013, Pages 593-598 %I Elsevier %G en %U http://hdl.handle.net/1963/7389 %1 7434 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-06-19T08:56:09Z No. of bitstreams: 1 Devaud_Manzoni_Rozza_2013.pdf: 564002 bytes, checksum: 4c93e74468534915513e6805d440dee9 (MD5) %R 10.1016/j.crma.2013.07.023 %0 Journal Article %J Nature. Scientific Reports 3, Article number: 1251, Published : 13 February 2013 %D 2013 %T Common dynamical features of sensory adaptation in photoreceptors and olfactory sensory neurons. %A Giovanna Di Palo %A Giuseppe Facchetti %A Monica Mazzolini %A Anna Menini %A Vincent Torre %A Claudio Altafini %X Sensory systems adapt, i.e., they adjust their sensitivity to external stimuli according to the ambient level. In this paper we show that single cell electrophysiological responses of vertebrate olfactory receptors and of photoreceptors to different input protocols exhibit several common features related to adaptation, and that these features can be used to investigate the dynamical structure of the feedback regulation responsible for the adaptation. In particular, we point out that two different forms of adaptation can be observed, in response to steps and to pairs of pulses. These two forms of adaptation appear to be in a dynamical trade-off: the more adaptation to a step is close to perfect, the slower is the recovery in adaptation to pulse pairs and viceversa. Neither of the two forms is explained by the dynamical models currently used to describe adaptation, such as the integral feedback model. %B Nature. Scientific Reports 3, Article number: 1251, Published : 13 February 2013 %I SISSA %G en %1 6453 %2 Mathematics %4 1 %$ Submitted by Claudio Altafini (altafini@sissa.it) on 2013-02-27T14:00:21Z\nNo. of bitstreams: 0 %R 10.1038/srep01251 %0 Journal Article %J Journal of Geometric Analysis 23, nr.2 (2013), pages 812-854 %D 2013 %T Connected Sum Construction for σk-Yamabe Metrics %A Giovanni Catino %A Lorenzo Mazzieri %X In this paper we produce families of Riemannian metrics with positive constant $\sigma_k$-curvature equal to $2^{-k} {n \choose k}$ by performing the connected sum of two given compact {\em non degenerate} $n$--dimensional solutions $(M_1,g_1)$ and $(M_2,g_2)$ of the (positive) $\sigma_k$-Yamabe problem, provided $2 \leq 2k < n$. The problem is equivalent to solve a second order fully nonlinear elliptic equation. %B Journal of Geometric Analysis 23, nr.2 (2013), pages 812-854 %I Springer %G en %U http://hdl.handle.net/1963/6441 %1 6366 %2 Mathematics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-01-29T10:41:53Z No. of bitstreams: 1 0910.5353v2.pdf: 355177 bytes, checksum: 0fa7b4a369607d617c4c167617460165 (MD5) %R 10.1007/s12220-011-9265-1 %0 Journal Article %J International Journal of Non-Linear Mechanics 56, 142-147 (2013) %D 2013 %T Crawlers in viscous environments: linear vs nonlinear rheology %A Antonio DeSimone %A Federica Guarnieri %A Giovanni Noselli %A Amabile Tatone %X We study model self-propelled crawlers which derive their propulsive capabilities from the tangential resistance to motion offered by the environment. Two types of relationships between tangential forces and slip velocities are considered: a linear, Newtonian one and a nonlinear one of Bingham-type. Different behaviors result from the two different rheologies. These differences and their implications in terms of motility performance are discussed. Our aim is to develop new tools and insight for future studies of cell motility by crawling. %B International Journal of Non-Linear Mechanics 56, 142-147 (2013) %I Elsevier %G en %1 34590 %2 Mathematics %$ Submitted by gnoselli@sissa.it (gnoselli@sissa.it) on 2015-03-07T17:29:52Z No. of bitstreams: 1 viscous_crawlers.pdf: 887755 bytes, checksum: 6022e4160d2eced97b51326bf51e0827 (MD5) %R 10.1016/j.ijnonlinmec.2013.02.007 %0 Report %D 2013 %T On critical behaviour in systems of Hamiltonian partial differential equations %A Boris Dubrovin %A Tamara Grava %A Christian Klein %A Antonio Moro %XWe study the critical behaviour of solutions to weakly dispersive Hamiltonian systems considered as perturbations of elliptic and hyperbolic systems of hydrodynamic type with two components. We argue that near the critical point of gradient catastrophe of the dispersionless system, the solutions to a suitable initial value problem for the perturbed equations are approximately described by particular solutions to the Painlev\'e-I (P$_I$) equation or its fourth order analogue P$_I^2$. As concrete examples we discuss nonlinear Schr\"odinger equations in the semiclassical limit. A numerical study of these cases provides strong evidence in support of the conjecture.

%I SISSA %G en %1 7280 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Tamara Grava (grava@sissa.it) on 2014-01-14T18:10:19Z No. of bitstreams: 1 EHfinal_3.pdf: 7760169 bytes, checksum: 1e98e693fbceb1268a5acd269dd9b03e (MD5) %0 Report %D 2013 %T Currents and dislocations at the continuum scale %A Riccardo Scala %A Nicolas Van Goethem %K Cartesian maps, integer-valued currents, dislocations, finite elasticity, minimization %XA striking geometric property of elastic bodies with dislocations is their non-Riemannian nature in the sense that the deformation cannot be written as the gradient of a one-to-one immersion, and hence that no displacement field can properly be defined as model variable. In fact, the deformation curl equals to the density of dislocations which is a concentrated Radon measure in the dislocation lines. In this paper we consider a countable family of dislocations, discuss the mathematical properties of such constraint deformations and study a variational problem in finite-strain elasticity. It turns out that both the deformation and the dislocation lines may be modelled by means of the mathematical theory of currents. In particular, Cartesian maps allow one to consider deformations in L^p with 1\leq p<2, which are appropriate for dislocation-induced strain singularities. Moreover, integer-multiplicity currents are perfectly suited to describe either the static or the dynamics of families of dislocations which mutually interact, and possibly form complex structures such as clusters. Though the evolution of dislocations is not considered in this paper, it is the main motivation of our approach. As a matter of fact, this work describes a conservative ground state where dislocations are assumed to obey energy minimization principles, and over which any relevant effect resorting to thermodynamics outside equilibrium might be added in a subsequent step within the proposed mathematical formalism.

%I SISSA %G en %1 6963 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Nicolas Van Goethem (vangoeth@sissa.it) on 2013-06-27T10:31:13Z No. of bitstreams: 1 CDCS.pdf: 388107 bytes, checksum: 1a1a67c4c2d93c02b77032913fd33c4e (MD5) %0 Report %D 2013 %T The curvature: a variational approach %A Andrei Agrachev %A Davide Barilari %A Luca Rizzi %K Crurvature, subriemannian metric, optimal control problem %X The curvature discussed in this paper is a rather far going generalization of the Riemannian sectional curvature. We define it for a wide class of optimal control problems: a unified framework including geometric structures such as Riemannian, sub-Riemannian, Finsler and sub-Finsler structures; a special attention is paid to the sub-Riemannian (or Carnot-Caratheodory) metric spaces. Our construction of the curvature is direct and naive, and it is similar to the original approach of Riemann. Surprisingly, it works in a very general setting and, in particular, for all sub-Riemannian spaces. %I SISSA %G en %U http://hdl.handle.net/1963/7226 %1 7260 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-12-03T08:46:32Z No. of bitstreams: 1 1306.5318v3.pdf: 991021 bytes, checksum: f99fb9f1455fa70fbca476e8fd2571af (MD5) %0 Journal Article %J Journal of Mathematical Physics. Volume 54, Issue 1, 22 January 2013, Article number 013518 %D 2013 %T Curved noncommutative torus and Gauss--Bonnet %A Ludwik Dabrowski %A Andrzej Sitarz %K Geometry %X We study perturbations of the flat geometry of the noncommutative two-dimensional torus T^2_\theta (with irrational \theta). They are described by spectral triples (A_\theta, \H, D), with the Dirac operator D, which is a differential operator with coefficients in the commutant of the (smooth) algebra A_\theta of T_\theta. We show, up to the second order in perturbation, that the zeta-function at 0 vanishes and so the Gauss-Bonnet theorem holds. We also calculate first two terms of the perturbative expansion of the corresponding local scalar curvature. %B Journal of Mathematical Physics. Volume 54, Issue 1, 22 January 2013, Article number 013518 %I American Institute of Physics %G en %U http://hdl.handle.net/1963/7376 %1 7424 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-06-17T13:10:21Z No. of bitstreams: 1 1204.0420v1.pdf: 126064 bytes, checksum: ffa850e50f99585d61676b1d2398af2f (MD5) %R 10.1063/1.4776202 %0 Report %D 2013 %T The deal.II Library, Version 8.1 %A Wolfgang Bangerth %A Timo Heister %A Luca Heltai %A Guido Kanschat %A Martin Kronbichler %A Matthias Maier %A Bruno Turcksin %A Toby D. Young %X This paper provides an overview of the new features of the finite element library deal.II version 8.0. %I SISSA %G en %U http://hdl.handle.net/1963/7236 %1 7272 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Luca Heltai (heltai@sissa.it) on 2013-12-10T10:43:08Z No. of bitstreams: 1 1312.2266v1.pdf: 245445 bytes, checksum: e00fcd6d7d9ac6e2076208958b07eef3 (MD5) %0 Report %D 2013 %T Defect annihilation and proliferation in active nematics %A Luca Giomi %A Mark J. Bowick %A Xu Ma %A M. Cristina Marchetti %X Liquid crystals inevitably possess topological defect excitations generated\r\nthrough boundary conditions, applied fields or in quenches to the ordered\r\nphase. In equilibrium pairs of defects coarsen and annihilate as the uniform\r\nground state is approached. Here we show that defects in active liquid crystals\r\nexhibit profoundly different behavior, depending on the degree of activity and\r\nits contractile or extensile character. While contractile systems enhance the\r\nannihilation dynamics of passive systems, extensile systems act to drive\r\ndefects apart so that they swarm around in the manner of topologically\r\nwell-characterized self-propelled particles. We develop a simple analytical\r\nmodel for the defect dynamics which reproduces the key features of both the\r\nnumerical solutions and recent experiments on microtuble-kinesin assemblies. %I SISSA %G en %U http://hdl.handle.net/1963/6566 %1 6517 %2 Mathematics %4 2 %# FIS/02 FISICA TEORICA, MODELLI E METODI MATEMATICI %$ Submitted by Luca Giomi (lgiomi@sissa.it) on 2013-04-04T08:03:17Z\nNo. of bitstreams: 1\n1303.4720v1.pdf: 2660135 bytes, checksum: 5fdf2d289b9b42a28ae3d000faee65fb (MD5) %0 Report %D 2013 %T On deformations of multidimensional Poisson brackets of hydrodynamic type %A Matteo Casati %K Hamiltonian operator %X The theory of Poisson Vertex Algebras (PVAs) is a good framework to treat Hamiltonian partial differential equations. A PVA consist of a pair $(\mathcal{A},\{\cdot_{\lambda}\cdot\})$ of a differential algebra $\mathcal{A}$ and a bilinear operation called the $\lambda$-bracket. We extend the definition to the class of algebras $\mathcal{A}$ endowed with $d\geq 1$ commuting derivations. We call this structure a multidimensional PVA: it is a suitable setting to the study of deformations of the Poisson bracket of hydrodynamic type associated to the Euler's equation of motion of $d$-dimensional incompressible fluids. We prove that for $d=2$ all the first order deformations of such class of Poisson brackets are trivial. %I SISSA %G en %U http://hdl.handle.net/1963/7235 %1 7271 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Matteo Casati (mcasati@sissa.it) on 2013-12-09T15:48:14Z No. of bitstreams: 1 1312.1878v1.pdf: 416883 bytes, checksum: d561f4d57afd0607190ba24368e563ae (MD5) %] 1. Introduction 1.1 Poisson Vertex Algebras 1.2 Poisson brackets of hydrodynamic type and their deformations 2. Multidimensional Poisson Vertex Algebras 2.1 Formal map space 2.2 Poisson bivector and Poisson brackets 2.3 Poisson Vertex Algebras 2.4 Proof of Master formula 2.5 Cohomology of Poisson Vertex Algebras 3. Multidimensional Poisson brackets of hydrodynamic type 3.1 Deformation of Lie-Poisson bracket of hydrodynamic type 3.2 Proof of Theorem 5 4. Concluding remarks %0 Report %D 2013 %T A density result for GSBD and its application to the approximation of brittle fracture energies %A Flaviana Iurlano %K Generalized functions of bounded deformation %X We present an approximation result for functions \\r\\n$u:\\\\Omega\\\\to \\\\mathbb{R}^n$ belonging to the space $GSBD(\\\\Omega)\\\\cap L^2(\\\\Omega,\\\\Rn)$ with $e(u)$ square integrable and $\\\\mathcal{H}^{n-1}(J_u)$ finite. The \\r\\napproximating functions $u_k$ are piecewise continuous functions \\r\\nsuch that $u_k\\\\to u$ in $L^2(\\\\Omega,\\\\mathbb{R}^n)$, $e(u_k)\\\\to e(u)$ in $L^2(\\\\Omega,\\\\mathbb{M}^{n{\\\\times}n}_{sym})$, \\r\\n$\\\\mathcal{H}^{n-1}(J_{u_k}\\\\triangle J_u)\\\\to 0$, and\\r\\n$|u_k^\\\\pm-u^\\\\pm|\\\\wedge1\\\\to0$ in $L^1(\\\\Omega)$. As \\r\\nan application, we provide the extension to the vector-valued case of \\r\\nthe $\\\\Gamma$-convergence result in $SBV(\\\\Omega)$ proved by Ambrosio and Tortorelli. %I SISSA %G en %U http://hdl.handle.net/1963/6373 %1 6307 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Flaviana Iurlano (iurlano@sissa.it) on 2013-01-09T16:00:50Z\\nNo. of bitstreams: 1\\nIurlano 12-12.pdf: 541089 bytes, checksum: bc185f00d276b2c11ec58a1da036cea6 (MD5) %0 Thesis %D 2013 %T On the desingularization of Kahler orbifolds with constant scalar curvature %A Riccardo Lena %I SISSA %G en %1 7263 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Riccardo Lena (lena@sissa.it) on 2013-12-03T10:06:16Z No. of bitstreams: 1 Lena - On the desingularization of Kahler orbifolds with constant scalar curvature.pdf: 1229721 bytes, checksum: 6e1cc67d3ba8db21345b068a638d4bf4 (MD5) %0 Journal Article %J Classical and Quantum Gravity. Volume 30, Issue 1, 7 January 2013, Article number 015006 %D 2013 %T Dirac operator on spinors and diffeomorphisms %A Ludwik Dabrowski %A Giacomo Dossena %K gravity %X The issue of general covariance of spinors and related objects is reconsidered. Given an oriented manifold $M$, to each spin structure $\sigma$ and Riemannian metric $g$ there is associated a space $S_{\sigma, g}$ of spinor fields on $M$ and a Hilbert space $\HH_{\sigma, g}= L^2(S_{\sigma, g},\vol{M}{g})$ of $L^2$-spinors of $S_{\sigma, g}$. The group $\diff{M}$ of orientation-preserving diffeomorphisms of $M$ acts both on $g$ (by pullback) and on $[\sigma]$ (by a suitably defined pullback $f^*\sigma$). Any $f\in \diff{M}$ lifts in exactly two ways to a unitary operator $U$ from $\HH_{\sigma, g} $ to $\HH_{f^*\sigma,f^*g}$. The canonically defined Dirac operator is shown to be equivariant with respect to the action of $U$, so in particular its spectrum is invariant under the diffeomorphisms. %B Classical and Quantum Gravity. Volume 30, Issue 1, 7 January 2013, Article number 015006 %I IOP Publishing %G en %U http://hdl.handle.net/1963/7377 %1 7425 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-06-17T13:30:17Z No. of bitstreams: 1 1209.2021v1.pdf: 201918 bytes, checksum: fe811643c070348a7dd399672ddad6f4 (MD5) %R 10.1088/0264-9381/30/1/015006 %0 Report %D 2013 %T Dislocation dynamics in crystals: a macroscopic theory in a fractional Laplace setting %A Serena Dipierro %A Giampiero Palatucci %A Enrico Valdinoci %K nonlocal Allen-Cahn equation %X We consider an evolution equation arising in the Peierls-Nabarro model for crystal dislocation. We study the evolution of such dislocation function and show that, at a macroscopic scale, the dislocations have the tendency to concentrate at single points of the crystal, where the size of the slip coincides with the natural periodicity of the medium. These dislocation points evolve according to the external stress and an interior repulsive potential. %I SISSA %G en %U http://hdl.handle.net/1963/7124 %1 7124 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Giampiero Palatucci (palatucc@sissa.it) on 2013-09-23T12:18:14Z No. of bitstreams: 1 Dipierro-Palatucci-Valdinoci.pdf: 651692 bytes, checksum: 839508f3ff7cdc4417c33991ebf3a9f3 (MD5) %0 Journal Article %J PloS one. Volume 8, Issue 7, July 2013 : e68078 %D 2013 %T Early phase of plasticity-related gene regulation and SRF dependent transcription in the hippocampus %A Giovanni Iacono %A Claudio Altafini %A Vincent Torre %X Hippocampal organotypic cultures are a highly reliable in vitro model for studying neuroplasticity: in this paper, we analyze the early phase of the transcriptional response induced by a 20 µM gabazine treatment (GabT), a GABA-Ar antagonist, by using Affymetrix oligonucleotide microarray, RT-PCR based time-course and chromatin-immuno-precipitation. The transcriptome profiling revealed that the pool of genes up-regulated by GabT, besides being strongly related to the regulation of growth and synaptic transmission, is also endowed with neuro-protective and pro-survival properties. By using RT-PCR, we quantified a time-course of the transient expression for 33 of the highest up-regulated genes, with an average sampling rate of 10 minutes and covering the time interval [10:90] minutes. The cluster analysis of the time-course disclosed the existence of three different dynamical patterns, one of which proved, in a statistical analysis based on results from previous works, to be significantly related with SRF-dependent regulation (p-value<0.05). The chromatin immunoprecipitation (chip) assay confirmed the rich presence of working CArG boxes in the genes belonging to the latter dynamical pattern and therefore validated the statistical analysis. Furthermore, an in silico analysis of the promoters revealed the presence of additional conserved CArG boxes upstream of the genes Nr4a1 and Rgs2. The chip assay confirmed a significant SRF signal in the Nr4a1 CArG box but not in the Rgs2 CArG box. %B PloS one. Volume 8, Issue 7, July 2013 : e68078 %I Public Library of Science %G en %U http://hdl.handle.net/1963/7287 %1 7332 %2 Neuroscience %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-03-14T11:26:18Z No. of bitstreams: 1 journal.pone.0068078.pdf: 1188661 bytes, checksum: 29e83864b33fd1a072fe4ab4da6fcc17 (MD5) %R 10.1371/journal.pone.0068078 %0 Journal Article %J ESAIM Control. Optim. Calc. Var. 19 (2013) 167-189 %D 2013 %T Epitaxially strained elastic films: the case of anisotropic surface energies %A Marco Bonacini %X In the context of a variational model for the epitaxial growth of strained elastic films, we study the effects of the presence of anisotropic surface energies in the determination of equilibrium configurations. We show that the threshold effect that describes the stability of flat morphologies in the isotropic case remains valid for weak anisotropies, but is no longer present in the case of highly anisotropic surface energies, where we show that the flat configuration is always a local minimizer of the total energy. The main tool used to obtain these results is a minimality criterion based on the positivity of the second variation. %B ESAIM Control. Optim. Calc. Var. 19 (2013) 167-189 %I EDP Sciences %G en %U http://hdl.handle.net/1963/4268 %1 3999 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-26T15:17:45Z\\r\\nNo. of bitstreams: 1\\r\\nbonacini_31_M.pdf: 278252 bytes, checksum: ae2b293dfe841dc6e68fcdf2bea68578 (MD5) %R 10.1051/cocv/2012003 %0 Report %D 2013 %T Equilibrium measures for a class of potentials with discrete rotational symmetries %A Ferenc Balogh %A Dario Merzi %X In this note the logarithmic energy problem with external potential $|z|^{2n}+tz^d+\bar{t}\bar{z}^d$ is considered in the complex plane, where $n$ and $d$ are positive integers satisfying $d\leq 2n$. Exploiting the discrete rotational invariance of the potential, a simple symmetry reduction procedure is used to calculate the equilibrium measure for all admissible values of $n,d$ and $t$. It is shown that, for fixed $n$ and $d$, there is a critical value $|t|=t_{cr}$ such that the support of the equilibrium measure is simply connected for $|t|We classify nonabelian extensions of Lie algebroids in the holomorphic or algebraic category, and introduce and study a spectral sequence that one can attach to any such extension and generalizes the Hochschild-Serre spectral sequence associated to an ideal in a Lie algebra. We compute the differentials of the spectral sequence up to $d_2$

%G en %1 7293 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Ugo Bruzzo (bruzzo@sissa.it) on 2014-02-14T14:16:47Z No. of bitstreams: 1 nonabelian-9.pdf: 401046 bytes, checksum: 3ebfee7dd06925fea31100611bc7e2ca (MD5) %0 Journal Article %J Communications in Mathematical Physics. Volume 318, Issue 1, 2013, Pages 111-130 %D 2013 %T Noncommutative circle bundles and new Dirac operators %A Ludwik Dabrowski %A Andrzej Sitarz %K Quantum principal bundles %X We study spectral triples over noncommutative principal U(1) bundles. Basing on the classical situation and the abstract algebraic approach, we propose an operatorial definition for a connection and compatibility between the connection and the Dirac operator on the total space and on the base space of the bundle. We analyze in details the example of the noncommutative three-torus viewed as a U(1) bundle over the noncommutative two-torus and find all connections compatible with an admissible Dirac operator. Conversely, we find a family of new Dirac operators on the noncommutative tori, which arise from the base-space Dirac operator and a suitable connection. %B Communications in Mathematical Physics. Volume 318, Issue 1, 2013, Pages 111-130 %I Springer %G en %U http://hdl.handle.net/1963/7384 %1 7432 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-06-18T10:06:43Z No. of bitstreams: 1 1012.3055v2.pdf: 181206 bytes, checksum: be182e0f568384847efe0f656a70634b (MD5) %R 10.1007/s00220-012-1550-8 %0 Journal Article %J Geometry Partial Differential Equations – proceedings, CRM Series (15), 2013. %D 2013 %T The nonlinear multidomain model: a new formal asymptotic analysis. %A Stefano Amato %A Giovanni Bellettini %A Maurizio Paolini %K bidomain model, anisotropic mean curvature, star-shaped combination %X We study the asymptotic analysis of a singularly perturbed weakly parabolic system of m- equations of anisotropic reaction-diffusion type. Our main result formally shows that solutions to the system approximate a geometric motion of a hypersurface by anisotropic mean curvature. The anisotropy, supposed to be uniformly convex, is explicit and turns out to be the dual of the star-shaped combination of the m original anisotropies. %B Geometry Partial Differential Equations – proceedings, CRM Series (15), 2013. %@ 8876424724 %G en %1 7259 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Stefano Amato (samato@sissa.it) on 2013-11-29T15:38:34Z No. of bitstreams: 1 bidomain_gen.pdf: 320909 bytes, checksum: a47cfa6c6dec3318d5d75f8a6a4a425b (MD5) %0 Journal Article %J Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 24 (2013), no. 3: 437–450 %D 2013 %T A note on KAM theory for quasi-linear and fully nonlinear forced KdV %A Pietro Baldi %A Massimiliano Berti %A Riccardo Montalto %K KAM for PDEs %X We present the recent results in [3] concerning quasi-periodic solutions for quasi-linear and fully nonlinear forced perturbations of KdV equations. For Hamiltonian or reversible nonlinearities the solutions are linearly stable. The proofs are based on a combination of di erent ideas and techniques: (i) a Nash-Moser iterative scheme in Sobolev scales. (ii) A regularization procedure, which conjugates the linearized operator to a di erential operator with constant coe cients plus a bounded remainder. These transformations are obtained by changes of variables induced by di eomorphisms of the torus and pseudo-di erential operators. (iii) A reducibility KAM scheme, which completes the reduction to constant coe cients of the linearized operator, providing a sharp asymptotic expansion of the perturbed eigenvalues. %B Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 24 (2013), no. 3: 437–450 %I European Mathematical Society %G en %1 7268 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-12-09T08:16:04Z No. of bitstreams: 1 Baldi-Berti-Montalto-Lincei-Note-KAM-forced-KdV.pdf: 322654 bytes, checksum: ddae153eff7ad17e2be36cb3ba1af9bf (MD5) %R 10.4171/RLM/660 %0 Journal Article %D 2013 %T One-dimensional swimmers in viscous fluids: dynamics, controllability, and existence of optimal controls %A Gianni Dal Maso %A Antonio DeSimone %A Marco Morandotti %X In this paper we study a mathematical model of one-dimensional swimmers\r\nperforming a planar motion while fully immersed in a viscous fluid. The\r\nswimmers are assumed to be of small size, and all inertial effects are\r\nneglected. Hydrodynamic interactions are treated in a simplified way, using the\r\nlocal drag approximation of resistive force theory. We prove existence and\r\nuniqueness of the solution of the equations of motion driven by shape changes\r\nof the swimmer. Moreover, we prove a controllability result showing that given\r\nany pair of initial and final states, there exists a history of shape changes\r\nsuch that the resulting motion takes the swimmer from the initial to the final\r\nstate. We give a constructive proof, based on the composition of elementary\r\nmaneuvers (straightening and its inverse, rotation, translation), each of which\r\nrepresents the solution of an interesting motion planning problem. Finally, we\r\nprove the existence of solutions for the optimal control problem of finding,\r\namong the histories of shape changes taking the swimmer from an initial to a\r\nfinal state, the one of minimal energetic cost. %I SISSA %G en %U http://hdl.handle.net/1963/6511 %1 6460 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Antonio De Simone (desimone@sissa.it) on 2013-02-27T18:33:39Z\nNo. of bitstreams: 1\n1302.0901v1.pdf: 602592 bytes, checksum: 22ad16440e44a649c5ed620325227f64 (MD5) %0 Journal Article %D 2013 %T One-dimensional swimmers in viscous fluids: dynamics, controllability, and existence of optimal controls %A Gianni Dal Maso %A Antonio DeSimone %A Marco Morandotti %X In this paper we study a mathematical model of one-dimensional swimmers performing a planar motion while fully immersed in a viscous fluid. The swimmers are assumed to be of small size, and all inertial effects are neglected. Hydrodynamic interactions are treated in a simplified way, using the local drag approximation of resistive force theory. We prove existence and uniqueness of the solution of the equations of motion driven by shape changes of the swimmer. Moreover, we prove a controllability result showing that given any pair of initial and final states, there exists a history of shape changes such that the resulting motion takes the swimmer from the initial to the final state. We give a constructive proof, based on the composition of elementary maneuvers (straightening and its inverse, rotation, translation), each of which represents the solution of an interesting motion planning problem. Finally, we prove the existence of solutions for the optimal control problem of finding, among the histories of shape changes taking the swimmer from an initial to a final state, the one of minimal energetic cost. %I SISSA %G en %U http://hdl.handle.net/1963/6467 %1 6412 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Gianni Dal Maso (dalmaso@sissa.it) on 2013-02-11T12:13:39Z No. of bitstreams: 1 DM-DeS-Mor-12-v10 sissa.pdf: 606490 bytes, checksum: 45f448186465b198ec31beb54afb0edf (MD5) %0 Report %D 2013 %T A permanence theorem for local dynamical systems %A Alessandro Fonda %A Paolo Gidoni %K permanence %X We provide a necessary and sufficient condition for permanence related to a local dynamical system on a suitable topological space. We then present an illustrative application to a Lotka–Volterra predator–prey model with intraspecific competition. %B Version of the preprint of the 11.06.2013 ; DOI :10.1016/j.na.2014.10.011 %G en %U http://hdl.handle.net/1963/6973 %1 6958 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Paolo Gidoni (pgidoni@sissa.it) on 2013-06-18T09:16:31Z No. of bitstreams: 1 Fonda-Gidoni_1.3_preprint.pdf: 274082 bytes, checksum: 7940ded23ecfad16419160daaa61d199 (MD5) %0 Journal Article %D 2013 %T Quadratic cohomology %A Andrei Agrachev %X We study homological invariants of smooth families of real quadratic forms as\r\na step towards a \"Lagrange multipliers rule in the large\" that intends to\r\ndescribe topology of smooth vector functions in terms of scalar Lagrange\r\nfunctions. %I SISSA %G en %1 6456 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-02-27T15:16:17Z\nNo. of bitstreams: 1\n1301.2059v1.pdf: 236951 bytes, checksum: a481b8e5391a39e5e87402873e4023f7 (MD5) %0 Report %D 2013 %T On a quadratic functional for scalar conservation laws %A Stefano Bianchini %A Stefano Modena %X We prove a quadratic interaction estimate for approximate solutions to scalar conservation laws obtained by the wavefront tracking approximation or the Glimm scheme. This quadratic estimate has been used in the literature to prove the convergence rate of the Glimm scheme. The proof is based on the introduction of a quadratic functional Q(t), decreasing at every interaction, and such that its total variation in time is bounded. Di erently from other interaction potentials present in the literature, the form of this functional is the natural extension of the original Glimm functional, and coincides with it in the genuinely nonlinear case. %I SISSA %G en %U http://hdl.handle.net/1963/6981 %1 6972 %2 Mathematics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-07-15T15:49:05Z No. of bitstreams: 1 31M_Bianchini_Modena.pdf: 710996 bytes, checksum: 8dd1a009996ca60b6c2f1dc96bb46f43 (MD5) %0 Journal Article %J Journal of the European Mathematical Society %D 2013 %T Quasi-periodic solutions with Sobolev regularity of NLS on Td with a multiplicative potential %A Massimiliano Berti %A Philippe Bolle %X We prove the existence of quasi-periodic solutions for Schrödinger equations with a multiplicative potential on Td , d ≥ 1, finitely differentiable nonlinearities, and tangential frequencies constrained along a pre-assigned direction. The solutions have only Sobolev regularity both in time and space. If the nonlinearity and the potential are C∞ then the solutions are C∞. The proofs are based on an improved Nash-Moser iterative scheme, which assumes the weakest tame estimates for the inverse linearized operators ("Green functions") along scales of Sobolev spaces. The key off-diagonal decay estimates of the Green functions are proved via a new multiscale inductive analysis. The main novelty concerns the measure and "complexity" estimates. © European Mathematical Society 2013. %B Journal of the European Mathematical Society %V 15 %P 229-286 %G eng %R 10.4171/JEMS/361 %0 Journal Article %J Numerische Mathematik, 2013 %D 2013 %T Reduced basis approximation and a posteriori error estimation for Stokes flows in parametrized geometries: roles of the inf-sup stability constants %A Gianluigi Rozza %A Phuong Huynh %A Andrea Manzoni %K parametrized Stokes equations %X In this paper we review and we extend the reduced basis approximation and a posteriori error estimation for steady Stokes flows in a ffinely parametrized geometries, focusing on the role played by the Brezzi\\\'s and Babu ska\\\'s stability constants. The crucial ingredients of the methodology are a Galerkin projection onto a low-dimensional space of basis functions properly selected, an a ne parametric dependence enabling to perform competitive Off ine-Online splitting in the computational\\r\\nprocedure and a rigorous a posteriori error estimation on eld variables.\\r\\nThe combination of these three factors yields substantial computational savings which are at the basis of an e fficient model order reduction, ideally suited for real-time simulation and many-query contexts (e.g. optimization, control or parameter identi cation). In particular, in this work we focus on i) the stability of the reduced basis approximation based on the Brezzi\\\'s saddle point theory and the introduction of a supremizer operator on the pressure terms, ii) a rigorous a posteriori error estimation procedure for velocity and pressure elds based on the Babu ska\\\'s inf-sup constant (including residuals calculations), iii) the computation of a lower bound of the stability constant, and iv) di erent options for the reduced basis spaces construction. We present some illustrative results for both\\r\\ninterior and external steady Stokes flows in parametrized geometries representing two parametrized classical Poiseuille and Couette \\r\\nflows, a channel contraction and a simple flow control problem around a curved obstacle. %B Numerische Mathematik, 2013 %I Springer %G en %U http://hdl.handle.net/1963/6339 %1 6269 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Gianluigi Rozza (grozza@sissa.it) on 2012-12-13T17:19:05Z\\nNo. of bitstreams: 1\\nStokes_HMR10_SISSA_report.pdf: 4641267 bytes, checksum: 82a163163a62d0b9deef8d5d6590f8d7 (MD5) %0 Book Section %B CEMRACS 2013 - Modelling and simulation of complex systems: stochastic and deterministic approaches %D 2013 %T Reduced Basis Approximation for the Structural-Acoustic Design based on Energy Finite Element Analysis (RB-EFEA) %A Denis Devaud %A Gianluigi Rozza %B CEMRACS 2013 - Modelling and simulation of complex systems: stochastic and deterministic approaches %V 48 %P 98-115 %G eng %R http://dx.doi.org/10.1051/proc/201448004 %0 Journal Article %J SIAM Journal on Scientific Computing %D 2013 %T Reduced basis method for parametrized elliptic optimal control problems %A Negri, F. %A Rozza, G. %A Manzoni, A. %A Quarteroni, A. %X We propose a suitable model reduction paradigm-the certified reduced basis method (RB)-for the rapid and reliable solution of parametrized optimal control problems governed by partial differential equations. In particular, we develop the methodology for parametrized quadratic optimization problems with elliptic equations as a constraint and infinite-dimensional control variable. First, we recast the optimal control problem in the framework of saddle-point problems in order to take advantage of the already developed RB theory for Stokes-type problems. Then, the usual ingredients of the RB methodology are called into play: a Galerkin projection onto a low-dimensional space of basis functions properly selected by an adaptive procedure; an affine parametric dependence enabling one to perform competitive offline-online splitting in the computational procedure; and an efficient and rigorous a posteriori error estimate on the state, control, and adjoint variables as well as on the cost functional. Finally, we address some numerical tests that confirm our theoretical results and show the efficiency of the proposed technique. %B SIAM Journal on Scientific Computing %V 35 %P A2316–A2340 %G eng %R 10.1137/120894737 %0 Report %D 2013 %T A Reduced Computational and Geometrical Framework for Inverse Problems in Haemodynamics %A Toni Lassila %A Andrea Manzoni %A Alfio Quarteroni %A Gianluigi Rozza %I SISSA %G en %1 6571 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Gianluigi Rozza (grozza@sissa.it) on 2013-04-30T14:47:07Z No. of bitstreams: 1 LMQR_inverse_problems_Haemo.pdf: 2913600 bytes, checksum: 9bff594072e6c7b4a664bdade361a1a9 (MD5) %0 Report %D 2013 %T A reduced-order strategy for solving inverse Bayesian identification problems in physiological flows %A Toni Lassila %A Andrea Manzoni %A Alfio Quarteroni %A Gianluigi Rozza %I SISSA %G en %1 6555 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Gianluigi Rozza (grozza@sissa.it) on 2013-04-12T10:16:42Z\nNo. of bitstreams: 1\nHanoi_RQML_2012_REVISED.pdf: 1360222 bytes, checksum: 4cb9ffaaf9fd67e3eacf4d9c060d0940 (MD5) %0 Report %D 2013 %T Reduction Strategies for Shape Dependent Inverse Problems in Haemodynamics %A Toni Lassila %A Andrea Manzoni %A Gianluigi Rozza %I SISSA %G en %1 6554 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Gianluigi Rozza (grozza@sissa.it) on 2013-04-12T09:59:54Z\nNo. of bitstreams: 1\n03910397-1.pdf: 531448 bytes, checksum: 0ec611490748bed35d10f612e8296f27 (MD5) %0 Thesis %D 2013 %T Semistability and Decorated Bundles %A Andrea Pustetto %K Decorated sheaves, semistability, moduli space, Mehta-Ramanathan, maximal destabilizing subsheaf %X This thesis is devoted to the study of semistability condition of type t=(a,b,c,N) decorated bundles and sheaves in order to better understand and simplify it. We approach the problem in two different ways: on one side we “enclose” the above semistability condition between a stronger semistability condition (\epsilon-semistability) and a weaker one (k-semistability), on the other side we try, and succeed for the case of a = 2, to bound the length of weighted filtrations on which one checks the semistability condition. %I SISSA %G en %U http://hdl.handle.net/1963/7130 %1 7132 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Andrea Pustetto (apustett@sissa.it) on 2013-09-25T09:47:01Z No. of bitstreams: 1 Semistability and Decorated Bundles.pdf: 829003 bytes, checksum: 22aa7f058a1945c70a0e0d29b46829e3 (MD5) %0 Journal Article %D 2013 %T Softly Constrained Films %A Luca Giomi %X The shape of materials is often subject to a number of geometric constraints\r\nthat limit the size of the system or fix the structure of its boundary. In soft\r\nand biological materials, however, these constraints are not always hard, but\r\nare due to other physical mechanisms that affect the overall force balance. A\r\ncapillary film spanning a flexible piece of wire or a cell anchored to a\r\ncompliant substrate by mean of adhesive contacts are examples of these softly\r\nconstrained systems in the macroscopic and microscopic world. In this article I\r\nreview some of the important mathematical and physical developments that\r\ncontributed to our understanding of shape formation in softly constrained films\r\nand their recent application to the mechanics of adherent cells. %I SISSA %G en %U http://hdl.handle.net/1963/6563 %1 6518 %2 Mathematics %4 2 %# FIS/02 FISICA TEORICA, MODELLI E METODI MATEMATICI %$ Submitted by Luca Giomi (lgiomi@sissa.it) on 2013-04-04T08:04:08Z\nNo. of bitstreams: 1\n1304.1077v1.pdf: 4248769 bytes, checksum: c955d3de3233f3619d546d93dab34c63 (MD5) %0 Thesis %D 2013 %T Some models of crack growth in brittle materials %A Simone Racca %K Quasi-static crack evolution %I SISSA %G en %1 7205 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Simone Racca (sracca@sissa.it) on 2013-10-23T13:11:13Z No. of bitstreams: 1 Racca_PhDThesis.pdf: 1710871 bytes, checksum: ea174e98f8849253e71cdefa52c6c8b8 (MD5) %] Introduction Chapter 1. Preliminaries Chapter 2. A viscosity-driven crack evolution Chapter 3.A variational model for the quasi-static growth of fractional dimensional brittle fractures Chapter 4. A model for crack growth with branching and kinking Bibliography %0 Journal Article %D 2013 %T Some open problems %A Andrei Agrachev %K Geometry %X We discuss some challenging open problems in the geometric control theory and sub-Riemannian geometry. %I SISSA %G en %U http://hdl.handle.net/1963/7070 %1 7064 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-09-16T09:39:55Z No. of bitstreams: 1 1304.2590v2.pdf: 169033 bytes, checksum: 43fab332ae3bb82c336a19ab7013c373 (MD5) %0 Journal Article %J Discrete Contin. Dyn. Syst. Ser. S %D 2013 %T Some remarks on the viscous approximation of crack growth %A Giuliano Lazzaroni %A Rodica Toader %K Variational models %XWe describe an existence result for quasistatic evolutions of cracks in antiplane elasticity obtained in [16] by a vanishing viscosity approach, with free (but regular enough) crack path. We underline in particular the motivations for the choice of the class of admissible cracks and of the dissipation potential. Moreover, we extend the result to a model with applied forces depending on time.

%B Discrete Contin. Dyn. Syst. Ser. S %I SISSA %V 6 %G en %U http://hdl.handle.net/1963/4206 %1 3945 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-23T10:54:36Z No. of bitstreams: 1 Lazzaroni_Toader_24_M.pdf: 225564 bytes, checksum: 4c5000d79e83902639a8efb34ba9c0c8 (MD5) %& 131-146 %0 Thesis %D 2013 %T Some topics on Higgs bundles over projective varieties and their moduli spaces %A Alessio Lo Giudice %I SISSA %17131

%2Mathematics

%0 Thesis %D 2013 %T Some topics on Higgs bundles over projective varieties and their moduli spaces %A Alessio Lo Giudice %K Algebraic Geometry, Moduli spaces, Vector bundles %X In this thesis we study vector bundles on projective varieties and their moduli spaces. In Chapters 2, 3 and 4 we recall some basic notions as Higgs bundles, decorated bundles and generalized parabolic sheaves and introduce the problem we want to study. In chapter 5, we study Higgs bundles on nodal curves. After moving the problem on the normalization of the curve, starting from a Higgs bundle we obtain a generalized parabolic Higgs bundle. Using decorated bundles we are able to construct a projective moduli space which parametrizes equivalence classes of Higgs bundles on a nodal curve X. This chapter is an extract of a joint work with Andrea Pustetto Later on Chapter 6 is devoted to the study of holomorphic pairs (or twisted Higgs bundles) on elliptic curve. Holomorphic pairs were introduced by Nitsure and they are a natural generalization of the concept of Higgs bundles. In this Chapter we extend a result of E. Franco, O. Garc\'ia-Prada And P.E. Newstead valid for Higgs bundles to holomorphic pairs. Finally the last Chapter describes a joint work with Professor Ugo Bruzzo. We study Higgs bundles over varieties with nef tangent bundle. In particular generalizing a result of Nitsure we prove that if a Higgs bundle $(E,\phi)$ over the variety X with nef tangent remains semisatble when pulled-back to any smooth curve then it discrimiant vanishes. %I SISSA %G en %1 7134 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Alessio Lo Giudice (logiudic@sissa.it) on 2013-09-25T11:22:08Z No. of bitstreams: 1 Some topics on Higgs bundles over projective varieties and their moduli spaces .pdf: 666905 bytes, checksum: 58cf6bb5b212512b46c870b0d955a865 (MD5) %0 Report %D 2013 %T The splitting theorem in non-smooth context %A Nicola Gigli %X We prove that an infinitesimally Hilbertian $CD(0,N)$ space containing a line splits as the product of $R$ and an infinitesimally Hilbertian $CD(0,N −1)$ space. By ‘infinitesimally Hilbertian’ we mean that the Sobolev space $W^{1,2}(X,d,m)$, which in general is a Banach space, is an Hilbert space. When coupled with a curvature-dimension bound, this condition is known to be stable with respect to measured Gromov-Hausdorff convergence. %G en %U http://preprints.sissa.it/handle/1963/35306 %1 35613 %2 Mathematics %4 1 %# MAT/05 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2018-02-23T12:45:43Z No. of bitstreams: 1 Splittingmms-submitted.pdf: 826242 bytes, checksum: 0395e29f7f4d768880e012ef1a77073a (MD5) %0 Report %D 2013 %T Stability of equilibrium configurations for elastic films in two and three dimensions %A Marco Bonacini %K Epitaxially strained elastic films %X We establish a local minimality sufficiency criterion, based on the strict positivity of the second variation, in the context of a variational model for the epitaxial growth of elastic films. Our result holds also in the three-dimensional case and for a general class of nonlinear elastic energies. Applications to the study of the local minimality of flat morphologies are also shown. %I SISSA %G en %1 6997 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Marco Bonacini (mbonacin@sissa.it) on 2013-08-07T11:12:48Z No. of bitstreams: 1 films.pdf: 595689 bytes, checksum: 009553ee1f902e6e6984675ad0cf70b6 (MD5) %0 Journal Article %J IEEE Transactions on Automatic Control. Volume 58, Issue 1, 2013, Article number6228517, Pages 74-85 %D 2013 %T Stabilization of Stochastic Quantum Dynamics via Open and Closed Loop Control %A Claudio Altafini %A Francesco Ticozzi %A K. Nishio %X In this paper, we investigate parametrization-free solutions of the problem of quantum pure state preparation and subspace stabilization by means of Hamiltonian control, continuous measurement, and quantum feedback, in the presence of a Markovian environment. In particular, we show that whenever suitable dissipative effects are induced either by the unmonitored environment, or by non-Hermitian measurements, there is no need for feedback, as open-loop time-invariant control is sufficient to achieve stabilization of the target set in probability. Constructive necessary and sufficient conditions on the form of the control Hamiltonian can be provided in this case. When time-invariant control is not sufficient, state stabilization can be attained by the addition of filtering-based feedback control %B IEEE Transactions on Automatic Control. Volume 58, Issue 1, 2013, Article number6228517, Pages 74-85 %G en %U http://hdl.handle.net/1963/6503 %1 6448 %2 Mathematics %4 1 %$ Approved for entry into archive by Lucio Lubiana (lubiana@sissa.it) on 2013-02-27T15:06:12Z (GMT) No. of bitstreams: 0 %R 10.1109/TAC.2012.2206713 %0 Journal Article %J Engineering Analysis with Boundary Elements %D 2013 %T A stable and adaptive semi-Lagrangian potential model for unsteady and nonlinear ship-wave interactions %A Mola, Andrea %A Heltai, Luca %A Desimone, Antonio %B Engineering Analysis with Boundary Elements %V 128–143 %P 37 %G eng %0 Journal Article %J Engineering Analysis with Boundary Elements, 37(1):128 – 143, 2013. %D 2013 %T A stable and adaptive semi-Lagrangian potential model for unsteady and nonlinear ship-wave interactions %A Andrea Mola %A Luca Heltai %A Antonio DeSimone %K Unsteady ship-wave interaction %XWe present an innovative numerical discretization of the equations of inviscid potential flow for the simulation of three dimensional unsteady and nonlinear water waves generated by a ship hull advancing in water. The equations of motion are written in a semi-Lagrangian framework, and the resulting integro-diff erential equations are discretized in space via an adaptive iso-parametric collocation Boundary Element Method, and in time via adaptive implicit Backward Di erentiation Formulas (BDF) with variable step and variable order. When the velocity of the advancing ship hull is non-negligible, the semi-Lagrangian formulation (also known as Arbitrary Lagrangian Eulerian formulation, or ALE) of the free surface equations contains dominant transport terms which are stabilized with a Streamwise Upwind Petrov-Galerkin (SUPG) method. The SUPG stabilization allows automatic and robust adaptation of the spatial discretization with unstructured quadrilateral grids. Preliminary results are presented where we compare our numerical model with experimental results on the case of a Wigley hull advancing in calm water with fi xed sink and trim.

%B Engineering Analysis with Boundary Elements, 37(1):128 – 143, 2013. %I SISSA %G en %U http://hdl.handle.net/1963/5669 %1 5457 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-03-16T11:19:51Z\\nNo. of bitstreams: 1\\nMolaHeltaiDeSimone-2012-aa.pdf: 1981527 bytes, checksum: 8a82da009242da0cf884e2c7f04009a6 (MD5) %0 Report %D 2013 %T Stable regular critical points of the Mumford-Shah functional are local minimizers %A Marco Bonacini %A Massimiliano Morini %K Mumford-Shah functional %X In this paper it is shown that any regular critical point of the Mumford-Shah functional, with positive definite second variation, is an isolated local minimizer with respect to competitors which are sufficiently close in the L^1-topology. %I SISSA %G en %1 6992 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Marco Bonacini (mbonacin@sissa.it) on 2013-07-25T12:49:07Z No. of bitstreams: 1 bonmor.pdf: 602550 bytes, checksum: 45e935bdd017828bd56281b8e33a3d3a (MD5) %0 Journal Article %J SIAM Journal on Numerical Analysis %D 2013 %T Stochastic optimal robin boundary control problems of advection-dominated elliptic equations %A Chen, P. %A Quarteroni, A. %A Rozza, G. %X In this work we deal with a stochastic optimal Robin boundary control problem constrained by an advection-diffusion-reaction elliptic equation with advection-dominated term. We assume that the uncertainty comes from the advection field and consider a stochastic Robin boundary condition as control function. A stochastic saddle point system is formulated and proved to be equivalent to the first order optimality system for the optimal control problem, based on which we provide the existence and uniqueness of the optimal solution as well as some results on stochastic regularity with respect to the random variables. Stabilized finite element approximations in physical space and collocation approximations in stochastic space are applied to discretize the optimality system. A global error estimate in the product of physical space and stochastic space for the numerical approximation is derived. Illustrative numerical experiments are provided. %B SIAM Journal on Numerical Analysis %V 51 %P 2700–2722 %G eng %R 10.1137/120884158 %0 Thesis %D 2013 %T The structure and regularity of admissible BV solutions to hyperbolic conservation laws in one space dimension %A Lei Yu %X This thesis is devoted to the study of the qualitative properties of admissible BV solutions to the strictly hyperbolic conservation laws in one space dimension by using wave-front tracking approximation. This thesis consists of two parts: • SBV-like regularity of vanishing viscosity BV solutions to strict hyperbolic systems of conservation laws. • Global structure of admissible BV solutions to strict hyperbolic conservation laws. %I SISSA %G en %1 7210 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Lei Yu (yulei@sissa.it) on 2013-10-23T15:42:25Z No. of bitstreams: 1 Thesis_main.pdf: 960810 bytes, checksum: d3e2f04a4bb7cc2c30ba82507d536edc (MD5) %] Contents 0.1 HyperbolicConservationLaws. .......................... 1 0.2 SBV and SBV-like regularity ........................... 3 0.3 Global structure of BV solutions ......................... 6 0.4 Main notations ................................... 9 1 Preliminary results 11 1.1 BV and SBV functions............................... 11 1.2 Coarea formula for BV function.......................... 15 1.3 The singular conservation law........................... 16 1.3.1 The Riemann problem........................... 17 1.3.2 Front tracking algorithm.......................... 18 1.3.3 Uniform boundedness estimates on the speed of wave fronts . . . . . . 19 1.4 The Cauchy problem for systems ......................... 21 1.4.1 Solution of Riemann problem....................... 22 1.4.2 Construction of solution by wave-front tracking approximation . . . . 26 2 SBV-like regularity for strictly hyperbolic systems of conservation laws 33 2.1 Overview of the chapter .............................. 33 2.2 The scalar case ................................... 34 2.3 Notations and settings for general systems.................... 37 2.3.1 Preliminary notation............................ 37 2.3.2 Construction of solutions to the Riemann problem . . . . . . . . . . . 38 2.3.3 Cantor part of the derivative of characteristic for i-th waves . . . . . 39 2.4 Main SBV regularity argument .......................... 40 2.5 Review of wave-front tracking approximation for general system . . . . . . . . 41 2.5.1 Description of the wave-front tracking approximation . . . . . . . . . . 42 2.5.2 Jump part of i-th waves.......................... 43 2.6 Proof of Theorem2.4.1............................... 46 2.6.1 Decay estimate for positive waves..................... 46 2.6.2 Decay estimate for negative waves .................... 47 2.7 SBV regularity for the i-th component of the i-th eigenvalue . . . . . . . . . 54 i CONTENTS 3 Global structure of admissible BV solutions to the piecewise genuinely nonlinear system 57 3.1 Description of wave-front tracking approximation . . . . . . . . . . . . . . . . 62 3.2 Construction of subdiscontinuity curves ..................... 63 3.3 Proof of the main theorems ............................ 67 3.4 A counterexample on general strict hyperbolic systems . . . . . . . . . . . . . 71 4 Global structure of entropy solutions to general scalar conservation law 75 4.1 Overview ...................................... 75 4.2 Estimates on the level sets of the front tracking approximations . . . . . . . . 76 4.2.1 Bounds on the initial points of the boundary curves of level sets . . . 77 4.2.2 Bound estimates on the derivative of the boundary curves of level sets 77 4.3 Level sets in the exact solutions.......................... 78 4.4 Lagrangian representative for the entropy solution . . . . . . . . . . . . . . . 84 4.5 Pointwise structure................................. 88 %0 Report %D 2013 %T On Sudakov's type decomposition of transference plans with norm costs %A Stefano Bianchini %A Sara Daneri %I SISSA %G en %U http://hdl.handle.net/1963/7206 %1 7234 %2 Mathematics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-11-08T11:08:16Z No. of bitstreams: 1 Sudakov_160813 (1).pdf: 1030337 bytes, checksum: 121734a60b7c507acb1e0ca656676a37 (MD5) %0 Report %D 2013 %T Symplectic instanton bundles on P3 and 't Hooft instantons %A Ugo Bruzzo %A Dimitri Markushevich %A Alexander Tikhomirov %X We introduce the notion of tame symplectic instantons by excluding a kind of pathological monads and show that the locus $I^*_{n,r}$ of tame symplectic instantons is irreducible and has the expected dimension, equal to $4n(r+1)-r(2r+1)$. The proof is inherently based on a relation between the spaces $I^*_{n,r}$ and the moduli spaces of 't Hooft instantons. %I arXiv:1312.5554 [math.AG] %G en %U http://urania.sissa.it/xmlui/handle/1963/34486 %1 34675 %2 Mathematics %4 1 %# MAT/03 %$ Submitted by Ugo Bruzzo (bruzzo@sissa.it) on 2015-08-07T20:57:05Z No. of bitstreams: 1 Symplectic_instantons_II-rev-dec2014.pdf: 340035 bytes, checksum: 8d0a2dfeea126810645c06e8b6352903 (MD5) %0 Journal Article %D 2013 %T The \textttdeal.II} Library, Version 8.1 %A W. Bangerth %A T. Heister %A L. Heltai %A G. Kanschat %A M. Kronbichler %A M. Maier %A B. Turcksin %A T. D. Young %G eng %U http://arxiv.org/abs/1312.2266 %0 Thesis %D 2013 %T Topology of moduli spaces of framed sheaves %A Gharchia Abdellaoui %K Moduli spaces, framed sheaves, instantons %I SISSA %G en %U http://hdl.handle.net/1963/7152 %1 7158 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Gharchia Abdellaoui (abdellao@sissa.it) on 2013-10-14T11:07:43Z No. of bitstreams: 1 Thesis.pdf: 1727939 bytes, checksum: b93e3969bd19c6608598757b8e61e69c (MD5) %0 Thesis %D 2013 %T Topology of moduli spaces of framed sheaves %A Gharchia Abdellaoui %I SISSA %G en %1 7129 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Gharchia Abdellaoui (abdellao@sissa.it) on 2013-09-24T21:27:50Z No. of bitstreams: 1 Thesis.pdf: 1723413 bytes, checksum: 3dce2a30b43f26691a94a4de51700cfa (MD5) %0 Report %D 2013 %T On the tritronquée solutions of P$_I^2$ %A Tamara Grava %A Andrei Kapaev %A Christian Klein %XFor equation P$_I^2$, the second member in the P$_I$ hierarchy, we prove existence of various degenerate solutions depending on the complex parameter $t$ and evaluate the asymptotics in the complex $x$ plane for $|x|\to\infty$ and $t=o(x^{2/3})$. Using this result, we identify the most degenerate solutions $u^{(m)}(x,t)$, $\hat u^{(m)}(x,t)$, $m=0,\dots,6$, called {\em tritronqu\'ee}, describe the quasi-linear Stokes phenomenon and find the large $n$ asymptotics of the coefficients in a formal expansion of these solutions. We supplement our findings by a numerical study of the tritronqu\'ee solutions.

%I SISSA %G en %1 7282 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Tamara Grava (grava@sissa.it) on 2014-01-14T18:35:53Z No. of bitstreams: 1 tritronquee_coeff.pdf: 753719 bytes, checksum: 812d268b2abe25ccbcc69eb40ff75f1f (MD5) %0 Journal Article %J Communications on Pure and Applied Mathematics, Volume 66, Issue 3, March 2013, Pages 332-371 %D 2013 %T A variational Analysis of the Toda System on Compact Surfaces %A Andrea Malchiodi %A David Ruiz %X In this paper we consider the Toda system of equations on a compact surface. We will give existence results by using variational methods in a non coercive case. A key tool in our analysis is a new Moser-Trudinger type inequality under suitable conditions on the center of mass and the scale of concentration of the two components u_1, u_2. %B Communications on Pure and Applied Mathematics, Volume 66, Issue 3, March 2013, Pages 332-371 %I Wiley %G en %U http://hdl.handle.net/1963/6558 %1 6489 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Andrea Malchiodi (malchiod@sissa.it) on 2013-03-14T10:26:34Z No. of bitstreams: 1 1105.3701v2.pdf: 306787 bytes, checksum: f64fe03fd72ea85831e8f8ca25e9f99e (MD5) %R 10.1002/cpa.21433 %0 Journal Article %J SIAM Journal on Numerical Analysis %D 2013 %T A weighted reduced basis method for elliptic partial differential equations with random input data %A Chen, P. %A Quarteroni, A. %A Rozza, G. %X In this work we propose and analyze a weighted reduced basis method to solve elliptic partial differential equations (PDEs) with random input data. The PDEs are first transformed into a weighted parametric elliptic problem depending on a finite number of parameters. Distinctive importance of the solution at different values of the parameters is taken into account by assigning different weights to the samples in the greedy sampling procedure. A priori convergence analysis is carried out by constructive approximation of the exact solution with respect to the weighted parameters. Numerical examples are provided for the assessment of the advantages of the proposed method over the reduced basis method and the stochastic collocation method in both univariate and multivariate stochastic problems. %B SIAM Journal on Numerical Analysis %V 51 %P 3163–3185 %G eng %R 10.1137/130905253 %0 Journal Article %J SIAM J. Control Optim., 50 (2012) 559–582 %D 2012 %T On 2-step, corank 2 nilpotent sub-Riemannian metrics %A Davide Barilari %A Ugo Boscain %A Jean-Paul Gauthier %X In this paper we study the nilpotent 2-step, corank 2 sub-Riemannian metrics\\r\\nthat are nilpotent approximations of general sub-Riemannian metrics. We exhibit optimal syntheses for these problems. It turns out that in general the cut time is not equal to the first conjugate time but has a simple explicit expression. As a byproduct of this study we get some smoothness properties of the spherical Hausdorff measure in the case of a generic 6 dimensional, 2-step corank 2 sub-Riemannian metric. %B SIAM J. Control Optim., 50 (2012) 559–582 %I Society for Industrial and Applied Mathematics %G en %U http://hdl.handle.net/1963/6065 %1 5950 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-08-01T12:38:52Z\\nNo. of bitstreams: 1\\n1105.5766v2.pdf: 271835 bytes, checksum: 0836f63f262f14fbd4d44422b6c85686 (MD5) %R 10.1137/110835700 %0 Journal Article %J Discrete Contin. Dyn. Syst. 33, nr.7 (2012): 2777-2790 %D 2012 %T Asymptotics of the $s$-perimeter as $s\searrow 0$ %A Serena Dipierro %A Alessio Figalli %A Giampiero Palatucci %A Enrico Valdinoci %X We deal with the asymptotic behavior of the $s$-perimeter of a set $E$ inside a domain $\Omega$ as $s\searrow0$. We prove necessary and sufficient conditions for the existence of such limit, by also providing an explicit formulation in terms of the Lebesgue measure of $E$ and $\Omega$. Moreover, we construct examples of sets for which the limit does not exist. %B Discrete Contin. Dyn. Syst. 33, nr.7 (2012): 2777-2790 %I American Institute of Mathematical Sciences %G en %1 7317 %2 Mathematics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2014-03-11T15:55:21Z No. of bitstreams: 1 1204.0750v2.pdf: 216883 bytes, checksum: 3ee8d497a2c0f9a211ec5327e8aa6b9a (MD5) %R 10.3934/dcds.2013.33.2777 %0 Journal Article %J Geotechnique, Volume 62, Issue 12, December 2012, Pages 1081-1094 %D 2012 %T On the behaviour of flexible retaining walls under seismic actions %A Riccardo Conti %A G.S.P. Madabhushi %A Giulia M.B. Viggiani %K Centrifuge modelling %X This paper describes an experimental investigation of the behaviour of embedded retaining walls under seismic actions. Nine centrifuge tests were carried out on reduced-scale models of pairs of retaining walls in dry sand, either cantilevered or with one level of props near the top. The experimental data indicate that, for maximum accelerations that are smaller than the critical limit equilibrium value, the retaining walls experience significant permanent displacements under increasing structural loads, whereas for larger accelerations the walls rotate under constant internal forces. The critical acceleration at which the walls start to rotate increases with increasing maximum acceleration. No significant displacements are measured if the current earthquake is less severe than earthquakes previously experienced by the wall. The increase of critical acceleration is explained in terms of redistribution of earth pressures and progressive mobilisation of the passive strength in front of the wall. The experimental data for cantilevered retaining walls indicate that the permanent displacements of the wall can be reasonably predicted adopting a Newmark-type calculation with a critical acceleration that is a fraction of the limit equilibrium value. %B Geotechnique, Volume 62, Issue 12, December 2012, Pages 1081-1094 %I ICE Publishing %G en %U http://hdl.handle.net/1963/6933 %1 6912 %2 Mathematics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-05-30T10:11:44Z No. of bitstreams: 0 %R 10.1680/geot.11.P.029 %0 Journal Article %J Mathematical Modelling and Numerical Analysis, in press, 2012-13 %D 2012 %T Boundary control and shape optimization for the robust design of bypass anastomoses under uncertainty %A Toni Lassila %A Andrea Manzoni %A Alfio Quarteroni %A Gianluigi Rozza %K shape optimization %X We review the optimal design of an arterial bypass graft following either a (i) boundary optimal control approach, or a (ii) shape optimization formulation. The main focus is quantifying and treating the uncertainty in the residual flow when the hosting artery is not completely occluded,\\r\\nfor which the worst-case in terms of recirculation e ffects is inferred to correspond to a strong ori fice flow through near-complete occlusion. A worst-case optimal control approach is applied to the steady\\r\\nNavier-Stokes equations in 2D to identify an anastomosis angle and a cu ed shape that are robust with respect to a possible range of residual \\r\\nflows. We also consider a reduced order modelling framework\\r\\nbased on reduced basis methods in order to make the robust design problem computationally feasible. The results obtained in 2D are compared with simulations in a 3D geometry but without model\\r\\nreduction or the robust framework. %B Mathematical Modelling and Numerical Analysis, in press, 2012-13 %I Cambridge University Press %G en %U http://hdl.handle.net/1963/6337 %1 6267 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Gianluigi Rozza (grozza@sissa.it) on 2012-12-13T15:38:41Z\\nNo. of bitstreams: 1\\nLMQR_M2AN_Special_SISSAreport.pdf: 5702019 bytes, checksum: 037e51bde713582eff1ee9766b1b4559 (MD5) %0 Journal Article %J Journal of dynamical and control systems 18, nr. 1 (2012) 135-158 %D 2012 %T On a class of vector fields with discontinuity of divide-by-zero type and its applications %A Roberta Ghezzi %A Alexey O. Remizov %X We study phase portraits and singular points of vector fields of a special type, that is, vector fields whose components are fractions with a common denominator vanishing on a smooth regular hypersurface in the phase space. We assume also some additional conditions, which are fulfilled, for instance, if the vector field is divergence-free. This problem is motivated by a large number of applications. In this paper, we consider three of them in the framework of differential geometry: singularities of geodesic flows in various singular metrics on surfaces. %B Journal of dynamical and control systems 18, nr. 1 (2012) 135-158 %I Springer %G en %1 7038 %2 Mathematics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-08-14T09:32:26Z No. of bitstreams: 1 1007.0912v1.pdf: 311033 bytes, checksum: 66a06c5e2764120aa6d9ac971a82baab (MD5) %R 10.1007/s10883-012-9137-4 %0 Journal Article %J Theoretical and Mathematical Physics. Volume 172, Issue 1, July 2012, Pages 911-931 %D 2012 %T Classical double, R-operators, and negative flows of integrable hierarchies %A Boris Dubrovin %A Taras V. Skrypnyk %X Using the classical double G of a Lie algebra g equipped with the classical R-operator, we define two sets of functions commuting with respect to the initial Lie–Poisson bracket on g and its extensions. We consider examples of Lie algebras g with the “Adler–Kostant–Symes” R-operators and the two corresponding sets of mutually commuting functions in detail. Using the constructed commutative Hamiltonian flows on different extensions of g, we obtain zero-curvature equations with g-valued U–V pairs. The so-called negative flows of soliton hierarchies are among such equations. We illustrate the proposed approach with examples of two-dimensional Abelian and non-Abelian Toda field equations. %B Theoretical and Mathematical Physics. Volume 172, Issue 1, July 2012, Pages 911-931 %I SISSA %G en %U http://hdl.handle.net/1963/6468 %1 6413 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Approved for entry into archive by Lucio Lubiana (lubiana@sissa.it) on 2013-02-11T14:56:54Z (GMT) No. of bitstreams: 0 %R 10.1007/s11232-012-0086-6 %0 Journal Article %J Journal fur die Reine und Angewandte Mathematik, Issue 671, October 2012, Pages 131-198 %D 2012 %T A Codazzi-like equation and the singular set for C1 smooth surfaces in the Heisenberg group. %A Andrea Malchiodi %A Paul Yang %A Jih-Hsin Cheng %A JennFang Hwang %X In this paper, we study the structure of the singular set for a C 1 smooth surface in the 3-dimensional Heisenberg group ℍ 1. We discover a Codazzi-like equation for the p-area element along the characteristic curves on the surface. Information obtained from this ordinary differential equation helps us to analyze the local configuration of the singular set and the characteristic curves. In particular, we can estimate the size and obtain the regularity of the singular set. We understand the global structure of the singular set through a Hopf-type index theorem. We also justify the Codazzi-like equation by proving a fundamental theorem for local surfaces in ℍ 1 %B Journal fur die Reine und Angewandte Mathematik, Issue 671, October 2012, Pages 131-198 %I SISSA %G en %U http://hdl.handle.net/1963/6556 %1 6490 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Approved for entry into archive by Lucio Lubiana (lubiana@sissa.it) on 2013-03-25T14:33:32Z (GMT) No. of bitstreams: 0 %R 10.1515/CRELLE.2011.159 %0 Book Section %B Natural locomotion in fluids and on surfaces : swimming, flying, and sliding / editors Stephen Childress, Anette Hosoi, William W. Schultz, and Z. Jane Wang, editors, %D 2012 %T Computing optimal strokes for low reynolds number swimmers %A Antonio DeSimone %A Luca Heltai %A François Aouges %A Lefebvre-Lepot Aline %K Numerical analysis. %XWe discuss connections between low-Reynolds-number swimming and geometric control theory, and present a general algorithm for the numerical computation of energetically optimal strokes. As an illustration of our approach, we show computed motility maps and optimal strokes for two model swimmers.

%B Natural locomotion in fluids and on surfaces : swimming, flying, and sliding / editors Stephen Childress, Anette Hosoi, William W. Schultz, and Z. Jane Wang, editors, %I Springer %@ 9781461439967 %G en %U http://hdl.handle.net/1963/6445 %1 6381 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Luca Heltai (heltai@sissa.it) on 2013-02-01T17:33:50Z\\nNo. of bitstreams: 0 %R 10.1007/978-1-4614-3997-4_13 %0 Journal Article %J Journal of Differential Equations 252 (2012) 35-55 %D 2012 %T Convergence of equilibria of thin elastic plates under physical growth conditions for the energy density %A Maria Giovanna Mora %A Lucia Scardia %X The asymptotic behaviour of the equilibrium configurations of a thin elastic plate is studied, as the thickness h of the plate goes to zero... %B Journal of Differential Equations 252 (2012) 35-55 %I Elsevier %G en_US %U http://hdl.handle.net/1963/3466 %1 872 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-01-27T17:20:35Z\\r\\nNo. of bitstreams: 1\\r\\nMor-Sca-09.pdf: 254787 bytes, checksum: 8051c8d87a7f4428cbaf9d8705b25266 (MD5) %R 10.1016/j.jde.2011.09.009 %0 Journal Article %D 2012 %T Convergence of equilibria of thin elastic plates under physical growth conditions for the energy density %A Maria Giovanna Mora %A Lucia Scardia %X The asymptotic behaviour of the equilibrium configurations of a thin elastic plate is studied, as the thickness $h$ of the plate goes to zero. More precisely, it is shown that critical points of the nonlinear elastic functional $\mathcal E^h$, whose energies (per unit thickness) are bounded by $Ch^4$, converge to critical points of the $\Gamma$-limit of $h^{-4}\mathcal E^h$. This is proved under the physical assumption that the energy density $W(F)$ blows up as $\det F\to0$. %I Elsevier %G en %1 7112 %2 Mathematics %4 -1 %$ Submitted by Francesca Arici (farici@sissa.it) on 2013-09-18T08:46:46Z No. of bitstreams: 1 0901.4041v1.pdf: 233717 bytes, checksum: 3fc33c8ee52cddb0adf0a197c87d0ce8 (MD5) %R 10.1016/j.jde.2011.09.009 %0 Journal Article %J Discrete and Computational Geometry, Volume 48, Issue 4, December 2012, Pages 1025-1047 %D 2012 %T Convex pencils of real quadratic forms %A Antonio Lerario %X We study the topology of the set X of the solutions of a system of two quadratic inequalities in the real projective space RP^n (e.g. X is the intersection of two real quadrics). We give explicit formulae for its Betti numbers and for those of its double cover in the sphere S^n; we also give similar formulae for level sets of homogeneous quadratic maps to the plane. We discuss some applications of these results, especially in classical convexity theory. We prove the sharp bound b(X)\leq 2n for the total Betti number of X; we show that for odd n this bound is attained only by a singular X. In the nondegenerate case we also prove the bound on each specific Betti number b_k(X)\leq 2(k+2). %B Discrete and Computational Geometry, Volume 48, Issue 4, December 2012, Pages 1025-1047 %I Springer %G en %U http://hdl.handle.net/1963/7099 %1 7097 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-09-17T11:33:51Z No. of bitstreams: 1 1106.4678v3.pdf: 250496 bytes, checksum: 3ad88e26b8325e50857d0d9f9aabd6ad (MD5) %R 10.1007/s00454-012-9460-2 %0 Journal Article %J The European Physical Journal E, Volume 35, Issue 9, September 2012, Article number85 %D 2012 %T Crawling motility through the analysis of model locomotors: two case studies %A Antonio DeSimone %A Amabile Tatone %X We study model locomotors on a substrate, which derive their propulsive capabilities from the tangential (viscous or frictional) resistance offered by the substrate. Our aim is to develop new tools and insight for future studies of cellular motility by crawling and of collective bacterial motion. The purely viscous case (worm) is relevant for cellular motility by crawling of individual cells. We re-examine some recent results on snail locomotion in order to assess the role of finely regulated adhesion mechanisms in crawling motility. Our main conclusion is that such regulation, although well documented in several biological systems, is not indispensable to accomplish locomotion driven by internal deformations, provided that the crawler may execute sufficiently large body deformations. Thus, there is no snail theorem. Namely, the crawling analog of the scallop theorem of low Reynolds number hydrodynamics does not hold for snail-like crawlers. The frictional case is obtained by assuming that the viscous coefficient governing tangential resistance forces, which act parallel and in the direction opposite to the velocity of the point to which they are applied, depends on the normal force acting at that point. We combine these surface interactions with inertial effects in order to investigate the mechanisms governing the motility of a bristle-robot. This model locomotor is easily manufactured and has been proposed as an effective tool to replicate and study collective bacterial motility. %B The European Physical Journal E, Volume 35, Issue 9, September 2012, Article number85 %I Springer %G en %U http://hdl.handle.net/1963/7017 %1 7014 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-08-12T11:01:46Z No. of bitstreams: 0 %R 10.1140/epje/i2012-12085-x %0 Journal Article %J Russian Journal of Mathematical Physics. Volume 19, Issue 4, December 2012, Pages 449-460 %D 2012 %T On the critical behavior in nonlinear evolutionary PDEs with small viscocity %A Boris Dubrovin %A Maria Elaeva %X We address the problem of general dissipative regularization of the quasilinear transport equation. We argue that the local behavior of solutions to the regularized equation near the point of gradient catastrophe for the transport equation is described by the logarithmic derivative of the Pearcey function, a statement generalizing the result of A.M.Il\\\'in \\\\cite{ilin}. We provide some analytic arguments supporting such conjecture and test it numerically. %B Russian Journal of Mathematical Physics. Volume 19, Issue 4, December 2012, Pages 449-460 %I SISSA %G en %U http://hdl.handle.net/1963/6465 %1 6409 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Boris Dubrovin (dubrovin@sissa.it) on 2013-02-08T11:28:04Z\\nNo. of bitstreams: 1\\ndubrovin_elaeva.pdf: 8618184 bytes, checksum: 3c56d1922af7001581ca4ceb4c79cc3b (MD5) %R 10.1134/S106192081204005X %0 Journal Article %J Bioinformatics (Oxford, England). 2012 Jan; 28(1):76-83 %D 2012 %T Decompositions of large-scale biological systems based on dynamical properties %A Nicola Soranzo %A Fahimeh Ramezani %A Giovanni Iacono %A Claudio Altafini %X MOTIVATION: Given a large-scale biological network represented as an influence graph, in this article we investigate possible decompositions of the network aimed at highlighting specific dynamical properties.\\r\\nRESULTS: The first decomposition we study consists in finding a maximal directed acyclic subgraph of the network, which dynamically corresponds to searching for a maximal open-loop subsystem of the given system. Another dynamical property investigated is strong monotonicity. We propose two methods to deal with this property, both aimed at decomposing the system into strongly monotone subsystems, but with different structural characteristics: one method tends to produce a single large strongly monotone component, while the other typically generates a set of smaller disjoint strongly monotone subsystems.\\r\\nAVAILABILITY: Original heuristics for the methods investigated are described in the article. %B Bioinformatics (Oxford, England). 2012 Jan; 28(1):76-83 %I Oxford University Press %G en %U http://hdl.handle.net/1963/5226 %1 5049 %2 Physics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-01-16T15:13:23Z\\nNo. of bitstreams: 1\\nSoIaRaAl10.pdf: 185656 bytes, checksum: df5605453eb314d79ada4355b16ad3cd (MD5) %R 10.1093/bioinformatics/btr620 %0 Journal Article %J Phys. Rev. D 86 (2012) 124035 %D 2012 %T Deformed Lorentz symmetry and relative locality in a curved/expanding spacetime %A Giovanni Amelino-Camelia %A Antonino Marciano %A Marco Matassa %A Giacomo Rosati %K Doubly special relativity %X The interest of part of the quantum-gravity community in the possibility of\r\nPlanck-scale-deformed Lorentz symmetry is also fueled by the opportunities for testing the relevant scenarios with analyses, from a signal-propagation perspective, of observations of bursts of particles from cosmological distances. In this respect the fact that so far the implications of deformed Lorentz symmetry have been investigated only for flat (Minkowskian) spacetimes represents a very significant limitation, since for propagation over cosmological distances the curvature/expansion of spacetime is evidently tangible. We here provide a significant step toward filling this gap by exhibiting an explicit example of Planck-scale-deformed relativistic symmetries of a spacetime with constant rate of expansion (deSitterian). Technically we obtain the first ever example of a relativistic theory of worldlines of particles with 3 nontrivial relativistic invariants: a large speed scale (\"speed-of-light scale\"), a large distance scale (inverse of the \"expansion-rate scale\"), and a large momentum scale (\"Planck scale\"). We address some of the challenges that had obstructed success for previous attempts by exploiting the recent understanding of the connection between deformed Lorentz symmetry and relativity of spacetime locality. We also offer a preliminary analysis of the differences between the scenario we here propose and the most studied scenario for broken (rather than deformed) Lorentz symmetry in expanding spacetimes. %B Phys. Rev. D 86 (2012) 124035 %I American Physical Society %G en %1 6496 %2 Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-03-18T13:28:49Z\nNo. of bitstreams: 1\n1206.5315v1.pdf: 659285 bytes, checksum: 97c0ba29c809a911f9abb22708bae66c (MD5) %R 10.1103/PhysRevD.86.124035 %0 Journal Article %J Nucleic Acids Research, Volume 40, Issue 15, August 2012, Pages 7132-7149 %D 2012 %T Detection of transcriptional triggers in the dynamics of microbial growth: application to the respiratory-versatile bacterium Shewanella oneidensis %A Q Beg %A M Zampieri %A N Klitgord %A S Collins %A M Serres %A Daniel Segrè %A Claudio Altafini %X The capacity of microorganisms to respond to variable external conditions requires a coordination of environment-sensing mechanisms and decisionmaking regulatory circuits. Here, we seek to understand the interplay between these two processes by combining high-throughput measurement of time-dependent mRNA profiles with a novel computational approach that searches for key genetic triggers of transcriptional changes. Our approach helped us understand the regulatory strategies of a respiratorily versatile bacterium with promising bioenergy and bioremediation applications, Shewanella oneidensis, in minimal and rich media. By comparing expression profiles across these two conditions, we unveiled components of the transcriptional program that depend mainly on the growth phase. Conversely, by integrating our time-dependent data with a previously available large compendium of static perturbation responses, we identified transcriptional changes that cannot be explained solely by internal network dynamics, but are rather triggered by specific genes acting as key mediators of an environment-dependent response. These transcriptional triggers include known and novel regulators that respond to carbon, nitrogen and oxygen limitation. Our analysis suggests a sequence of physiological responses, including a coupling between nitrogen depletion and glycogen storage, partially recapitulated through dynamic flux balance analysis, and experimentally confirmed by metabolite measurements. Our approach is broadly applicable to other systems %B Nucleic Acids Research, Volume 40, Issue 15, August 2012, Pages 7132-7149 %I SISSA %G en %U http://hdl.handle.net/1963/6506 %1 6452 %2 Mathematics %4 1 %$ Approved for entry into archive by Lucio Lubiana (lubiana@sissa.it) on 2013-02-27T15:39:07Z (GMT) No. of bitstreams: 0 %R 10.1093/nar/gks467 %0 Journal Article %J Biophysical Journal. Volume 102, Issue 12, 20 June 2012, Pages 2677-2686 %D 2012 %T A dynamical feedback model for adaptation in the olfactory transduction pathway %A Giovanna De Palo %A Anna Boccaccio %A Andrew Miri %A Anna Menini %A Claudio Altafini %X Olfactory transduction exhibits two distinct types of adaptation, which we denote multipulse and step adaptation. In terms of measured transduction current, multipulse adaptation appears as a decrease in the amplitude of the second of two consecutive responses when the olfactory neuron is stimulated with two brief pulses. Step adaptation occurs in response to a sustained steplike stimulation and is characterized by a return to a steady-state current amplitude close to the prestimulus value, after a transient peak. In this article, we formulate a dynamical model of the olfactory transduction pathway, which includes the kinetics of the CNG channels, the concentration of Ca ions flowing through them, and the Ca-complexes responsible for the regulation. Based on this model, a common dynamical explanation for the two types of adaptation is suggested. We show that both forms of adaptation can be well described using different time constants for the kinetics of Ca ions (faster) and the kinetics of the feedback mechanisms (slower). The model is validated on experimental data collected in voltage-clamp conditions using different techniques and animal species. %B Biophysical Journal. Volume 102, Issue 12, 20 June 2012, Pages 2677-2686 %I Biophysical Society, Elsevier %G en %U http://hdl.handle.net/1963/7019 %1 7012 %2 Neuroscience %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-08-12T10:21:18Z No. of bitstreams: 1 1-s2.0-S0006349512005140-main.pdf: 607871 bytes, checksum: b57c678e05477bb1551bc379bc674a88 (MD5) %R 10.1016/j.bpj.2012.04.040 %0 Journal Article %J PloS one. 2012 ; 7(6):e38135 %D 2012 %T Dynamics of opinion forming in structurally balanced social networks %A Claudio Altafini %X A structurally balanced social network is a social community that splits into two antagonistic factions (typical example being a two-party political system). The process of opinion forming on such a community is most often highly predictable, with polarized opinions reflecting the bipartition of the network. The aim of this paper is to suggest a class of dynamical systems, called monotone systems, as natural models for the dynamics of opinion forming on structurally balanced social networks. The high predictability of the outcome of a decision process is explained in terms of the order-preserving character of the solutions of this class of dynamical systems. If we represent a social network as a signed graph in which individuals are the nodes and the signs of the edges represent friendly or hostile relationships, then the property of structural balance corresponds to the social community being splittable into two antagonistic factions, each containing only friends. %B PloS one. 2012 ; 7(6):e38135 %I PLoS %G en %U http://hdl.handle.net/1963/6051 %1 5942 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-08-01T07:37:37Z\\nNo. of bitstreams: 1\\njournal.pone.0038135.pdf: 460419 bytes, checksum: 94138ada3b8a6340ae8f7b5d3ec08c4e (MD5) %R 10.1371/journal.pone.0038135 %0 Journal Article %J Physical Review E - Statistical, Nonlinear, and Soft Matter Physics. Volume 86, Issue 3, 26 September 2012, Article number036116 %D 2012 %T Exploring the low-energy landscape of large-scale signed social networks %A Giuseppe Facchetti %A G Iacono %A Claudio Altafini %X Analogously to a spin glass, a large-scale signed social network is characterized by the presence of disorder, expressed in this context (and in the social network literature) by the concept of structural balance. If, as we have recently shown, the signed social networks currently available have a limited amount of true disorder (or frustration), it is also interesting to investigate how this frustration is organized, by exploring the landscape of near-optimal structural balance. What we obtain in this paper is that while one of the networks analyzed shows a unique valley of minima, and a funneled landscape that gradually and smoothly worsens as we move away from the optimum, another network shows instead several distinct valleys of optimal or near-optimal structural balance, separated by energy barriers determined by internally balanced subcommunities of users, a phenomenon similar to the replica-symmetry breaking of spin glasses. Multiple, essentially isoenergetic, arrangements of these communities are possible. Passing from one valley to another requires one to destroy the internal arrangement of these balanced subcommunities and then to reform it again. It is essentially this process of breaking the internal balance of the subcommunities which gives rise to the energy barriers. %B Physical Review E - Statistical, Nonlinear, and Soft Matter Physics. Volume 86, Issue 3, 26 September 2012, Article number036116 %I SISSA %G en %U http://hdl.handle.net/1963/6504 %1 6451 %2 Mathematics %4 1 %$ Approved for entry into archive by Lucio Lubiana (lubiana@sissa.it) on 2013-02-27T15:27:42Z (GMT) No. of bitstreams: 0 %R 10.1103/PhysRevE.86.036116 %0 Journal Article %J Analysis and Geometry in Metric Spaces, vol. 1 (2012), pages : 42-57 %D 2012 %T A formula for Popp\'s volume in sub-Riemannian geometry %A Luca Rizzi %A Davide Barilari %K subriemannian, volume, Popp, control %X For an equiregular sub-Riemannian manifold M, Popp\'s volume is a smooth\r\nvolume which is canonically associated with the sub-Riemannian structure, and\r\nit is a natural generalization of the Riemannian one. In this paper we prove a\r\ngeneral formula for Popp\'s volume, written in terms of a frame adapted to the\r\nsub-Riemannian distribution. As a first application of this result, we prove an\r\nexplicit formula for the canonical sub-Laplacian, namely the one associated\r\nwith Popp\'s volume. Finally, we discuss sub-Riemannian isometries, and we prove\r\nthat they preserve Popp\'s volume. We also show that, under some hypotheses on\r\nthe action of the isometry group of M, Popp\'s volume is essentially the unique\r\nvolume with such a property. %B Analysis and Geometry in Metric Spaces, vol. 1 (2012), pages : 42-57 %I SISSA %G en %U http://hdl.handle.net/1963/6501 %1 6446 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Luca Rizzi (lrizzi@sissa.it) on 2013-02-27T08:20:17Z\nNo. of bitstreams: 2\n1211.2325v2.pdf: 219748 bytes, checksum: 03a6289f4ee77387ad54e210dbb84b60 (MD5)\nagms-2012-0004.pdf: 1247984 bytes, checksum: 137bd44ed6f06bbbe02ed9dae33ab42a (MD5) %R 10.2478/agms-2012-0004 %0 Journal Article %J Communications in Mathematical Physics 311 (2012) 557-594 %D 2012 %T Frobenius manifold for the dispersionless Kadomtsev-Petviashvili equation %A Andrea Raimondo %X We consider a Frobenius structure associated with the dispersionless\\r\\nKadomtsev-Petviashvili equation. This is done, essentially, by applying a\\r\\ncontinuous analogue of the finite dimensional theory in the space of Schwartz\\r\\nfunctions on the line. The potential of the Frobenius manifold is found to be a\\r\\nlogarithmic potential with quadratic external field. Following the construction\\r\\nof the principal hierarchy, we construct a set of infinitely many commuting\\r\\nflows, which extends the classical dKP hierarchy. %B Communications in Mathematical Physics 311 (2012) 557-594 %I Springer %G en %U http://hdl.handle.net/1963/6040 %1 5931 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-07-31T12:51:57Z\\nNo. of bitstreams: 1\\n1008.2128v3.pdf: 349185 bytes, checksum: a5a3fa842d50f3d9450813e55218f093 (MD5) %R 10.1007/s00220-012-1470-7 %0 Report %D 2012 %T A Fully Coupled Immersed Finite Element Method for Fluid Structure Interaction via the Deal.II Library %A Luca Heltai %A Saswati Roy %A Francesco Costanzo %K Finite Element Method %K Immersed Boundary Method %K Immersed Finite Element Method %X We present the implementation of a solution scheme for fluid-structure\\r\\ninteraction problems via the finite element software library deal.II. The\\r\\nsolution scheme is an immersed finite element method in which two independent discretizations are used for the fluid and immersed deformable body. In this type of formulation the support of the equations of motion of the fluid is extended to cover the union of the solid and fluid domains. The equations of motion over the extended solution domain govern the flow of a fluid under the action of a body force field. This body force field informs the fluid of the presence of the immersed solid. The velocity field of the immersed solid is the restriction over the immersed domain of the velocity field in the extended equations of motion. The focus of this paper is to show how the determination of the motion of the immersed domain is carried out in practice. We show that our implementation is general, that is, it is not dependent on a specific choice of the finite element spaces over the immersed solid and the extended fluid domains. We present some preliminary results concerning the accuracy of the proposed method. %I SISSA %G en %U http://hdl.handle.net/1963/6255 %1 6172 %2 Mathematics %3 Functional Analysis and Applications %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Luca Heltai (heltai@sissa.it) on 2012-09-28T11:06:13Z\\nNo. of bitstreams: 1\\n1209.2811v1.pdf: 4766431 bytes, checksum: a46803f7f8daf3195359f65c9161b944 (MD5) %0 Journal Article %J Journal de Mathématiques Pures et Appliquées, Available online 12 September 2012 %D 2012 %T Gamma-convergence and H-convergence of linear elliptic operators %A Nadia Ansini %A Gianni Dal Maso %A Caterina Ida Zeppieri %K Linear elliptic operators %B Journal de Mathématiques Pures et Appliquées, Available online 12 September 2012 %I Elsevier %G en %U http://hdl.handle.net/1963/5878 %1 5746 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-05-30T13:02:32Z\\r\\nNo. of bitstreams: 1\\r\\n04M_2012_Ansini.pdf: 226441 bytes, checksum: 789582b685e552b522a3e8a896e091f8 (MD5) %R 10.1016/j.matpur.2012.09.004 %0 Journal Article %J Lett. Math. Phys. 101 (2012) 103-124 %D 2012 %T Gauge Theories on ALE Space and Super Liouville Correlation Functions %A Giulio Bonelli %A Kazunobu Maruyoshi %A Alessandro Tanzini %X We present a relation between N=2 quiver gauge theories on the ALE space O_{P^1}(-2) and correlators of N=1 super Liouville conformal field theory, providing checks in the case of punctured spheres and tori. We derive a blow-up formula for the full Nekrasov partition function and show that, up to a U(1) factor, the N=2^* instanton partition function is given by the product of the character of \\\\hat{SU}(2)_2 times the super Virasoro conformal block on the torus with one puncture. %B Lett. Math. Phys. 101 (2012) 103-124 %I SISSA %G en %U http://hdl.handle.net/1963/4305 %1 4068 %2 Physics %3 Elementary Particle Theory %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-28T07:00:50Z\\r\\nNo. of bitstreams: 1\\r\\n1107.4609v1.pdf: 256160 bytes, checksum: f34c8fc8ed919adff7b4d65312b81db1 (MD5) %R 10.1007/s11005-012-0553-x %0 Report %D 2012 %T Gauge Theories on ALE Space and Super Liouville Correlation Functions %A Giulio Bonelli %A Alessandro Tanzini %A Kazunobu Maruyoshi %X We present a relation between N=2 quiver gauge theories on the ALE space\r\nO_{P^1}(-2) and correlators of N=1 super Liouville conformal field theory,\r\nproviding checks in the case of punctured spheres and tori. We derive a blow-up\r\nformula for the full Nekrasov partition function and show that, up to a U(1)\r\nfactor, the N=2^* instanton partition function is given by the product of the\r\ncharacter of \\hat{SU}(2)_2 times the super Virasoro conformal block on the\r\ntorus with one puncture. Moreover, we match the perturbative gauge theory\r\ncontribution with super Liouville three-point functions. %I SISSA %G en %U http://hdl.handle.net/1963/6575 %1 6524 %2 Mathematics %4 -1 %$ Submitted by Alessandro Tanzini (tanzini@sissa.it) on 2013-04-04T10:02:37Z\nNo. of bitstreams: 1\n1107.4609v2.pdf: 276843 bytes, checksum: b8d179659f01feaf46e8f9ba65295cab (MD5) %0 Book Section %B Springer, Indam Series, Vol. 4, 2012 %D 2012 %T Generalized reduced basis methods and n-width estimates for the approximation of the solution manifold of parametric PDEs %A Toni Lassila %A Andrea Manzoni %A Alfio Quarteroni %A Gianluigi Rozza %K solution manifold %X The set of solutions of a parameter-dependent linear partial di fferential equation with smooth coe fficients typically forms a compact manifold in a Hilbert space. In this paper we review the generalized reduced basis method as a fast computational tool for the uniform approximation of the solution manifold. We focus on operators showing an affi ne parametric dependence, expressed as a linear combination of parameter-independent operators through some smooth, parameter-dependent scalar functions. In the case that the parameter-dependent operator has a dominant term in its affi ne expansion, one can prove the existence of exponentially convergent uniform approximation spaces for the entire solution manifold. These spaces can be constructed without any assumptions on the parametric regularity of the manifold \\r\\nonly spatial regularity of the solutions is required. The exponential convergence rate is then inherited by the generalized reduced basis method. We provide a numerical example related to parametrized elliptic\\r\\nequations con rming the predicted convergence rates. %B Springer, Indam Series, Vol. 4, 2012 %I Springer %G en %U http://hdl.handle.net/1963/6340 %1 6270 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Gianluigi Rozza (grozza@sissa.it) on 2012-12-13T17:47:45Z\\nNo. of bitstreams: 1\\nqlmr-bumi_FINAL_SISSAreport.pdf: 377397 bytes, checksum: ecaf5713afa6a6f68992f6331631aff4 (MD5) %0 Journal Article %J Russian Journal of Mathematical Physics. Volume 19, Issue 3, September 2012, Pages 273-298 %D 2012 %T On the genus two free energies for semisimple Frobenius manifolds %A Boris Dubrovin %A Si-Qi Liu %A Youjin Zhang %X We represent the genus two free energy of an arbitrary semisimple Frobenius\\r\\nmanifold as a sum of contributions associated with dual graphs of certain\\r\\nstable algebraic curves of genus two plus the so-called \\\"genus two G-function\\\".\\r\\nConjecturally the genus two G-function vanishes for a series of important\\r\\nexamples of Frobenius manifolds associated with simple singularities as well as\\r\\nfor ${\\\\bf P}^1$-orbifolds with positive Euler characteristics. We explain the\\r\\nreasons for such Conjecture and prove it in certain particular cases. %B Russian Journal of Mathematical Physics. Volume 19, Issue 3, September 2012, Pages 273-298 %I SISSA %G en %U http://hdl.handle.net/1963/6464 %1 6411 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Boris Dubrovin (dubrovin@sissa.it) on 2013-02-08T11:35:38Z\\nNo. of bitstreams: 1\\n1205.5990v1.pdf: 547320 bytes, checksum: 9c9d894fbe3241c632b6cab13379f9c9 (MD5) %R 10.1134/S1061920812030028 %0 Report %D 2012 %T Global structure of admissible BV solutions to piecewise genuinely nonlinear, strictly hyperbolic conservation laws in one space dimension %A Stefano Bianchini %A Lei Yu %K Hyperbolic conservation laws, Wave-front tracking, Global structure of solution. %X The paper gives an accurate description of the qualitative structure of an admissible BV solution to a strictly hyperbolic, piecewise genuinely nonlinear system of conservation laws. We prove that there are a countable set $\\\\Theta$ which contains all interaction points and a family of countably many Lipschitz curves $\\\\T$ such that outside $\\\\T\\\\cup \\\\Theta$ $u$ is continuous, and along the curves in $\\\\T$, u has left and right limit except for points in $\\\\Theta$. This extends the corresponding structural result in \\\\cite{BL,Liu1} for admissible solutions.\\r\\n\\r\\nThe proof is based on approximate wave-front tracking solutions and a proper selection of discontinuity curves in the approximate solutions, which converge to curves covering the discontinuities in the exact solution $u$. %I SISSA %G en %U http://hdl.handle.net/1963/6316 %1 6225 %2 Mathematics %3 Functional Analysis and Applications %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Lei Yu (yulei@sissa.it) on 2012-11-15T08:50:10Z\\nNo. of bitstreams: 1\\nglobal structure of solutions to PWGN hyperbolic conservation laws.pdf: 452219 bytes, checksum: 85bd51fc08fa53a087cee8aec2b9544a (MD5) %0 Journal Article %J Calculus of Variations and Partial Differential Equations. Volume 43, Issue 3-4, March 2012, Pages 355-388 %D 2012 %T On the Hausdorff volume in sub-Riemannian geometry %A Andrei Agrachev %A Davide Barilari %A Ugo Boscain %X For a regular sub-Riemannian manifold we study the Radon-Nikodym derivative\r\nof the spherical Hausdorff measure with respect to a smooth volume. We prove\r\nthat this is the volume of the unit ball in the nilpotent approximation and it\r\nis always a continuous function. We then prove that up to dimension 4 it is\r\nsmooth, while starting from dimension 5, in corank 1 case, it is C^3 (and C^4\r\non every smooth curve) but in general not C^5. These results answer to a\r\nquestion addressed by Montgomery about the relation between two intrinsic\r\nvolumes that can be defined in a sub-Riemannian manifold, namely the Popp and\r\nthe Hausdorff volume. If the nilpotent approximation depends on the point (that\r\nmay happen starting from dimension 5), then they are not proportional, in\r\ngeneral. %B Calculus of Variations and Partial Differential Equations. Volume 43, Issue 3-4, March 2012, Pages 355-388 %I SISSA %G en %U http://hdl.handle.net/1963/6454 %1 6399 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-02-05T13:55:36Z\r\nNo. of bitstreams: 1\r\n1005.0540v3.pdf: 352986 bytes, checksum: 7d3e71cad3c7ff917dc8769ba4cd96c5 (MD5) %R 10.1007/s00526-011-0414-y %0 Journal Article %J Nanoscale. 2012 Mar; 4(5):1734-41 %D 2012 %T Hybridization in nanostructured DNA monolayers probed by AFM: theory versus experiment %A Alessandro Bosco %A Fouzia Bano %A Pietro Parisse %A Loredana Casalis %A Antonio DeSimone %A Cristian Micheletti %X Nanografted monolayers (NAMs) of DNA show novel physico-chemical properties that make them ideally suited for advanced biosensing applications. In comparison with alternative solid-phase techniques for diagnostic DNA detection, NAMs have the advantage of combining a small size with a high homogeneity of the DNA surface coverage. These two properties favour the extreme miniaturization and ultrasensitivity in high-throughput biosensing devices. The systematic use of NAMs for quantitative DNA (and protein) detection has so far suffered from the lack of a control on key fabrication parameters, such as the ss- or ds-DNA surface coverage. Here we report on a combined experimental-computational study that allows us to estimate the surface density of the grafted DNA by analyzing the sample mechanical response, that is the DNA patch height vs. applied tip load curves. It is shown that the same analysis scheme can be used to detect the occurrence of hybridization with complementary strands in solution and estimate its efficiency. Thanks to these quantitative relationships it is possible to use a single AFM-based setup to: (i) fabricate a DNA NAM, (ii) control the DNA surface coverage, and (iii) characterize its level of hybridization helping the design of NAMs with pre-determined fabrication parameters. %B Nanoscale. 2012 Mar; 4(5):1734-41 %I Royal Society of Chemistry %G en %1 6998 %2 Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-08-08T07:48:55Z No. of bitstreams: 0 %R 10.1039/c2nr11662f %0 Journal Article %D 2012 %T An improved geometric inequality via vanishing moments, with applications to singular Liouville equations %A Andrea Malchiodi %A Daniele Bartolucci %I SISSA %G en %1 6485 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %0 Report %D 2012 %T Introduction to Riemannian and sub-Riemannian geometry %A Andrei Agrachev %A Davide Barilari %A Ugo Boscain %I SISSA %G en %U http://hdl.handle.net/1963/5877 %1 5747 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-05-30T13:23:26Z\r\nNo. of bitstreams: 1\r\n09M_2012_Barilari.pdf: 1146702 bytes, checksum: 28492a78df0fdf2435dd0606fdfc78f5 (MD5) %0 Journal Article %J International Mathematics Research Notices, vol. 22 (2012) , page 5063-5099 %D 2012 %T The KdV hierarchy: universality and a Painleve transcendent %A Tom Claeys %A Tamara Grava %K Small-Dispersion limit %X We study the Cauchy problem for the Korteweg-de Vries (KdV) hierarchy in the small dispersion limit where $\e\to 0$. For negative analytic initial data with a single negative hump, we prove that for small times, the solution is approximated by the solution to the hyperbolic transport equation which corresponds to $\e=0$. Near the time of gradient catastrophe for the transport equation, we show that the solution to the KdV hierarchy is approximated by a particular Painlev\'e transcendent. This supports Dubrovins universality conjecture concerning the critical behavior of Hamiltonian perturbations of hyperbolic equations. We use the Riemann-Hilbert approach to prove our results. %B International Mathematics Research Notices, vol. 22 (2012) , page 5063-5099 %I Oxford University Press %G en %U http://hdl.handle.net/1963/6921 %1 6902 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-05-29T08:08:55Z No. of bitstreams: 1 1101.2602v1.pdf: 327994 bytes, checksum: 5b5bbc9f9b74ce97c2bf5ae794698819 (MD5) %0 Journal Article %J Ann. Inst. H. Poincare Anal. Non Lineaire 29 (2012) 715-735 %D 2012 %T Linear elasticity obtained from finite elasticity by Gamma-convergence under weak coerciveness conditions %A Virginia Agostiniani %A Gianni Dal Maso %A Antonio DeSimone %K Nonlinear elasticity %X The energy functional of linear elasticity is obtained as G-limit of suitable rescalings of the energies of finite elasticity... %B Ann. Inst. H. Poincare Anal. Non Lineaire 29 (2012) 715-735 %I Gauthier-Villars;Elsevier %G en %U http://hdl.handle.net/1963/4267 %1 3996 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-26T15:11:45Z\\r\\nNo. of bitstreams: 1\\r\\nAgostiniani_DalMaso_30_M.pdf: 407057 bytes, checksum: 2009d1218f7735191a1c768a73b400a3 (MD5) %R 10.1016/j.anihpc.2012.04.001 %0 Journal Article %J Central European Journal of Mathematics 10, nr. 4 (2012) 1442-1454 %D 2012 %T On localization in holomorphic equivariant cohomology %A Ugo Bruzzo %A Vladimir Rubtsov %X We prove a localization formula for a \"holomorphic equivariant cohomology\"\r\nattached to the Atiyah algebroid of an equivariant holomorphic vector bundle.\r\nThis generalizes Feng-Ma, Carrell-Liebermann, Baum-Bott and K. Liu\'s\r\nlocalization formulas. %B Central European Journal of Mathematics 10, nr. 4 (2012) 1442-1454 %I Springer %G en %1 6534 %2 Mathematics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-04-05T07:23:50Z\nNo. of bitstreams: 1\n0910.2019v4.pdf: 208992 bytes, checksum: c23f79f0f70e7e94083b3ba5411f3c6c (MD5) %R 10.2478/s11533-012-0054-2 %0 Journal Article %J Central European Journal of Mathematics, Volume 10, Issue 4, August 2012, Pages 1442-1454 %D 2012 %T On localization in holomorphic equivariant cohomology %A Ugo Bruzzo %A Vladimir Rubtsov %K Lie algebroids %X We prove a localization formula for a "holomorphic equivariant cohomology" attached to the Atiyah algebroid of an equivariant holomorphic vector bundle. This generalizes Feng-Ma, Carrell-Liebermann, Baum-Bott and K. Liu's localization formulas. %B Central European Journal of Mathematics, Volume 10, Issue 4, August 2012, Pages 1442-1454 %I Springer %G en %U http://hdl.handle.net/1963/6584 %1 6543 %2 Mathematics %4 1 %$ Approved for entry into archive by Lucio Lubiana (lubiana@sissa.it) on 2013-04-08T12:16:34Z (GMT) No. of bitstreams: 0 %R 10.2478/s11533-012-0054-2 %0 Conference Proceedings %B Materials Research Society Symposium Proceedings. Volume 1403, 2012, Pages 125-130 %D 2012 %T Mathematical and numerical modeling of liquid crystal elastomer phase transition and deformation %A Mariarita de Luca %A Antonio DeSimone %K Artificial muscle %X Liquid crystal (in particular, nematic) elastomers consist of cross-linked flexible polymer chains with embedded stiff rod molecules that allow them to behave as a rubber and a liquid crystal. Nematic elastomers are characterized by a phase transition from isotropic to nematic past a temperature threshold. They behave as rubber at high temperature and show nematic behavior below the temperature threshold. Such transition is reversible. While in the nematic phase, the rod molecules are aligned along the direction of the "nematic director". This molecular rearrangement induces a stretch in the polymer chains and hence macroscopic spontaneous deformations. The coupling between nematic order parameter and deformation gives rise to interesting phenomena with a potential for new interesting applications. In the biological field, the ability to considerably change their length makes them very promising as artificial muscles actuators. Their tunable optical properties make them suitable, for example, as lenses for new imaging systems. We present a mathematical model able to describe the behavior of nematic elastomers and numerical simulations reproducing such peculiar behavior. We use a geometrically linear version of the Warner and Terentjev model [1] and consider cooling experiments and stretching experiments in the direction perpendicular to the one of the director at cross-linking. %B Materials Research Society Symposium Proceedings. Volume 1403, 2012, Pages 125-130 %I Cambridge University Press %@ 9781605113807 %G en %U http://hdl.handle.net/1963/7020 %1 7011 %2 Physics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-08-12T10:02:18Z No. of bitstreams: 0 %R 10.1557/opl.2012.249 %0 Journal Article %J IEEE Transactions on Automatic Control. Volume 57, Issue 8, 2012, Article number6189035, Pages 1898-1917 %D 2012 %T Modeling and control of quantum systems: An introduction %A Claudio Altafini %A Francesco Ticozzi %X The scope of this work is to provide a self-contained introduction to a selection of basic theoretical aspects in the modeling and control of quantum mechanical systems, as well as a brief survey on the main approaches to control synthesis. While part of the existing theory, especially in the open-loop setting, stems directly from classical control theory (most notably geometric control and optimal control), a number of tools specifically tailored for quantum systems have been developed since the 1980s, in order to take into account their distinctive features: the probabilistic nature of atomic-scale physical systems, the effect of dissipation and the irreversible character of the measurements have all proved to be critical in feedback-design problems. The relevant dynamical models for both closed and open quantum systems are presented, along with the main results on their controllability and stability. A brief review of several currently available control design methods is meant to provide the interested reader with a roadmap for further studies %B IEEE Transactions on Automatic Control. Volume 57, Issue 8, 2012, Article number6189035, Pages 1898-1917 %I Institute of Electrical and Electronics Engineers %G en %U http://hdl.handle.net/1963/6505 %1 6449 %2 Mathematics %4 1 %$ Approved for entry into archive by Lucio Lubiana (lubiana@sissa.it) on 2013-02-27T15:32:35Z (GMT) No. of bitstreams: 0 %R 10.1109/TAC.2012.2195830 %0 Journal Article %J Central European Journal of Mathematics 10, nr. 4 (2012) 1232 %D 2012 %T Moduli of symplectic instanton vector bundles of higher rank on projective space $\\mathbbP^3$ %A Ugo Bruzzo %A Dimitri Markushevich %A Alexander Tikhomirov %X Symplectic instanton vector bundles on the projective space $\\mathbb{P}^3$ constitute a natural generalization of mathematical instantons of rank 2. We study the moduli space $I_{n,r}$ of rank-$2r$ symplectic instanton vector bundles on $\\mathbb{P}^3$ with $r\\ge2$ and second Chern class $n\\ge r,\\ n\\equiv r({\\rm mod}2)$. We give an explicit construction of an irreducible component $I^*_{n,r}$ of this space for each such value of $n$ and show that $I^*_{n,r}$ has the expected dimension $4n(r+1)-r(2r+1)$. %B Central European Journal of Mathematics 10, nr. 4 (2012) 1232 %I SISSA %G en %U http://hdl.handle.net/1963/4656 %1 4406 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-10-10T09:47:24Z\r\nNo. of bitstreams: 1\r\n1109.2292v1.pdf: 243006 bytes, checksum: 39feac60657ccc939b3d688db3738e0e (MD5) %R 10.2478/s11533-012-0062-2 %0 Journal Article %J Quarterly Journal of Mathematics (2012) 63 (1): 41-86 %D 2012 %T Moduli spaces of noncommutative instantons: gauging away noncommutative parameters %A Simon Brain %A Giovanni Landi %X Using the theory of noncommutative geometry in a braided monoidal category, we improve upon a previous construction of noncommutative families of instantons of arbitrary charge on the deformed sphere S^4_\\\\theta. We formulate a notion of noncommutative parameter spaces for families of instantons and we explore what it means for such families to be gauge equivalent, as well as showing how to remove gauge parameters using a noncommutative quotient construction. Although the parameter spaces are a priori noncommutative, we show that one may always recover a classical parameter space by making an appropriate choice of gauge transformation. %B Quarterly Journal of Mathematics (2012) 63 (1): 41-86 %I Oxford University Press %G en_US %U http://hdl.handle.net/1963/3777 %1 548 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-10-26T14:39:30Z\\r\\nNo. of bitstreams: 1\\r\\n0909.4402.pdf: 469021 bytes, checksum: bbcda76215b8bb90a5704b81326e9dde (MD5) %R 10.1093/qmath/haq036 %0 Report %D 2012 %T N=2 gauge theories on toric singularities, blow-up formulae and W-algebrae %A Giulio Bonelli %A Kazunobu Maruyoshi %A Alessandro Tanzini %A Futoshi Yagi %X We compute the Nekrasov partition function of gauge theories on the\\r\\n(resolved) toric singularities C^2/\\\\Gamma in terms of blow-up formulae. We\\r\\ndiscuss the expansion of the partition function in the \\\\epsilon_1,\\\\epsilon_2\\r\\n\\\\to 0 limit along with its modular properties and how to derive them from the\\r\\nM-theory perspective. On the two-dimensional conformal field theory side, our results can be interpreted in terms of representations of the direct sum of\\r\\nHeisenberg plus W_N-algebrae with suitable central charges, which can be\\r\\ncomputed from the fan of the resolved toric variety. We provide a check of this\\r\\ncorrespondence by computing the central charge of the two-dimensional theory from the anomaly polynomial of M5-brane theory. Upon using the AGT\\r\\ncorrespondence our results provide a candidate for the conformal blocks and three-point functions of a class of the two-dimensional CFTs which includes parafermionic theories. %I SISSA %G en %U http://hdl.handle.net/1963/6114 %1 6012 %2 Physics %3 Elementary Particle Theory %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-08-10T06:21:05Z\\nNo. of bitstreams: 1\\n1208.0790v1.pdf: 349834 bytes, checksum: 8179977a55566b1b83b7814be798f5f9 (MD5) %0 Journal Article %J Math. Models Methods Appl. Sci. 22, 1150016 (2012) %D 2012 %T Nonlinear thin-walled beams with a rectangular cross-section-Part I %A Lorenzo Freddi %A Maria Giovanna Mora %A Roberto Paroni %X Our aim is to rigorously derive a hierarchy of one-dimensional models for thin-walled beams with rectangular cross-section, starting from three-dimensional nonlinear elasticity. The different limit models are distinguished by the different scaling of the elastic energy and of the ratio between the sides of the cross-section. In this paper we report the first part of our results. %B Math. Models Methods Appl. Sci. 22, 1150016 (2012) %I World Scientific %G en_US %U http://hdl.handle.net/1963/4104 %1 300 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-11-17T08:45:48Z\\r\\nNo. of bitstreams: 1\\r\\nFreddi_79M.pdf: 331698 bytes, checksum: 3b0d6e3d51984a8e8222753a57064ee9 (MD5) %R 10.1142/S0218202511500163 %0 Journal Article %J Communications in Mathematical Physics, Volume 315, Issue 1, September 2012, Pages 1-37 %D 2012 %T Non-uniqueness results for critical metrics of regularized determinants in four dimensions %A Matthew Gursky %A Andrea Malchiodi %X The regularized determinant of the Paneitz operator arises in quantum gravity (see Connes 1994, IV.4.$\gamma$). An explicit formula for the relative determinant of two conformally related metrics was computed by Branson in Branson (1996). A similar formula holds for Cheeger's half-torsion, which plays a role in self-dual field theory (see Juhl, 2009), and is defined in terms of regularized determinants of the Hodge laplacian on $p$-forms ($p < n/2$). In this article we show that the corresponding actions are unbounded (above and below) on any conformal four-manifold. We also show that the conformal class of the round sphere admits a second solution which is not given by the pull-back of the round metric by a conformal map, thus violating uniqueness up to gauge equivalence. These results differ from the properties of the determinant of the conformal Laplacian established in Chang and Yang (1995), Branson, Chang, and Yang (1992), and Gursky (1997). We also study entire solutions of the Euler-Lagrange equation of $\log \det P$ and the half-torsion $\tau_h$ on $\mathbb{R}^4 \setminus {0}$, and show the existence of two families of periodic solutions. One of these families includes Delaunay-type solutions. %B Communications in Mathematical Physics, Volume 315, Issue 1, September 2012, Pages 1-37 %I Springer %G en %U http://hdl.handle.net/1963/6559 %1 6488 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Andrea Malchiodi (malchiod@sissa.it) on 2013-03-14T10:25:46Z No. of bitstreams: 1 1105.3762v3.pdf: 658857 bytes, checksum: 2821cb9caed2f5cda3b406c745b73009 (MD5) %R 10.1007/s00220-012-1535-7 %0 Journal Article %J Acta Geotechnica, Volume 7, Issue 3, September 2012, Pages 219-237 %D 2012 %T Numerical modelling of installation effects for diaphragm walls in sand %A Riccardo Conti %A Luca de Sanctis %A Giulia M.B. Viggiani %K Constitutive relations %X The scopes of this work are to study the mechanisms of load transfer and the deformations of the ground during slurry trenching and concreting in dry sand and to evaluate their effects on service structural loads, wall deflections and ground displacements behind the wall caused by subsequent excavation. A series of three-dimensional finite element analyses was carried out modelling the installation of diaphragm walls consisting of panels of different length. The soil was modelled as either linearly elastic-perfectly plastic or incrementally non-linear (hypoplastic) with elastic strain range. Plane strain analyses of diaphragm walls of identical cross section were also carried out in which wall installation was either modelled or the wall was wished in place (WIP). The analyses predict ground movements consistent with the experimental observations both in magnitude and trend. The results also show that the maximum horizontal wall deflections and structural loads reduce with increasing panel aspect ratio towards a minimum which is about twice the value computed for WIP analyses. Panel aspect ratios should be larger than about three to take advantage of the three-dimensional effects. The pattern and magnitude of surface vertical displacements obtained from linearly elastic-perfectly plastic analyses, no matter whether three- or two-dimensional, are unrealistic. %B Acta Geotechnica, Volume 7, Issue 3, September 2012, Pages 219-237 %I Springer %G en %U http://hdl.handle.net/1963/6934 %1 6916 %2 Mathematics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-05-30T10:23:32Z No. of bitstreams: 0 %R 10.1007/s11440-011-0157-0 %0 Journal Article %J Physica D 241, nr. 23-24 (2012): 2246-2264 %D 2012 %T Numerical study of the small dispersion limit of the Korteweg-de Vries equation and asymptotic solutions %A Tamara Grava %A Christian Klein %K Korteweg-de Vries equation %X We study numerically the small dispersion limit for the Korteweg-de Vries (KdV) equation $u_t+6uu_x+\epsilon^{2}u_{xxx}=0$ for $\epsilon\ll1$ and give a quantitative comparison of the numerical solution with various asymptotic formulae for small $\epsilon$ in the whole $(x,t)$-plane. The matching of the asymptotic solutions is studied numerically. %B Physica D 241, nr. 23-24 (2012): 2246-2264 %I Elsevier %G en %1 7069 %2 Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-09-16T14:49:23Z No. of bitstreams: 1 1202.0962v2.pdf: 2652650 bytes, checksum: d8678338138745b35d8515af39f85d18 (MD5) %R 10.1016/j.physd.2012.04.001 %0 Journal Article %J International Journal of Non-Linear mechanics 47 nr. 2 (2012) 402-412 %D 2012 %T Ogden-type energies for nematic elastomers %A Virginia Agostiniani %A Antonio DeSimone %K Nonlinear elasticity %X Ogden-type extensions of the free-energy densities currently used to model the mechanical behavior of nematic elastomers are proposed and analyzed. Based on a multiplicative decomposition of the deformation gradient into an elastic and a spontaneous or remanent part, they provide a suitable framework to study the stiffening response at high imposed stretches. Geometrically linear versions of the models (Taylor expansions at order two) are provided and discussed. These small strain theories provide a clear illustration of the geometric structure of the underlying energy landscape (the energy grows quadratically with the distance from a non-convex set of spontaneous strains or energy wells). The comparison between small strain and finite deformation theories may also be useful in the opposite direction, inspiring finite deformation generalizations of small strain theories currently used in the mechanics of active and phase-transforming materials. The energy well structure makes the free-energy densities non-convex. Explicit quasi-convex envelopes are provided, and applied to compute the stiffening response of a specimen tested in plane strain extension experiments (pure shear). %B International Journal of Non-Linear mechanics 47 nr. 2 (2012) 402-412 %I Elsevier %G en %1 6971 %2 Mathematics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-07-15T14:33:38Z No. of bitstreams: 0 %R 10.1016/j.ijnonlinmec.2011.10.001 %0 Report %D 2012 %T Pfaffian representations of cubic surfaces %A Fabio Tanturri %I SISSA %1 6203 %2 Mathematics %3 Mathematical Physics %0 Journal Article %J Physica D: Nonlinear Phenomena, Volume 241, Issue 23-24, 1 December 2012, Pages 2188-2203 %D 2012 %T Poles Distribution of PVI Transcendents close to a Critical Point (summer 2011) %A Davide Guzzetti %K Painleve' equations %X The distribution of the poles of Painlevé VI transcendents associated to semi-simple Frobenius manifolds is determined close to a critical point. It is shown that the poles accumulate at the critical point,asymptotically along two rays. As an example, the Frobenius manifold given by the quantum cohomology of CP2 is considered. The general PVI is also considered. %B Physica D: Nonlinear Phenomena, Volume 241, Issue 23-24, 1 December 2012, Pages 2188-2203 %I Elsevier %G en %U http://hdl.handle.net/1963/6526 %1 6469 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Davide Guzzetti (guzzetti@sissa.it) on 2013-03-12T10:23:20Z No. of bitstreams: 1 1104.5066v3.pdf: 539839 bytes, checksum: 5e2f0aa0a56736f91219709b51d0a970 (MD5) %R doi:10.1016/j.physd.2012.02.015 %0 Journal Article %J BMC Systems Biology. 29 August 2012, Page 115 %D 2012 %T Predicting and characterizing selective multiple drug treatments for metabolic diseases and cancer. %A Giuseppe Facchetti %A Claudio Altafini %A Mattia Zampieri %X Background: In the field of drug discovery, assessing the potential of multidrug therapies is a difficult task because of the combinatorial complexity (both theoretical and experimental) and because of the requirements on the selectivity of the therapy. To cope with this problem, we have developed a novel method for the systematic in silico investigation of synergistic effects of currently available drugs on genome-scale metabolic networks. The algorithm finds the optimal combination of drugs which guarantees the inhibition of an objective function, while minimizing the side effect on the overall network. Results: Two different applications are considered: finding drug synergisms for human metabolic diseases (like diabetes, obesity and hypertension) and finding antitumoral drug combinations with minimal side effect on the normal human metabolism.The results we obtain are consistent with some of the available therapeutic indications and predict some new multiple drug treatments.A cluster analysis on all possible interactions among the currently available drugs indicates a limited variety on the metabolic targets for the approved drugs. Conclusion: The in silico prediction of drug synergism can represent an important tool for the repurposing of drug in a realistic perspective which considers also the selectivty of the therapy. Moreover, for a more profitable exploitation of drug-drug interactions, also drugs which show a too low efficacy but which have a non-common mechanism of action, can be reconsider as potential ingredients of new multicompound therapeutic indications.Needless to say the clues provided by a computational study like ours need in any case to be thoroughly evaluated experimentally. %B BMC Systems Biology. 29 August 2012, Page 115 %I BioMed Central %G en %U http://hdl.handle.net/1963/6515 %1 6450 %2 Mathematics %4 1 %$ Submitted by Claudio Altafini (altafini@sissa.it) on 2013-02-27T13:12:49Z\nNo. of bitstreams: 0 %R doi:10.1186/1752-0509-6-115 %0 Journal Article %J Calculus of variations and partial differential equations 44 (2012) 495-541 %D 2012 %T Quasistatic evolution for Cam-Clay plasticity: properties of the viscosity solution %A Gianni Dal Maso %A Antonio DeSimone %A Francesco Solombrino %X Cam-Clay plasticity is a well established model for the description of the mechanics of fine grained soils. As solutions can develop discontinuities in time, a weak notion of solution, in terms of a rescaled time s , has been proposed in [8] to give a meaning to this discontinuous evolution. In this paper we first prove that this rescaled evolution satisfies the flow-rule for the rate of plastic strain, in a suitable measure-theoretical sense. In the second part of the paper we consider the behavior of the evolution in terms of the original time variable t . We prove that the unrescaled solution satisfies an energy-dissipation balance and an evolution law for the internal variable, which can be expressed in terms of integrals depending only on the original time. Both these integral identities contain terms concentrated on the jump times, whose size can only be determined by looking at the rescaled formulation. %B Calculus of variations and partial differential equations 44 (2012) 495-541 %I Springer %G en_US %U http://hdl.handle.net/1963/3900 %1 809 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-07-26T09:17:50Z\\r\\nNo. of bitstreams: 1\\r\\nSolombrino_46M.pdf: 382911 bytes, checksum: dd118cc7f80d4cb1902713eb18747ac6 (MD5) %R 10.1007/s00526-011-0443-6 %0 Journal Article %J SIAM Journal on Mathematical Analysis 44, nr. 1 (2012) 245-292 %D 2012 %T Quasistatic evolution in non-associative plasticity - the cap models %A Jean-Francois Babadjian %A Gilles A. Francfort %A Maria Giovanna Mora %K Elasto-plasticity %X Non-associative elasto-plasticity is the working model of plasticity for soil and rocks mechanics. Yet, it is usually viewed as non-variational. In this work, we prove a contrario the existence of a variational evolution for such a model under a natural capping assumption on the hydrostatic stresses and a less natural mollification of the stress admissibility constraint. The obtained elasto-plastic evolution is expressed for times that are conveniently rescaled. %B SIAM Journal on Mathematical Analysis 44, nr. 1 (2012) 245-292 %I SIAM %G en %U http://hdl.handle.net/1963/4139 %1 3879 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-15T12:13:15Z No. of bitstreams: 1 Bab-Fra-Mora_05M.pdf: 420336 bytes, checksum: cf8a2e6bd6c333fb5b6b130ae22de0a7 (MD5) %R 10.1137/110823511 %0 Report %D 2012 %T A Quasistatic evolution model for perfectly plastic plates derived by Gamma-convergence %A Elisa Davoli %A Maria Giovanna Mora %K Gamma-convergence %X The subject of this paper is the rigorous derivation of a quasistatic evolution model for a linearly elastic - perfectly plastic thin plate. As the thickness of the plate tends to zero, we prove via Gamma-convergence techniques that solutions to the three-dimensional quasistatic evolution problem of Prandtl-Reuss elastoplasticity converge to a quasistatic evolution of a suitable reduced model. In this limiting model the admissible displacements are of Kirchhoff-Love type and the stretching and bending components of the stress are coupled through a plastic flow rule. Some equivalent formulations of the limiting problem in rate form are derived, together with some two-dimensional characterizations for suitable choices of the data. %I SISSA %G en %U http://hdl.handle.net/1963/5673 %1 5519 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-04-04T06:51:03Z\\nNo. of bitstreams: 1\\nDavoli-Mora.pdf: 466175 bytes, checksum: 1a2615326bd1d5b68d86db9f31b10aa4 (MD5) %0 Conference Proceedings %B European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) J. Eberhardsteiner et.al. (eds.), Vienna, Austria, 10-14 sept. 2012 %D 2012 %T Reduction strategies for PDE-constrained oprimization problems in Haemodynamics %A Gianluigi Rozza %A Andrea Manzoni %A Federico Negri %K inverse problems %X Solving optimal control problems for many different scenarios obtained by varying a set of parameters in the state system is a computationally extensive task. In this paper we present a new reduced framework for the formulation, the analysis and the numerical solution of parametrized PDE-constrained optimization problems. This framework is based on a suitable saddle-point formulation of the optimal control problem and exploits the reduced basis method for the rapid and reliable solution of parametrized PDEs, leading to a relevant computational reduction with respect to traditional discretization techniques such as the finite element method. This allows a very efficient evaluation of state solutions and cost functionals, leading to an effective solution of repeated optimal control problems, even on domains of variable shape, for which a further (geometrical) reduction is pursued, relying on flexible shape parametrization techniques. This setting is applied to the solution of two problems arising from haemodynamics, dealing with both data reconstruction and data assimilation over domains of variable shape,\\r\\nwhich can be recast in a common PDE-constrained optimization formulation. %B European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) J. Eberhardsteiner et.al. (eds.), Vienna, Austria, 10-14 sept. 2012 %G en %U http://hdl.handle.net/1963/6338 %1 6268 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Gianluigi Rozza (grozza@sissa.it) on 2012-12-13T16:30:48Z\\r\\nNo. of bitstreams: 1\\r\\npaper_ECCOMAS2012_AM_SISSAreport.pdf: 4599005 bytes, checksum: 014a5a01276f25177386ad374a5917c8 (MD5) %0 Journal Article %J Proceedings of the National Academy of Sciences of the United States of America. Volume 109, Issue 44, 30 October 2012, Pages 17874-17879 %D 2012 %T Reverse engineering the euglenoid movement %A Marino Arroyo %A Luca Heltai %A Daniel Millán %A Antonio DeSimone %K microswimmers %X Euglenids exhibit an unconventional motility strategy amongst unicellular eukaryotes, consisting of large-amplitude highly concerted deformations of the entire body (euglenoid movement or metaboly). A plastic cell envelope called pellicle mediates these deformations. Unlike ciliary or flagellar motility, the biophysics of this mode is not well understood, including its efficiency and molecular machinery. We quantitatively examine video recordings of four euglenids executing such motions with statistical learning methods. This analysis reveals strokes of high uniformity in shape and pace. We then interpret the observations in the light of a theory for the pellicle kinematics, providing a precise understanding of the link between local actuation by pellicle shear and shape control. We systematically understand common observations, such as the helical conformations of the pellicle, and identify previously unnoticed features of metaboly. While two of our euglenids execute their stroke at constant body volume, the other two exhibit deviations of about 20% from their average volume, challenging current models of low Reynolds number locomotion. We find that the active pellicle shear deformations causing shape changes can reach 340%, and estimate the velocity of the molecular motors. Moreover, we find that metaboly accomplishes locomotion at hydrodynamic efficiencies comparable to those of ciliates and flagellates. Our results suggest new quantitative experiments, provide insight into the evolutionary history of euglenids, and suggest that the pellicle may serve as a model for engineered active surfaces with applications in microfluidics. %B Proceedings of the National Academy of Sciences of the United States of America. Volume 109, Issue 44, 30 October 2012, Pages 17874-17879 %G en %U http://hdl.handle.net/1963/6444 %1 6380 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Luca Heltai (heltai@sissa.it) on 2013-02-01T17:29:31Z\\nNo. of bitstreams: 0 %R 10.1073/pnas.1213977109 %0 Journal Article %D 2012 %T A Review on The Sixth Painleve\' Equation %A Davide Guzzetti %K Painlevé equation %X For the Painlev\\\'e 6 transcendents, we provide a unitary description of the\r\ncritical behaviours, the connection formulae, their complete tabulation, and\r\nthe asymptotic distribution of the poles close to a critical point. %I SISSA %G en %U http://hdl.handle.net/1963/6525 %1 6470 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Davide Guzzetti (guzzetti@sissa.it) on 2013-03-12T10:24:43Z\nNo. of bitstreams: 1\n1210.0311v1.pdf: 283505 bytes, checksum: d5f401efb5eec8b4689b090dbcca6d84 (MD5) %0 Journal Article %J Systems and Control Letters. Volume 61, Issue 2, February 2012, Pages 347-353 %D 2012 %T On robust Lie-algebraic stability conditions for switched linear systems %A Andrei Agrachev %A Yurij Baryshnikov %A Daniel Liberzon %X This paper presents new sufficient conditions for exponential stability of switched linear systems under arbitrary switching, which involve the commutators (Lie brackets) among the given matrices generating the switched system. The main novelty feature of these stability criteria is that, unlike their earlier counterparts, they are robust with respect to small perturbations of the system parameters. %B Systems and Control Letters. Volume 61, Issue 2, February 2012, Pages 347-353 %G en %U http://hdl.handle.net/1963/6455 %1 6400 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-02-05T14:15:25Z\\nNo. of bitstreams: 0 %R 10.1016/j.sysconle.2011.11.016 %0 Journal Article %J Communications in Mathematical Physics 313 (2012) 1-33 %D 2012 %T SBV regularity for genuinely nonlinear, strictly hyperbolic systems of conservation laws in one space dimension %A Stefano Bianchini %A Laura Caravenna %B Communications in Mathematical Physics 313 (2012) 1-33 %I Springer %G en_US %U http://hdl.handle.net/1963/4091 %1 313 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-10-19T09:31:49Z\\r\\nNo. of bitstreams: 1\\r\\nBianchini_Caravenna_71M_2010.pdf: 591519 bytes, checksum: 388c1d8be60af95097574c718b4708b2 (MD5) %R 10.1007/s00220-012-1480-5 %0 Journal Article %J Siam Journal on Mathematical Analysis 44, nr. 3 (2012) 2179-2203 %D 2012 %T SBV regularity for Hamilton-Jacobi equations with Hamiltonian depending on (t,x) %A Stefano Bianchini %A Daniela Tonon %B Siam Journal on Mathematical Analysis 44, nr. 3 (2012) 2179-2203 %I SISSA %G en %U http://hdl.handle.net/1963/4168 %1 3890 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-20T13:28:47Z\r\nNo. of bitstreams: 1\r\nBianchini_Tonon_13M.pdf: 249849 bytes, checksum: 461aecb2ce41d2bff011ba0062ed1cfb (MD5) %R 10.1137/110827272 %0 Journal Article %J Acta Mathematica Scientia, Volume 32, Issue 1, January 2012, Pages 380-388 %D 2012 %T SBV regularity of genuinely nonlinear hyperbolic systems of conservation laws in one space dimension %A Stefano Bianchini %K Hyperbolic systems %X The problem of the presence of Cantor part in the derivative of a solution to a hyperbolic system of conservation laws is considered. An overview of the techniques involved in the proof is given, and a collection of related problems concludes the paper. Key words hyperbolic systems; conservation laws; SBV; regularity %B Acta Mathematica Scientia, Volume 32, Issue 1, January 2012, Pages 380-388 %I Elsevier %G en %U http://hdl.handle.net/1963/6535 %1 6510 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-03-21T08:22:40Z\nNo. of bitstreams: 0 %R 10.1016/S0252-9602(12)60024-1 %0 Journal Article %J Journal of Mathematical Analysis and Applications 391 (2012) 190-208 %D 2012 %T SBV-like regularity for Hamilton-Jacobi equations with a convex Hamiltonian %A Stefano Bianchini %A Daniela Tonon %B Journal of Mathematical Analysis and Applications 391 (2012) 190-208 %I SISSA %G en %U http://hdl.handle.net/1963/4591 %1 4352 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-10-07T11:24:37Z\\r\\nNo. of bitstreams: 1\\r\\n45M_Tonon_Bianchini.pdf: 179519 bytes, checksum: c157fc19ae52c2fb8bcd2ca28815d26e (MD5) %R 10.1016/j.jmaa.2012.02.017 %0 Journal Article %J International Journal Numerical Methods Biomedical Engineering %D 2012 %T Simulation-based uncertainty quantification of human arterial network hemodynamics %A Peng Chen %A Alfio Quarteroni %A Gianluigi Rozza %K uncertainty quantification, mathematical modelling of the cardiovascular system, fluid-structure interaction %X This work aims at identifying and quantifying uncertainties from various sources in human cardiovascular\r\nsystem based on stochastic simulation of a one dimensional arterial network. A general analysis of\r\ndifferent uncertainties and probability characterization with log-normal distribution of these uncertainties\r\nis introduced. Deriving from a deterministic one dimensional fluid structure interaction model, we establish\r\nthe stochastic model as a coupled hyperbolic system incorporated with parametric uncertainties to describe\r\nthe blood flow and pressure wave propagation in the arterial network. By applying a stochastic collocation\r\nmethod with sparse grid technique, we study systemically the statistics and sensitivity of the solution with\r\nrespect to many different uncertainties in a relatively complete arterial network with potential physiological\r\nand pathological implications for the first time. %B International Journal Numerical Methods Biomedical Engineering %I Wiley %G en %1 6467 %2 Mathematics %4 1 %# MAT/08 ANALISI NUMERICA %$ Submitted by Gianluigi Rozza (grozza@sissa.it) on 2013-03-07T12:33:02Z\nNo. of bitstreams: 1\nreport.pdf: 1605405 bytes, checksum: bb12cf074ce32a80567a0cde0c0861db (MD5) %0 Journal Article %J Nonlinearity %D 2012 %T Sobolev quasi-periodic solutions of multidimensional wave equations with a multiplicative potential %A Massimiliano Berti %A Philippe Bolle %X We prove the existence of quasi-periodic solutions for wave equations with a multiplicative potential on T d , d ≥ 1, and finitely differentiable nonlinearities, quasi-periodically forced in time. The only external parameter is the length of the frequency vector. The solutions have Sobolev regularity both in time and space. The proof is based on a Nash-Moser iterative scheme as in [5]. The key tame estimates for the inverse linearized operators are obtained by a multiscale inductive argument, which is more difficult than for NLS due to the dispersion relation of the wave equation. We prove the 'separation properties' of the small divisors assuming weaker non-resonance conditions than in [11]. © 2012 IOP Publishing Ltd. %B Nonlinearity %V 25 %P 2579-2613 %G eng %R 10.1088/0951-7715/25/9/2579 %0 Journal Article %J Int Math Res Notices (2012) 2012 (6): 1352-1413 %D 2012 %T Solving the Sixth Painlevé Equation: Towards the Classification of all the Critical Behaviors and the Connection Formulae %A Davide Guzzetti %X The critical behavior of a three real parameter class of solutions of the\\r\\nsixth Painlev\\\\\\\'e equation is computed, and parametrized in terms of monodromy\\r\\ndata of the associated $2\\\\times 2$ matrix linear Fuchsian system of ODE. The\\r\\nclass may contain solutions with poles accumulating at the critical point. The\\r\\nstudy of this class closes a gap in the description of the transcendents in one\\r\\nto one correspondence with the monodromy data. These transcendents are reviewed in the paper. Some formulas that relate the monodromy data to the critical behaviors of the four real (two complex) parameter class of solutions are\\r\\nmissing in the literature, so they are computed here. A computational procedure to write the full expansion of the four and three real parameter class of solutions is proposed. %B Int Math Res Notices (2012) 2012 (6): 1352-1413 %I Oxford University Press %G en %U http://hdl.handle.net/1963/6093 %1 5979 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-08-02T13:30:44Z\\nNo. of bitstreams: 1\\n1010.1895v3.pdf: 424524 bytes, checksum: b558cd4e4da76831f67255b275392840 (MD5) %R 10.1093/imrn/rnr071 %0 Thesis %D 2012 %T Some aspects of spinors – classical and noncommutative %A Giacomo Dossena %I SISSA %G en %U http://hdl.handle.net/1963/6317 %1 6218 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Giacomo Dossena (dossena@sissa.it) on 2012-11-13T11:13:08Z\\nNo. of bitstreams: 1\\nthesis.pdf: 1569621 bytes, checksum: 1ab89dce9cdc2097b3692da5a63ad82b (MD5) %0 Journal Article %J International Journal of Geometric Methods in Modern Physics, Volume 9, Issue 2, March 2012, Article number1260018 %D 2012 %T Some remarks on quantum mechanics %A Gianfausto Dell'Antonio %K Quantum mechanics %X We discuss the similarities and differences between the formalism of Hamiltonian Classical Mechanics and of Quantum Mechanics and exemplify the differences through an analysis of tracks in a cloud chamber. %B International Journal of Geometric Methods in Modern Physics, Volume 9, Issue 2, March 2012, Article number1260018 %I World Scientific Publishing %G en %U http://hdl.handle.net/1963/7018 %1 7013 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-08-12T10:45:49Z No. of bitstreams: 0 %R 10.1142/S0219887812600183 %0 Journal Article %J Rev. Math. Phys. 24 (2012), 1250017 %D 2012 %T Stability for a System of N Fermions Plus a Different Particle with Zero-Range Interactions %A Michele Correggi %A Gianfausto Dell'Antonio %A Domenico Finco %A Alessandro Michelangeli %A Alessandro Teta %X We study the stability problem for a non-relativistic quantum system in\\r\\ndimension three composed by $ N \\\\geq 2 $ identical fermions, with unit mass,\\r\\ninteracting with a different particle, with mass $ m $, via a zero-range\\r\\ninteraction of strength $ \\\\alpha \\\\in \\\\R $. We construct the corresponding\\r\\nrenormalised quadratic (or energy) form $ \\\\form $ and the so-called\\r\\nSkornyakov-Ter-Martirosyan symmetric extension $ H_{\\\\alpha} $, which is the\\r\\nnatural candidate as Hamiltonian of the system. We find a value of the mass $\\r\\nm^*(N) $ such that for $ m > m^*(N)$ the form $ \\\\form $ is closed and bounded from below. As a consequence, $ \\\\form $ defines a unique self-adjoint and bounded from below extension of $ H_{\\\\alpha}$ and therefore the system is stable. On the other hand, we also show that the form $ \\\\form $ is unbounded from below for $ m < m^*(2)$. In analogy with the well-known bosonic case, this suggests that the system is unstable for $ m < m^*(2)$ and the so-called Thomas effect occurs. %B Rev. Math. Phys. 24 (2012), 1250017 %I World Scientific %G en %U http://hdl.handle.net/1963/6069 %1 5955 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-08-02T07:19:59Z\\nNo. of bitstreams: 1\\n1201.5740v1.pdf: 303047 bytes, checksum: eb2df0afd547514c235422e82f494584 (MD5) %R 10.1142/S0129055X12500171 %0 Conference Paper %B 17th Int. Conf. Ships Shipp. Res. %D 2012 %T A stable semi-lagrangian potential method for the simulation of ship interaction with unsteady and nonlinear waves %A Mola, Andrea %A Heltai, Luca %A Desimone, Antonio %B 17th Int. Conf. Ships Shipp. Res. %G eng %0 Journal Article %J Journal of Dynamical and Control Systems. Volume 18, Issue 1, January 2012, Pages 21-44 %D 2012 %T Sub-Riemannian structures on 3D Lie groups %A Andrei Agrachev %A Davide Barilari %X We give a complete classification of left-invariant sub-Riemannian structures\r\non three dimensional Lie groups in terms of the basic differential invariants.\r\nAs a corollary we explicitly find a sub-Riemannian isometry between the\r\nnonisomorphic Lie groups SL(2) and $A^+(\\R)\\times S^1$, where $A^+(\\R)$ denotes\r\nthe group of orientation preserving affine maps on the real line. %B Journal of Dynamical and Control Systems. Volume 18, Issue 1, January 2012, Pages 21-44 %I SISSA %G en %U http://hdl.handle.net/1963/6453 %1 6397 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-02-05T13:48:29Z\r\nNo. of bitstreams: 1\r\n1007.4970v2.pdf: 453953 bytes, checksum: 4330325299743bad4afe9f1ac7121e21 (MD5) %R 10.1007/s10883-012-9133-8 %0 Journal Article %J Proceedings of the London Mathematical Society, Volume 105, Issue 3, September 2012, Pages 622-660 %D 2012 %T Systems of Quadratic Inequalities %A Andrei Agrachev %A Antonio Lerario %X We present a spectral sequence which efficiently computes Betti numbers of a closed semi-algebraic subset of RP^n defined by a system of quadratic inequalities and the image of the homology homomorphism induced by the inclusion of this subset in RP^n. We do not restrict ourselves to the term E_2 of the spectral sequence and give a simple explicit formula for the differential d_2. %B Proceedings of the London Mathematical Society, Volume 105, Issue 3, September 2012, Pages 622-660 %I SISSA %G en %U http://hdl.handle.net/1963/7072 %1 7066 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-09-16T10:02:51Z No. of bitstreams: 1 1012.5731v2.pdf: 367584 bytes, checksum: 136c7bc2abeeb2a239c15689929eae30 (MD5) %R DOI: 10.1112/plms/pds010 %0 Journal Article %J Nonlinearity, Volume 25, Issue 12, December 2012, Pages 3235-3276 %D 2012 %T Tabulation of Painlevé 6 transcendents %A Davide Guzzetti %X The critical and asymptotic behaviors of solutions of the sixth Painlev'e equation PVI, obtained in the framework of the monodromy preserving deformation method, and their explicit parametrization in terms of monodromy data, are tabulated. %B Nonlinearity, Volume 25, Issue 12, December 2012, Pages 3235-3276 %I IOP Publishing %G en %U http://hdl.handle.net/1963/6520 %1 6471 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Davide Guzzetti (guzzetti@sissa.it) on 2013-03-12T10:28:08Z No. of bitstreams: 1 1108.3401v3.pdf: 449170 bytes, checksum: f6436fe13133f97b3b49bb7d11e23004 (MD5) %R 10.1088/0951-7715/25/12/3235 %0 Journal Article %J Proc. R. Soc. A 8 March 2012 vol. 468 no. 2139 701-719 %D 2012 %T Thermodynamic phase transitions and shock singularities %A Giuseppe De Nittis %A Antonio Moro %X We show that under rather general assumptions on the form of the entropy\\r\\nfunction, the energy balance equation for a system in thermodynamic equilibrium is equivalent to a set of nonlinear equations of hydrodynamic type. This set of equations is integrable via the method of the characteristics and it provides the equation of state for the gas. The shock wave catastrophe set identifies the phase transition. A family of explicitly solvable models of\\r\\nnon-hydrodynamic type such as the classical plasma and the ideal Bose gas are\\r\\nalso discussed. %B Proc. R. Soc. A 8 March 2012 vol. 468 no. 2139 701-719 %I The Royal Society %G en %U http://hdl.handle.net/1963/6090 %1 5978 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-08-02T11:53:22Z\\nNo. of bitstreams: 1\\n1107.0394v2.pdf: 610849 bytes, checksum: be0b8d83ff44e0468c3133f7ab3ca18d (MD5) %R 10.1098/rspa.2011.0459 %0 Report %D 2012 %T Topological sensitivity analysis for high order elliptic operators %A Samuel Amstutz %A Antonio André Novotny %A Nicolas Van Goethem %K Topological derivative, Elliptic operators, Polarization tensor %X The topological derivative is defined as the first term of the asymptotic expansion of a given shape functional with respect to a small parameter that measures the size of a singular domain perturbation. It has applications in many different fields such as shape and topology optimization, inverse problems, image processing and mechanical modeling including synthesis and/or optimal design of microstructures, fracture mechanics sensitivity analysis and damage evolution modeling. The topological derivative has been fully developed for a wide range of second order differential operators. In this paper we deal with the topological asymptotic expansion of a class of shape functionals associated with elliptic differential operators of order 2m, m>=1. The general structure of the polarization tensor is derived and the concept of degenerate polarization tensor is introduced. We provide full mathematical justifications for the derived formulas, including precise estimates of remainders. %I SISSA %G en %U http://hdl.handle.net/1963/6343 %1 6272 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Nicolas Van Goethem (vangoeth@sissa.it) on 2012-12-14T17:45:48Z No. of bitstreams: 1 Degenerate_sub.pdf: 479352 bytes, checksum: eefab8b4e64b0ef0c7d7f0e16d529008 (MD5) %0 Journal Article %J Computer Methods in Applied Mechanics and Engineering. Volume 229-232, 1 July 2012, Pages 110-127 %D 2012 %T Variational implementation of immersed finite element methods %A Luca Heltai %A Francesco Costanzo %K Turbulent flow %B Computer Methods in Applied Mechanics and Engineering. Volume 229-232, 1 July 2012, Pages 110-127 %I Elsevier %G en %U http://hdl.handle.net/1963/6462 %1 6389 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Lucio Lubiana (lubiana@sissa.it) on 2013-02-04T16:21:56Z\\nNo. of bitstreams: 0 %R 10.1016/j.cma.2012.04.001 %0 Journal Article %J JHEP 6 (2012) 178 %D 2012 %T Vertices, Vortices & Interacting Surface Operators %A Giulio Bonelli %A Alessandro Tanzini %A Jian Zhao %X We show that the vortex moduli space in non-abelian supersymmetric N=(2,2) gauge theories on the two dimensional plane with adjoint and anti-fundamental matter can be described as an holomorphic submanifold of the instanton moduli space in four dimensions. The vortex partition functions for these theories are computed via equivariant localization. We show that these coincide with the field theory limit of the topological vertex on the strip with boundary conditions corresponding to column diagrams. Moreover, we resum the field theory limit of the vertex partition functions in terms of generalized hypergeometric functions formulating their AGT dual description as interacting surface operators of simple type. Analogously we resum the topological open string amplitudes in terms of q-deformed generalized hypergeometric functions proving that they satisfy appropriate finite difference equations. %B JHEP 6 (2012) 178 %I Springer %G en %U http://hdl.handle.net/1963/6571 %1 6528 %2 Mathematics %4 1 %$ Submitted by Alessandro Tanzini (tanzini@sissa.it) on 2013-04-04T10:06:09Z No. of bitstreams: 1 1102.0184v3.pdf: 260202 bytes, checksum: 3b7f6a998608e4aa8e4cc8517410c2af (MD5) %0 Journal Article %J JHEP 06(2012)178 %D 2012 %T Vertices, vortices & interacting surface operators %A Giulio Bonelli %A Alessandro Tanzini %A Zhao Jian %X We show that the vortex moduli space in non-abelian supersymmetric N=(2,2) gauge theories on the two dimensional plane with adjoint and anti-fundamental matter can be described as an holomorphic submanifold of the instanton moduli space in four dimensions. The vortex partition functions for these theories are computed via equivariant localization. We show that these coincide with the field theory limit of the topological vertex on the strip with boundary conditions corresponding to column diagrams. Moreover, we resum the field theory limit of the vertex partition functions in terms of generalized hypergeometric functions formulating their AGT dual description as interacting surface operators of simple type. Analogously we resum the topological open string amplitudes in terms of q-deformed generalized hypergeometric functions proving that they satisfy appropriate finite difference equations. %B JHEP 06(2012)178 %I SISSA %G en %U http://hdl.handle.net/1963/4134 %1 3874 %2 Physics %3 Elementary Particle Theory %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-15T08:59:30Z\\r\\nNo. of bitstreams: 1\\r\\n1102.0184v1.pdf: 250685 bytes, checksum: b0209b95cc58d31e3cd28c41cd8b0f25 (MD5) %R 10.1007/JHEP06(2012)178 %0 Journal Article %J Advances in Calculus of Variations 5 (2012) 433-483 %D 2012 %T A Viscosity-driven crack evolution %A Simone Racca %X We present a model of crack growth in brittle materials which couples dissipative effects on the crack tip and viscous effects. We consider the 2 -dimensional antiplane case with pre-assigned crack path, and firstly prove an existence result for a rate-dependent evolution problem by means of time-discretization. The next goal is to describe the rate-independent evolution as limit of the rate-dependent ones when the dissipative and viscous effects vanish. The rate-independent evolution satisfies a Griffith’s criterion for the crack growth, but, in general, it does not fulfil a global minimality condition; its fracture set may exhibit jump discontinuities with respect to time. Under suitable regularity assumptions, the quasi-static crack growth is described by solving a finite-dimensional problem. %B Advances in Calculus of Variations 5 (2012) 433-483 %I SISSA %G en %U http://hdl.handle.net/1963/5130 %1 4944 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-11-29T07:47:42Z\\r\\nNo. of bitstreams: 1\\r\\n63M_Racca.pdf: 473110 bytes, checksum: f4d49c3f7e2b984e9694fbd66a806447 (MD5) %R 10.1515/acv-2011-0012 %0 Journal Article %J Journal of Functional Analysis 262 (2012) 409-450 %D 2012 %T Weighted barycentric sets and singular Liouville equations on compact surfaces %A Alessandro Carlotto %A Andrea Malchiodi %X Given a closed two dimensional manifold, we prove a general existence result\\r\\nfor a class of elliptic PDEs with exponential nonlinearities and negative Dirac\\r\\ndeltas on the right-hand side, extending a theory recently obtained for the\\r\\nregular case. This is done by global methods: since the associated Euler\\r\\nfunctional is in general unbounded from below, we need to define a new model\\r\\nspace, generalizing the so-called space of formal barycenters and\\r\\ncharacterizing (up to homotopy equivalence) its very low sublevels. As a\\r\\nresult, the analytic problem is reduced to a topological one concerning the\\r\\ncontractibility of this model space. To this aim, we prove a new functional\\r\\ninequality in the spirit of [16] and then we employ a min-max scheme based on a cone-style construction, jointly with the blow-up analysis given in [5] (after\\r\\n[6] and [8]). This study is motivated by abelian Chern- Simons theory in\\r\\nself-dual regime, or from the problem of prescribing the Gaussian curvature in\\r\\npresence of conical singularities (hence generalizing a problem raised by\\r\\nKazdan and Warner in [26]). %B Journal of Functional Analysis 262 (2012) 409-450 %I Elsevier %G en %U http://hdl.handle.net/1963/5218 %1 5040 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-01-10T11:49:50Z\\nNo. of bitstreams: 1\\n1105.2363v2.pdf: 793763 bytes, checksum: 4996db876d03946c03fa0d4766801974 (MD5) %R 10.1016/j.jfa.2011.09.012 %0 Journal Article %J JHEP 02(2012)031 %D 2012 %T Wild quiver gauge theories %A Giulio Bonelli %A Kazunobu Maruyoshi %A Alessandro Tanzini %X We study N=2 supersymmetric SU(2) gauge theories coupled to non-Lagrangian superconformal field theories induced by compactifying the six dimensional A_1 (2,0) theory on Riemann surfaces with irregular punctures. These are naturally associated to Hitchin systems with wild ramification whose spectral curves provide the relevant Seiberg-Witten geometries. We propose that the prepotential of these gauge theories on the Omega-background can be obtained from the corresponding irregular conformal blocks on the Riemann surfaces via a generalization of the coherent state construction to the case of higher order singularities. %B JHEP 02(2012)031 %I SISSA %G en %U http://hdl.handle.net/1963/5184 %1 4999 %2 Physics %3 Elementary Particle Theory %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-12-12T14:57:36Z\\r\\nNo. of bitstreams: 1\\r\\n1112.1691v1.pdf: 374306 bytes, checksum: d108d1f4f381124a4ff917b4c621f359 (MD5) %R 10.1007/JHEP02(2012)031 %0 Journal Article %J IET systems biology. 2011 Jul; 5(4):269-79 %D 2011 %T Adaptation as a genome-wide autoregulatory principle in the stress response of yeast. %A F Eduati %A B Di Camillo %A G Toffolo %A Claudio Altafini %A Giovanna De Palo %A Mattia Zampieri %X The gene expression response of yeast to various types of stresses/perturbations shows a common functional and dynamical pattern for the vast majority of genes, characterised by a quick transient peak (affecting primarily short genes) followed by a return to the pre-stimulus level. Kinetically, this process of adaptation following the transient excursion can be modelled using a genome-wide autoregulatory mechanism by means of which yeast aims at maintaining a preferential concentration in its mRNA levels. The resulting feedback system explains well the different time constants observable in the transient response, while being in agreement with all the known experimental dynamical features. For example, it suggests that a very rapid transient can be induced also by a slowly varying concentration of the gene products. %B IET systems biology. 2011 Jul; 5(4):269-79 %I The Institution of Engineering and Technology %G en %U http://hdl.handle.net/1963/5106 %1 4922 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-11-25T13:05:49Z\\r\\nNo. of bitstreams: 1\\r\\nDePaEdal10.pdf: 2390366 bytes, checksum: f6550b1052efeb53942e47cae9632899 (MD5) %R 10.1049/iet-syb.2009.0050 %0 Journal Article %J J.Phys.A: Math.Theor. 44 (2011) 215203 %D 2011 %T An asymptotic reduction of a Painlevé VI equation to a Painlevé III %A Davide Guzzetti %X When the independent variable is close to a critical point, it is shown that\\r\\nPVI can be asymptotically reduced to PIII. In this way, it is possible to\\r\\ncompute the leading term of the critical behaviors of PVI transcendents\\r\\nstarting from the behaviors of PIII transcendents. %B J.Phys.A: Math.Theor. 44 (2011) 215203 %I IOP Publishing %G en %U http://hdl.handle.net/1963/5124 %1 4940 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-11-28T15:06:23Z\\nNo. of bitstreams: 1\\n1101.4705v1.pdf: 150593 bytes, checksum: 32af4569fb34ae6257486f096be0142b (MD5) %R 10.1088/1751-8113/44/21/215203 %0 Journal Article %J Proc. Amer. Math. Soc. 139 (2011), 1023-1032 %D 2011 %T Axial symmetry of some steady state solutions to nonlinear Schrödinger equations %A Changfeng Gui %A Andrea Malchiodi %A Haoyuan Xu %A Paul Yang %K Nonlinear Schrödinger equation %X In this note, we show the axial symmetry of steady state solutions of nonlinear Schrodinger equations when the exponent of the nonlinearity is between the critical Sobolev exponent of n dimensional space and n - 1 dimensional space. %B Proc. Amer. Math. Soc. 139 (2011), 1023-1032 %I American Mathematical Society %G en_US %U http://hdl.handle.net/1963/4100 %1 304 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-11-10T10:42:02Z\\r\\nNo. of bitstreams: 1\\r\\nGui_Malchiodi_75M.pdf: 196044 bytes, checksum: ed4d2f1be79209d4b3e7d428564d043a (MD5) %R 10.1090/S0002-9939-2010-10638-X %0 Journal Article %D 2011 %T Bishop and Laplacian Comparison Theorems on Three Dimensional Contact Subriemannian Manifolds with Symmetry %A Andrei Agrachev %A Paul W. Lee %X We prove a Bishop volume comparison theorem and a Laplacian comparison\r\ntheorem for three dimensional contact subriemannian manifolds with symmetry. %I SISSA %G en %U http://hdl.handle.net/1963/6508 %1 6455 %2 Mathematics %4 1 %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-02-27T15:12:11Z\nNo. of bitstreams: 1\n1105.2206v1.pdf: 252509 bytes, checksum: c5f4299fedd5f685c7b283c5a4ea995d (MD5) %0 Journal Article %J Communications in Mathematical Physics %D 2011 %T Branching of Cantor Manifolds of Elliptic Tori and Applications to PDEs %A Massimiliano Berti %A Luca Biasco %X We consider infinite dimensional Hamiltonian systems. We prove the existence of "Cantor manifolds" of elliptic tori-of any finite higher dimension-accumulating on a given elliptic KAM torus. Then, close to an elliptic equilibrium, we show the existence of Cantor manifolds of elliptic tori which are "branching" points of other Cantor manifolds of higher dimensional tori. We also answer to a conjecture of Bourgain, proving the existence of invariant elliptic tori with tangential frequency along a pre-assigned direction. The proofs are based on an improved KAM theorem. Its main advantages are an explicit characterization of the Cantor set of parameters and weaker smallness conditions on the perturbation. We apply these results to the nonlinear wave equation. © 2011 Springer-Verlag. %B Communications in Mathematical Physics %V 305 %P 741-796 %G eng %R 10.1007/s00220-011-1264-3 %0 Journal Article %J Comptes Rendus Mathematique 349 (2011) 161-166 %D 2011 %T A class of existence results for the singular Liouville equation %A Alessandro Carlotto %A Andrea Malchiodi %X We consider a class of elliptic PDEs on closed surfaces with exponential nonlinearities and Dirac deltas on the right-hand side. The study arises from abelian Chern–Simons theory in self-dual regime, or from the problem of prescribing the Gaussian curvature in presence of conical singularities. A general existence result is proved using global variational methods: the analytic problem is reduced to a topological problem concerning the contractibility of a model space, the so-called space of formal barycenters, characterizing the very low sublevels of a suitable functional. %B Comptes Rendus Mathematique 349 (2011) 161-166 %I Elsevier %G en %U http://hdl.handle.net/1963/5793 %1 5648 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-05-07T07:37:16Z\\nNo. of bitstreams: 0 %R 10.1016/j.crma.2010.12.016 %0 Report %D 2011 %T Compactness by maximality %A Sandro Zagatti %X We derive a compactness property in the Sobolev space $W^{1,1}(\O)$ in order to study the Dirichlet problem for the eikonal equation \begin{displaymath} \begin{cases} \ha |\n u(x)|^2 - a(x) = 0 & \ \textrm{in} \ \O\cr u(x)=\varphi(x) & \ \textrm{on} \ \partial \O, \end{cases} \end{displaymath} without continuity assumptions on the map $a$. %G en %U http://preprints.sissa.it/handle/1963/35317 %1 35626 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2018-05-24T07:53:14Z No. of bitstreams: 0 %0 Journal Article %J Proceedings of the National Academy of Sciences of the United States of America. Volume 108, Issue 52, 27 December 2011, Pages 20953-20958 %D 2011 %T Computing global structural balance in large-scale signed social networks. %A Giuseppe Facchetti %A Giovanni Iacono %A Claudio Altafini %K Combinatorial optimization %X Structural balance theory affirms that signed social networks (i.e., graphs whose signed edges represent friendly/hostile interactions among individuals) tend to be organized so as to avoid conflictual situations, corresponding to cycles of negative parity. Using an algorithm for ground-state calculation in large-scale Ising spin glasses, in this paper we compute the global level of balance of very large online social networks and verify that currently available networks are indeed extremely balanced. This property is explainable in terms of the high degree of skewness of the sign distributions on the nodes of the graph. In particular, individuals linked by a large majority of negative edges create mostly \\\"apparent disorder,\\\" rather than true \\\"frustration.\\\" %B Proceedings of the National Academy of Sciences of the United States of America. Volume 108, Issue 52, 27 December 2011, Pages 20953-20958 %I National Academy of Sciences %G en %U http://hdl.handle.net/1963/6426 %1 6362 %2 Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-01-25T12:27:12Z\\r\\nNo. of bitstreams: 1\\r\\npnas.1109521108-1.pdf: 1293098 bytes, checksum: 288a1ce2e9407b58249c5ea58a06f31b (MD5) %R 10.1073/pnas.1109521108 %0 Journal Article %J Le Matematiche (Catania), volume 66, Issue no.2, (2011), pages : 153-187 %D 2011 %T Cones of divisors of blow-ups of projective spaces %A Alessio Lo Giudice %A Salvatore Cacciola %A M. Donten-Bury %A O. Dumitrescu %A J. Park %K Mori dream space %X We investigate Mori dream spaces obtained by blowing-up the n-dimensional complex projective space at n+1, n+2 or n+3 points in very general position. Using toric techniques we study the movable cone of the blow-up of Pn at n+1 points, its decomposition into nef chambers and the action of theWeyl group on the set of chambers. Moreover, using different methods, we explicitly write down the equations of the movable cone also for Pn blown-up at n+2 points. %B Le Matematiche (Catania), volume 66, Issue no.2, (2011), pages : 153-187 %I Università degli Studi di Catania. Dipartimento di matematica %G en %U http://hdl.handle.net/1963/6613 %1 6462 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Alessio Lo Giudice (logiudic@sissa.it) on 2013-03-01T08:45:50Z No. of bitstreams: 1 CONES OF DIVISORS OF BLOW-UPS OF PROJECTIVE SPACES: 409758 bytes, checksum: 15d01ca131c41cf5f244bb4621177e36 (MD5) %R 10.4418/2011.66.2.13 %0 Journal Article %J Le Matematiche 66 (2011) 153-187 %D 2011 %T Cones of divisors of blow-ups of projective spaces %A Alessio Lo Giudice %A Salvatore Cacciola %A Maria Donten-Bury %A Olivia Dumitrescu %A Jinhyung Park %X We investigate Mori dream spaces obtained by blowing-up the n-dimensional complex projective space at n + 1, n + 2 or n + 3 points in very general position. Using toric techniques we study the movable cone of the blow-up of Pn at n + 1 points, its decomposition into nef chambers and the action of the Weyl group on the set of chambers. Moreover, using different methods, we explicitly write down the equations of the movable\\r\\ncone also for Pn blown-up at n + 2 points. %B Le Matematiche 66 (2011) 153-187 %I Universita\\\' di Catania, Dipartimento di Matematica e Informatica %G en %U http://hdl.handle.net/1963/5787 %1 5640 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-05-03T14:08:40Z\\nNo. of bitstreams: 1\\n903-3339-1-PB.pdf: 409758 bytes, checksum: 15d01ca131c41cf5f244bb4621177e36 (MD5) %R 10.4418/2011.66.2.13 %0 Journal Article %J Le Matematiche 66 (2011) 137-151 %D 2011 %T Covered by lines and Conic connected varieties %A Simone Marchesi %A Alex Massarenti %A Saeed Tafazolian %X We study some properties of an embedded variety covered by lines and give a\\r\\nnumerical criterion ensuring the existence of a singular conic through two of\\r\\nits general points. We show that our criterion is sharp. Conic-connected,\\r\\ncovered by lines, QEL, LQEL, prime Fano, defective, and dual defective\\r\\nvarieties are closely related. We study some relations between the above\\r\\nmentioned classes of objects using celebrated results by Ein and Zak. %B Le Matematiche 66 (2011) 137-151 %I Universita\\\' di Catania, Dipartimento di Matematica e Informatica %G en %U http://hdl.handle.net/1963/5788 %1 5641 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-05-03T14:43:36Z\\nNo. of bitstreams: 2\\n1105.5918v2.pdf: 279 bytes, checksum: a3b0f104eb894295409bae95af5b2e16 (MD5)\\n844-3335-1-PB.pdf: 186181 bytes, checksum: b32fc90e8bb7277d82a3c3705174e89a (MD5) %R 10.4418/2011.66.2.12 %0 Journal Article %J Discrete and Continuous Dynamical Systems - Series A 31 (2011) 1219-1231 %D 2011 %T Crack growth with non-interpenetration : a simplified proof for the pure Neumann problem %A Gianni Dal Maso %A Giuliano Lazzaroni %X We present a recent existence result concerning the quasi-static evolution of cracks in hyperelastic brittle materials, in the frame-work of finite elasticity with non-interpenetration. In particular, here we consider the problem where no Dirichlet conditions are imposed, the boundary is traction-free, and the body is subject only to time-dependent volume forces. This allows us to present the main ideas of the proof in a simpler way, avoiding some of the technicalities needed in the general case, studied in. %B Discrete and Continuous Dynamical Systems - Series A 31 (2011) 1219-1231 %I American Institute of Mathematical Sciences %G en_US %U http://hdl.handle.net/1963/3801 %1 526 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-11-27T10:24:55Z\\r\\nNo. of bitstreams: 1\\r\\nDM-Laz-proc-pre.pdf: 195002 bytes, checksum: 44e408b134f19e4d31e77b3e0762cd73 (MD5) %R 10.3934/dcds.2011.31.1219 %0 Journal Article %J This article will be published in 2011 in the \"Nagoya Mathematical Journal\" Volume 201, March 2011, Pages 1-22, under the title \"Computing certain Gromov-Witten invariants of the crepant resolution of P{double-strock}(1, 3, 4, 4) %D 2011 %T Crepant resolutions of weighted projective spaces and quantum deformations %A Samuel Boissiere %A Etienne Mann %A Fabio Perroni %X We compare the Chen-Ruan cohomology ring of the weighted projective spaces\r\n$\\IP(1,3,4,4)$ and $\\IP(1,...,1,n)$ with the cohomology ring of their crepant\r\nresolutions. In both cases, we prove that the Chen-Ruan cohomology ring is\r\nisomorphic to the quantum corrected cohomology ring of the crepant resolution\r\nafter suitable evaluation of the quantum parameters. For this, we prove a\r\nformula for the Gromov-Witten invariants of the resolution of a transversal\r\n${\\rm A}_3$ singularity. %B This article will be published in 2011 in the \"Nagoya Mathematical Journal\" Volume 201, March 2011, Pages 1-22, under the title \"Computing certain Gromov-Witten invariants of the crepant resolution of P{double-strock}(1, 3, 4, 4) %I SISSA %G en %U http://hdl.handle.net/1963/6514 %1 6463 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Fabio Perroni (perroni@sissa.it) on 2013-02-28T17:54:00Z\nNo. of bitstreams: 1\nmath_0610617v2.pdf: 309225 bytes, checksum: 1488b79e5765bdffd4353bd8e04ffa8e (MD5) %0 Report %D 2011 %T Critical points of the Moser-Trudinger functional %A Francesca De Marchis %A Andrea Malchiodi %A Luca Martinazzi %K Moser-Trudinger inequality %I SISSA %G en %U http://hdl.handle.net/1963/4592 %1 4353 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-10-07T11:40:39Z\\nNo. of bitstreams: 1\\n46M_Malchiodi.pdf: 234581 bytes, checksum: 365098bf21692bfa547056b200acb4c6 (MD5) %0 Journal Article %J PNAS 108 (2011) 13978 %D 2011 %T Cytoskeletal actin networks in motile cells are critically self-organized systems synchronized by mechanical interactions %A Luca Cardamone %A Alessandro Laio %A Rajesh Shahapure %A Antonio DeSimone %B PNAS 108 (2011) 13978 %I National Academy of Sciences %G en %U http://hdl.handle.net/1963/4358 %1 4066 %2 Physics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-28T06:31:24Z\\nNo. of bitstreams: 0 %R 10.1073/pnas.1100549108 %0 Report %D 2011 %T D-branes, surface operators, and ADHM quiver representations %A Ugo Bruzzo %A Duiliu-Emanuel Diaconescu %A M. Yardim %A G. Pan %A Y. Zhang %A Chuang Wu-yen %X A supersymmetric quantum mechanical model is constructed for BPS states bound to surface operators in five dimensional SU(r) gauge theories using D-brane engineering. This model represents the effective action of a certain D2-brane configuration, and is naturally obtained by dimensional reduction of a quiver $(0,2)$ gauged linear sigma model. In a special stability chamber, the resulting moduli space of quiver representations is shown to be smooth and isomorphic to a moduli space of framed quotients on the projective plane. A precise conjecture relating a K-theoretic partition function of this moduli space to refined open string invariants of toric lagrangian branes is formulated for conifold and local P^1 x P^1 geometries. %I SISSA %G en %U http://hdl.handle.net/1963/4133 %1 3873 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-15T08:27:03Z\\r\\nNo. of bitstreams: 1\\r\\n1012.1826v2.pdf: 536824 bytes, checksum: 38cd256a97e7244dc3eaac8073827cc2 (MD5) %0 Journal Article %J Communications on Pure and Applied Analysis 10 (2011) 1549-1566 %D 2011 %T A Decomposition Theorem for BV functions %A Stefano Bianchini %A Daniela Tonon %B Communications on Pure and Applied Analysis 10 (2011) 1549-1566 %I American Institute of Mathematical Sciences %G en_US %U http://hdl.handle.net/1963/3608 %1 693 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-04-07T15:11:02Z\\r\\nNo. of bitstreams: 1\\r\\narticoloBV-preprint.pdf: 278021 bytes, checksum: db1d8f4c30a60313b69e105977010165 (MD5) %0 Journal Article %J Journal of Differential Equations %D 2011 %T Degenerate KAM theory for partial differential equations %A Bambusi, D. %A Massimiliano Berti %A Magistrelli, E. %X This paper deals with degenerate KAM theory for lower dimensional elliptic tori of infinite dimensional Hamiltonian systems, depending on one parameter only. We assume that the linear frequencies are analytic functions of the parameter, satisfy a weak non-degeneracy condition of Rüssmann type and an asymptotic behavior. An application to nonlinear wave equations is given. © 2010 Elsevier Inc. %B Journal of Differential Equations %V 250 %P 3379-3397 %G eng %R 10.1016/j.jde.2010.11.002 %0 Thesis %D 2011 %T Dimensional Reduction and Approximation of Measures and Weakly Differentiable Homeomorphisms %A Sara Daneri %X This thesis is devoted to the study of two different problems: the properties of the disintegration of the Lebesgue measure on the faces of a convex function and the existence of smooth approximations of bi-Lipschitz orientation-preserving homeomorphisms in the plane. %I SISSA %G en %U http://hdl.handle.net/1963/5348 %1 5178 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-02-02T16:17:40Z\\nNo. of bitstreams: 1\\nTesiPhDDaneriFinal.pdf: 1042283 bytes, checksum: be3ac0827af99c78eafc9395b4670544 (MD5) %0 Journal Article %J Journal de Mathematiques Pures et Appliquees 95 (2011) 565-584 %D 2011 %T Energy release rate and stress intensity factor in antiplane elasticity %A Giuliano Lazzaroni %A Rodica Toader %X In the setting of antiplane linearized elasticity, we show the existence of the stress intensity factor and its relation with the energy release rate when the crack path is a C1,1 curve. Finally, we show that the energy release rate is continuous with respect to the Hausdorff convergence in a class of admissible cracks. %B Journal de Mathematiques Pures et Appliquees 95 (2011) 565-584 %I Elsevier %G en_US %U http://hdl.handle.net/1963/3780 %1 546 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-11-17T11:50:32Z\\r\\nNo. of bitstreams: 2\\r\\nLazzaroni_67M_2009.pdf: 259616 bytes, checksum: 3c3adef52607bc6238c11a84904a9fb9 (MD5)\\r\\nLazzaroni_67M_2009: 259616 bytes, checksum: 3c3adef52607bc6238c11a84904a9fb9 (MD5) %R 10.1016/j.matpur.2011.01.001 %0 Journal Article %J Discrete and Continuous Dynamical Systems - Series A 31 (2011) 1017-1021 %D 2011 %T Ennio De Giorgi and Γ-convergence %A Gianni Dal Maso %X Γ-convergence was introduced by Ennio De Giorgi in a series of papers published between 1975 and 1983. In the same years he developed many applications of this tool to a great variety of asymptotic problems in the calculus of variations and in the theory of partial differential equations. %B Discrete and Continuous Dynamical Systems - Series A 31 (2011) 1017-1021 %I American Institute of Mathematical Sciences %G en %U http://hdl.handle.net/1963/5308 %1 5138 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-01-31T12:04:34Z\\nNo. of bitstreams: 0 %R 10.3934/dcds.2011.31.1017 %0 Journal Article %J Communications in Partial Differential Equations 36 (2011) 777-796 %D 2011 %T An Estimate on the Flow Generated by Monotone Operators %A Stefano Bianchini %A Matteo Gloyer %B Communications in Partial Differential Equations 36 (2011) 777-796 %I Taylor & Francis %G en_US %U http://hdl.handle.net/1963/3646 %1 658 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-06-10T13:06:54Z\\r\\nNo. of bitstreams: 1\\r\\n29_2009M.pdf: 209332 bytes, checksum: b30a32046e7a3c3c30436e84c03dc6d3 (MD5) %R 10.1080/03605302.2010.534224 %0 Journal Article %J SIAM J. Math. Anal. 43 (2011) 1345-1368 %D 2011 %T An Existence and Uniqueness Result for the Motion of Self-Propelled Microswimmers %A Gianni Dal Maso %A Antonio DeSimone %A Marco Morandotti %X We present an analytical framework to study the motion of micro-swimmers in a viscous fluid. Our main result is that, under very mild regularity assumptions, the change of shape determines uniquely the motion of the swimmer. We assume that the Reynolds number is very small, so that the velocity field of the surrounding, infinite fluid is governed by the Stokes system and all inertial effects can be neglected. Moreover, we enforce the self propulsion constraint (no external forces and torques). Therefore, Newton\\\'s equations of motion reduce to the vanishing of the viscous drag force and torque acting on the body. By exploiting an integral representation of viscous force and torque, the equations of motion can be reduced to a system of six ordinary differential equations. Variational techniques are used to prove the boundedness and measurability of its coefficients, so that classical results on ordinary differential equations can be invoked to prove existence and uniqueness of the solution. %B SIAM J. Math. Anal. 43 (2011) 1345-1368 %I Society for Industrial and Applied Mathematics %G en_US %U http://hdl.handle.net/1963/3894 %1 815 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-07-23T11:44:06Z\\r\\nNo. of bitstreams: 1\\r\\nMorandotti_44M.pdf: 217358 bytes, checksum: 4c362016bb2220e7a97805254b7fb870 (MD5) %R 10.1137/10080083X %0 Journal Article %J Rend. Lincei Mat. Appl. 22 (2011) 387-408 %D 2011 %T Existence for wave equations on domains with arbitrary growing cracks %A Gianni Dal Maso %A Cristopher J. Larsen %K Wave equation %X In this paper we formulate and study scalar wave equations on domains with arbitrary growing cracks. This includes a zero Neumann condition on the crack sets, and the only assumptions on these sets are that they have bounded surface measure and are growing in the sense of set inclusion. In particular, they may be dense, so the weak formulations must fall outside of the usual weak formulations using Sobolev spaces. We study both damped and undamped equations, showing existence and, for the damped equation, uniqueness and energy conservation. %B Rend. Lincei Mat. Appl. 22 (2011) 387-408 %I European Mathematical Society %G en %U http://hdl.handle.net/1963/4284 %1 4015 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-27T09:09:30Z\\r\\nNo. of bitstreams: 1\\r\\nDM-Lar_32_M.pdf: 223891 bytes, checksum: 7c6c66b6d21936b33ed0c21574928e24 (MD5) %R 10.4171/RLM/606 %0 Journal Article %J Advances in Calculus of Variations., to appear. %D 2011 %T Fracture and plastic models as Gamma-limits of damage models under different regimes %A Flaviana Iurlano %XWe consider a variational model for damaged elastic materials. This model depends on three small parameters, which are related to the cost of the damage, to the width of the damaged regions, and to the minimum elasticity constant attained in the damaged regions. As these parameters tend to zero, our models Gamma-converge to a model for brittle fracture, for fracture with a cohesive zone, or for perfect plasticity, depending on the asymptotic ratios of the three parameters.

%B Advances in Calculus of Variations., to appear. %I Walter de Gruyter %G en %U http://hdl.handle.net/1963/5069 %1 4883 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-11-15T11:55:02Z\\r\\nNo. of bitstreams: 1\\r\\nIurlano_59M_2011.pdf: 387080 bytes, checksum: e5aab40ae643ec056bf0adc92bcaa7c8 (MD5) %R 10.1515/acv-2011-0011 %0 Journal Article %J Continuum. Mech. Therm. 23 (2011) 257 %D 2011 %T Gamma-convergence of energies for nematic elastomers in the small strain limit %A Virginia Agostiniani %A Antonio DeSimone %K Liquid crystals %X We study two variational models recently proposed in the literature to describe the mechanical behaviour of nematic elastomers either in the fully nonlinear regime or in the framework of a geometrically linear theory. We show that, in the small strain limit, the energy functional of the first one I\\\"-converges to the relaxation of the second one, a functional for which an explicit representation formula is available. %B Continuum. Mech. Therm. 23 (2011) 257 %I Springer %G en %U http://hdl.handle.net/1963/4141 %1 3882 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-15T13:10:38Z\\nNo. of bitstreams: 1\\nAgost_DeSim07M.pdf: 348761 bytes, checksum: b9b69eb7da7ca6962e4a46e904646a6b (MD5) %R 10.1007/s00161-011-0180-2 %0 Journal Article %J J. Eur. Math. Soc. (JEMS), to appear %D 2011 %T Generalised functions of bounded deformation %A Gianni Dal Maso %K free discontinuity problems, special functions of bounded deformation, jump set, rec- tifiability, slicing, approximate differentiability %XWe introduce the space GBD of generalized functions of bounded deformation and study the structure properties of these functions: the rectifiability and the slicing properties of their jump sets, and the existence of their approximate symmetric gradients. We conclude by proving a compactness results for GBD, which leads to a compactness result for the space GSBD of generalized special functions of bounded deformation. The latter is connected to the existence of solutions to a weak formulation of some variational problems arising in fracture mechanics in the framework of linearized elasticity.

%B J. Eur. Math. Soc. (JEMS), to appear %I SISSA %G en %U http://hdl.handle.net/1963/6374 %1 6309 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Gianni Dal Maso (dalmaso@sissa.it) on 2013-01-10T18:54:48Z\\nNo. of bitstreams: 1\\nDM-11.pdf: 413971 bytes, checksum: eca2a953ba1b97755da281bca4e099e4 (MD5) %0 Journal Article %J JHEP, Volume 2011, Issue 7, 2011, Article number055 %D 2011 %T Generalized matrix models and AGT correspondence at all genera %A Giulio Bonelli %A Kazunobu Maruyoshi %A Alessandro Tanzini %A Futoshi Yagib %X We study generalized matrix models corresponding to n-point Virasoro\r\nconformal blocks on Riemann surfaces with arbitrary genus g. Upon AGT\r\ncorrespondence, these describe four dimensional N=2 SU(2)^{n+3g-3} gauge\r\ntheories with generalized quiver diagrams. We obtain the generalized matrix\r\nmodels from the perturbative evaluation of the Liouville correlation functions\r\nand verify the consistency of the description with respect to degenerations of\r\nthe Riemann surface. Moreover, we derive the Seiberg-Witten curve for the N=2\r\ngauge theory as the spectral curve of the generalized matrix model, thus\r\nproviding a check of AGT correspondence at all genera. %B JHEP, Volume 2011, Issue 7, 2011, Article number055 %I SISSA %G en %U http://hdl.handle.net/1963/6568 %1 6530 %2 Mathematics %4 1 %$ Submitted by Alessandro Tanzini (tanzini@sissa.it) on 2013-04-04T10:07:44Z\nNo. of bitstreams: 1\n1011.5417v2.pdf: 288213 bytes, checksum: 4ffb3884bb05de0280c0f8a0dc7847ab (MD5) %R 10.1007/JHEP07(2011)055 %0 Journal Article %J JHEP 07(2011)055 %D 2011 %T Generalized matrix models and AGT correspondence at all genera %A Giulio Bonelli %A Kazunobu Maruyoshi %A Alessandro Tanzini %A Futoshi Yagi %X We study generalized matrix models corresponding to n-point Virasoro conformal blocks on Riemann surfaces with arbitrary genus g. Upon AGT correspondence, these describe four dimensional N=2 SU(2)^{n+3g-3} gauge theories with generalized quiver diagrams. We obtain the generalized matrix models from the perturbative evaluation of the Liouville correlation functions and verify the consistency of the description with respect to degenerations of the Riemann surface. Moreover, we derive the Seiberg-Witten curve for the N=2 gauge theory as the spectral curve of the generalized matrix model, thus providing a check of AGT correspondence at all genera. %B JHEP 07(2011)055 %I Springer %G en_US %U http://hdl.handle.net/1963/4111 %1 293 %2 Physics %3 Elementary Particle Theory %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-12-07T10:18:07Z\\r\\nNo. of bitstreams: 1\\r\\nBonelli_82_2010EP-FM.pdf: 227879 bytes, checksum: 108af46480711a5b0126c0b39059d764 (MD5) %R 10.1007/JHEP07(2011)055 %0 Journal Article %D 2011 %T Generalized Ricci Curvature Bounds for Three Dimensional Contact Subriemannian manifolds %A Andrei Agrachev %A Paul Lee %I SISSA %G en %U http://hdl.handle.net/1963/6507 %1 6454 %2 Mathematics %4 1 %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-02-27T15:07:16Z\nNo. of bitstreams: 2\n0903.2550v3.pdf: 413981 bytes, checksum: 6f08d5002703670b5985e13d642ef755 (MD5)\n0903.2550v3.pdf: 413981 bytes, checksum: 6f08d5002703670b5985e13d642ef755 (MD5) %0 Journal Article %J Proceedings of the Steklov Institute of mathematics. vol. 273 (2011), page: 5-27 ; ISSN: 0081-5438 %D 2011 %T The geometry of Maximum Principle %A Andrei Agrachev %A Revaz Gamkrelidze %X An invariant formulation of the maximum principle in optimal control is presented, and some second-order invariants are discussed. %B Proceedings of the Steklov Institute of mathematics. vol. 273 (2011), page: 5-27 ; ISSN: 0081-5438 %G en %U http://hdl.handle.net/1963/6456 %1 6401 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-02-05T14:28:16Z\\nNo. of bitstreams: 0 %0 Journal Article %J Differential Geometry and its Applications 29 (2011) 147-153 %D 2011 %T Holomorphic Cartan geometry on manifolds with numerically effective tangent bundle %A Indranil Biswas %A Ugo Bruzzo %B Differential Geometry and its Applications 29 (2011) 147-153 %I Elsevier %G en_US %U http://hdl.handle.net/1963/3830 %1 497 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-01-26T15:20:25Z\\r\\nNo. of bitstreams: 1\\r\\nbiswas-bruzzo_2010.pdf: 181667 bytes, checksum: ac09c3a64c7a8642ae63e2b807f2da64 (MD5) %R 10.1016/j.difgeo.2011.02.001 %0 Thesis %D 2011 %T Homology invariants of quadratic maps %A Antonio Lerario %X Given a real projective algebraic set X we could hope that the equations describing it can give some information on its topology, e.g. on the number of its connected components. Unfortunately in the general case this hope is too vague and there is no direct way to extract such information from the algebraic description of X: Even the problem to decide whether X is empty or not is far from an easy visualization and requires some complicated algebraic machinery. A fi rst step observation is that as long as we are interested only in the topology of X, we can replace, using some Veronese embedding, the original ambient space with a much bigger RPn and assume that X is cut by quadratic equations. The price for this is the increase of the number of equations de ning our set; the advantage is that quadratic polynomials are easier to handle and our hope becomes more concrete... %I SISSA %G en %U http://hdl.handle.net/1963/6245 %1 6145 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-09-14T09:24:43Z\\nNo. of bitstreams: 1\\nPhd_Thesis_Lerario_Antonio.pdf: 937331 bytes, checksum: f34eea56b610434e63b6f3dd1dded09c (MD5) %] 1 Basic theory. 2 Nondegeneracy conditions. 3 Spectral sequences. 4 Complex theory. 5 Applications and examples %0 Journal Article %J Matematische Annalen 349 (2011) 75-115 %D 2011 %T Infinite-dimensional Frobenius manifolds for 2 + 1 integrable systems %A Guido Carlet %A Boris Dubrovin %A Luca Philippe Mertens %X We introduce a structure of an infinite-dimensional Frobenius manifold on a subspace in the space of pairs of functions analytic inside/outside the unit circle with simple poles at 0/infinity respectively. The dispersionless 2D Toda equations are embedded into a bigger integrable hierarchy associated with this Frobenius manifold. %B Matematische Annalen 349 (2011) 75-115 %I Springer %G en_US %U http://hdl.handle.net/1963/3584 %1 716 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-03-09T09:29:31Z\\r\\nNo. of bitstreams: 1\\r\\n0902.1245.pdf: 343930 bytes, checksum: 421342a05bb8986c1bf542d6446f5792 (MD5) %R 10.1007/s00208-010-0509-3 %0 Report %D 2011 %T Instantons on ALE spaces and Super Liouville Conformal Field Theories %A Giulio Bonelli %A Kazunobu Maruyoshi %A Alessandro Tanzini %X We provide evidence that the conformal blocks of N=1 super Liouville\\r\\nconformal field theory are described in terms of the SU(2) Nekrasov partition\\r\\nfunction on the ALE space O_{P^1}(-2). %I SISSA %G en %U http://hdl.handle.net/1963/4262 %1 3987 %2 Physics %3 Elementary Particle Theory %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-26T14:31:56Z\\nNo. of bitstreams: 1\\n1106.2505v1.pdf: 137191 bytes, checksum: 721cf25d724b7aca87a3429a0119e201 (MD5) %0 Report %D 2011 %T Instantons on ALE spaces and Super Liouville Conformal Field Theories %A Giulio Bonelli %A Kazunobu Maruyoshi %A Alessandro Tanzini %X We provide evidence that the conformal blocks of N=1 super Liouville\r\nconformal field theory are described in terms of the SU(2) Nekrasov partition\r\nfunction on the ALE space O_{P^1}(-2). %I SISSA %G en %U http://hdl.handle.net/1963/6573 %1 6526 %2 Mathematics %4 -1 %$ Submitted by Alessandro Tanzini (tanzini@sissa.it) on 2013-04-04T10:04:23Z\nNo. of bitstreams: 1\n1106.2505v1.pdf: 137191 bytes, checksum: 721cf25d724b7aca87a3429a0119e201 (MD5) %0 Journal Article %J Journal of Convex Analysis 18 (2011) 1141-1170 %D 2011 %T An Integro-Extremization Approach for Non Coercive and Evolution Hamilton-Jacobi Equations %A Sandro Zagatti %X We devote the \\\\textit{integro-extremization} method to the study of the Dirichlet problem for homogeneous Hamilton-Jacobi equations \\\\begin{displaymath} \\\\begin{cases} F(Du)=0 & \\\\quad \\\\textrm{in} \\\\quad\\\\O\\\\cr u(x)=\\\\varphi(x) & \\\\quad \\\\textrm{for} \\\\quad x\\\\in \\\\partial \\\\O, \\\\end{cases} \\\\end{displaymath} with a particular interest for non coercive hamiltonians $F$, and to the Cauchy-Dirichlet problem for the corresponding homogeneous time-dependent equations \\\\begin{displaymath} \\\\begin{cases} \\\\frac{\\\\partial u}{\\\\partial t}+ F(\\\\nabla u)=0 & \\\\quad \\\\textrm{in} \\\\quad ]0,T[\\\\times \\\\O\\\\cr u(0,x)=\\\\eta(x) & \\\\quad \\\\textrm{for} \\\\quad x\\\\in\\\\O \\\\cr u(t,x)=\\\\psi(x) & \\\\quad \\\\textrm{for} \\\\quad (t,x)\\\\in[0,T]\\\\times \\\\partial \\\\O. \\\\end{cases} \\\\end{displaymath} We prove existence and some qualitative results for viscosity and almost everywhere solutions, under suitably convexity conditions on the hamiltonian $F$, on the domain $\\\\O$ and on the boundary datum, without any growth assumptions on $F$. %B Journal of Convex Analysis 18 (2011) 1141-1170 %I Heldermann Verlag %G en %U http://hdl.handle.net/1963/5538 %1 5375 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-02-23T14:37:59Z\\nNo. of bitstreams: 0 %0 Journal Article %J Journal of Differential Equations 250 (2011) 1788-1827 %D 2011 %T Invariant manifolds for a singular ordinary differential equation %A Stefano Bianchini %A Laura Spinolo %B Journal of Differential Equations 250 (2011) 1788-1827 %I Elsevier %G en_US %U http://hdl.handle.net/1963/2554 %1 1565 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-01-15T10:35:53Z\\r\\nNo. of bitstreams: 1\\r\\nSissa0408M.pdf: 296248 bytes, checksum: 7563bf5d03a78a0e2c2c606a9b609827 (MD5) %R 10.1016/j.jde.2010.11.010 %0 Thesis %D 2011 %T Invariants, volumes and heat kernels in sub-Riemannian geometry %A Davide Barilari %K Sub-Riemannian geometry %X Sub-Riemannian geometry can be seen as a generalization of Riemannian geometry under non-holonomic constraints. From the theoretical point of view, sub-Riemannian geometry is the geometry underlying the theory of hypoelliptic operators (see [32, 57, 70, 92] and references therein) and many problems of geometric measure theory (see for instance [18, 79]). In applications it appears in the study of many mechanical problems (robotics, cars with trailers, etc.) and recently in modern elds of research such as mathematical models of human behaviour, quantum control or motion of self-propulsed micro-organism (see for instance [15, 29, 34])\\r\\nVery recently, it appeared in the eld of cognitive neuroscience to model the\\r\\nfunctional architecture of the area V1 of the primary visual cortex, as proposed by Petitot in [87, 86], and then by Citti and Sarti in [51]. In this context, the sub-Riemannian heat equation has been used as basis to new applications in image reconstruction (see [35]). %I SISSA %G en %U http://hdl.handle.net/1963/6124 %1 6005 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-08-08T07:49:33Z\\nNo. of bitstreams: 1\\nPhD_Thesis_Barilari.pdf: 924464 bytes, checksum: dd34c4627062993f1d72d4c7eff914e6 (MD5) %0 Journal Article %J Communication in Partial Differential Equations 36 (2011) 2062-2102 %D 2011 %T Large Time Existence for Thin Vibrating Plates %A Helmut Abels %A Maria Giovanna Mora %A Stefan Mueller %X We construct strong solutions for a nonlinear wave equation for a thin vibrating plate described by nonlinear elastodynamics. For sufficiently small thickness we obtain existence of strong solutions for large\\r\\ntimes under appropriate scaling of the initial values such that the limit system as h --> 0 is either the nonlinear von Karman plate equation or the linear fourth order Germain-Lagrange equation. In the case of the\\r\\nlinear Germain-Lagrange equation we even obtain a convergence rate of the three-dimensional solution to the solution of the two-dimensional linear plate equation. %B Communication in Partial Differential Equations 36 (2011) 2062-2102 %I Taylor & Francis %G en_US %U http://hdl.handle.net/1963/3755 %1 562 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-09-15T09:12:35Z\\r\\nNo. of bitstreams: 1\\r\\nLongTimeExistence.pdf: 331066 bytes, checksum: eba3dcbc86ddcd7b92e10fddca5964c4 (MD5) %R 10.1080/03605302.2011.618209 %0 Journal Article %J Functional Analysis and Its Applications. Volume 45, Issue 4, December 2011, Pages 278-290 %D 2011 %T Linearly degenerate Hamiltonian PDEs and a new class of solutions to the WDVV associativity equations %A Boris Dubrovin %A M.V. Pavlov %A Sergei A. Zykov %K Frobenius manifold %X We define a new class of solutions to the WDVV associativity equations. This class is determined by the property that one of the commuting PDEs associated with such a WDVV solution is linearly degenerate. We reduce the problem of classifying such solutions of the WDVV equations to the particular case of the so-called algebraic Riccati equation and, in this way, arrive at a complete classification of irreducible solutions. %B Functional Analysis and Its Applications. Volume 45, Issue 4, December 2011, Pages 278-290 %I Springer %G en %U http://hdl.handle.net/1963/6430 %1 6367 %2 Mathematics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2013-01-29T11:15:30Z No. of bitstreams: 1 dubrovin_linearly.pdf: 298813 bytes, checksum: 568feaa543b4082cc8e8fab4643dce71 (MD5) %R 10.1007/s10688-011-0030-9 %0 Report %D 2011 %T The Liouville side of the Vortex %A Giulio Bonelli %A Alessandro Tanzini %A Jian Zhao %X We analyze conformal blocks with multiple (semi-)degenerate field insertions\r\nin Liouville/Toda conformal field theories an show that their vector space is\r\nfully reproduced by the four-dimensional limit of open topological string\r\namplitudes on the strip with generic boundary conditions associated to a\r\nsuitable quiver gauge theory. As a byproduct we identify the non-abelian vortex\r\npartition function with a specific fusion channel of degenerate conformal\r\nblocks. %I SISSA %G en %U http://hdl.handle.net/1963/6574 %1 6525 %2 Mathematics %4 -1 %$ Submitted by Alessandro Tanzini (tanzini@sissa.it) on 2013-04-04T10:03:39Z\nNo. of bitstreams: 1\n1107.2787v1.pdf: 990433 bytes, checksum: 1dc28192f585097bc1e32987afd97aa7 (MD5) %0 Journal Article %J JHEP 09(2011)096 %D 2011 %T The Liouville side of the vortex %A Giulio Bonelli %A Alessandro Tanzini %A Jian Zhao %X We analyze conformal blocks with multiple (semi-)degenerate field insertions in Liouville/Toda conformal field theories an show that their vector space is fully reproduced by the four-dimensional limit of open topological string amplitudes on the strip with generic boundary conditions associated to a suitable quiver gauge theory. As a byproduct we identify the non-abelian vortex partition function with a specific fusion channel of degenerate conformal blocks. %B JHEP 09(2011)096 %I SISSA %G en %U http://hdl.handle.net/1963/4304 %1 4019 %2 Physics %3 Elementary Particle Theory %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-27T09:53:04Z\\r\\nNo. of bitstreams: 1\\r\\n1107.2787v1.pdf: 990433 bytes, checksum: 1dc28192f585097bc1e32987afd97aa7 (MD5) %R 10.1007/JHEP09(2011)096 %0 Report %D 2011 %T On the Lp-differentiability of certain classes of functions %A Giovanni Alberti %A Stefano Bianchini %A Gianluca Crippa %I SISSA %G en %U http://hdl.handle.net/1963/4658 %1 4423 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-10-10T12:04:05Z\\nNo. of bitstreams: 1\\nAlberti_Bianchini_50_M.pdf: 253000 bytes, checksum: 06381747f80814ced325966adefdec91 (MD5) %0 Journal Article %J Archive for Rational Mechanics and Analysis 200 (2011) 1023-1050 %D 2011 %T The matching property of infinitesimal isometries on elliptic surfaces and elasticity on thin shells %A Marta Lewicka %A Maria Giovanna Mora %A Mohammad Reza Pakzad %X Using the notion of Γ-convergence, we discuss the limiting behavior of the three-dimensional nonlinear elastic energy for thin elliptic shells, as their thickness h converges to zero, under the assumption that the elastic energy of deformations scales like h β with 2 < β < 4. We establish that, for the given scaling regime, the limiting theory reduces to linear pure bending. Two major ingredients of the proofs are the density of smooth infinitesimal isometries in the space of W 2,2 first order infinitesimal isometries, and a result on matching smooth infinitesimal isometries with exact isometric immersions on smooth elliptic surfaces. %B Archive for Rational Mechanics and Analysis 200 (2011) 1023-1050 %I Springer %G en_US %U http://hdl.handle.net/1963/3392 %1 940 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-12-05T19:03:58Z\\r\\nNo. of bitstreams: 1\\r\\nlemopa_convex4.pdf: 284015 bytes, checksum: 201392cdf06b00dfe1026dba836582b8 (MD5) %R 10.1007/s00205-010-0387-6 %0 Journal Article %J Continuum Mechanics and Thermodynamics 23 (2011) 453-471 %D 2011 %T Metastable equilibria of capillary drops on solid surfaces: a phase field approach %A Livio Fedeli %A Alessandro Turco %A Antonio DeSimone %X We discuss a phase field model for the numerical simulation of metastable equilibria of capillary drops resting on rough solid surfaces and for the description of contact angle hysteresis phenomena in wetting. The model is able to reproduce observed transitions of drops on micropillars from Cassie–Baxter to Wenzel states. When supplemented with a dissipation potential which describes energy losses due to frictional forces resisting the motion of the contact line, the model can describe metastable states such as drops in equilibrium on vertical glass plates. The reliability of the model is assessed by a detailed comparison of its predictions with experimental data on the maximal size of water drops that can stick on vertical glass plates which have undergone different surface treatments. %B Continuum Mechanics and Thermodynamics 23 (2011) 453-471 %I Springer %G en %U http://hdl.handle.net/1963/5795 %1 5651 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-05-07T07:58:01Z\\nNo. of bitstreams: 0 %R 10.1007/s00161-011-0189-6 %0 Journal Article %J {MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES} %D 2011 %T A MODEL FOR CRACK PROPAGATION BASED ON VISCOUS APPROXIMATION %A Giuliano Lazzaroni %A Toader, Rodica %K Brittle fracture %K Crack propagation %K energy derivative %K energy release rate %K free-discontinuity problems %K Griffith's criterion %K local minimizers %K stress intensity factor} %K vanishing viscosity %K {Variational models %X{In the setting of antiplane linearized elasticity, we show the existence of quasistatic evolutions of cracks in brittle materials by using a vanishing viscosity approach, thus taking into account local minimization. The main feature of our model is that the path followed by the crack need not be prescribed a priori: indeed, it is found as the limit (in the sense of Hausdorff convergence) of curves obtained by an incremental procedure. The result is based on a continuity property for the energy release rate in a suitable class of admissible cracks.}

%B {MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES} %I {WORLD SCIENTIFIC PUBL CO PTE LTD} %C {5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE} %V {21} %P {2019-2047} %8 {OCT} %G eng %9 {Article} %R {10.1142/S0218202511005647} %0 Journal Article %J Doc. Math. 16 (2011) 399-410 %D 2011 %T Moduli of framed sheaves on projective surfaces %A Ugo Bruzzo %A Dimitri Markushevich %X We show that there exists a fine moduli space for torsion-free sheaves on a\\r\\nprojective surface, which have a \\\"good framing\\\" on a big and nef divisor. This\\r\\nmoduli space is a quasi-projective scheme. This is accomplished by showing that such framed sheaves may be considered as stable pairs in the sense of\\r\\nHuybrechts and Lehn. We characterize the obstruction to the smoothness of the moduli space, and discuss some examples on rational surfaces. %B Doc. Math. 16 (2011) 399-410 %I Documenta Mathematica %G en %U http://hdl.handle.net/1963/5126 %1 4942 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-11-28T15:59:58Z\\nNo. of bitstreams: 1\\n0906.1436v2.pdf: 285229 bytes, checksum: 6451a4aeb6a764184842f8515fec4930 (MD5) %0 Journal Article %J Sports Engineering %D 2011 %T Multi-physics modelling and sensitivity analysis of olympic rowing boat dynamics %A Andrea Mola %A Mehdi Ghommem %A Muhammad Hajj %B Sports Engineering %I Springer Nature %V 14 %P 85–94 %8 nov %G eng %U https://doi.org/10.1007/s12283-011-0075-2 %R 10.1007/s12283-011-0075-2 %0 Journal Article %J Geometric and Functional Analysis 21 (2011) 1196-1217 %D 2011 %T New improved Moser-Trudinger inequalities and singular Liouville equations on compact surfaces %A Andrea Malchiodi %A David Ruiz %X We consider a singular Liouville equation on a compact surface, arising from the study of Chern-Simons vortices in a self dual regime. Using new improved versions of the Moser-Trudinger inequalities (whose main feature is to be scaling invariant) and a variational scheme, we prove new existence results. %B Geometric and Functional Analysis 21 (2011) 1196-1217 %I Springer %G en_US %U http://hdl.handle.net/1963/4099 %1 305 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-11-10T10:27:54Z\\r\\nNo. of bitstreams: 1\\r\\nMalchiodi-Ruiz-74M.pdf: 192985 bytes, checksum: 61acb10ab3cde055824228920d16987a (MD5) %R 10.1007/s00039-011-0134-7 %0 Report %D 2011 %T Nonlinear thin-walled beams with a rectangular cross-section - Part II %A Lorenzo Freddi %A Maria Giovanna Mora %A Roberto Paroni %K Thin-walled cross-section beams %X In this paper we report the second part of our results concerning the rigorous derivation of a hierarchy of one-dimensional models for thin-walled beams with rectangular cross-section.. %I SISSA %G en %U http://hdl.handle.net/1963/4169 %1 3891 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-20T13:52:25Z\\nNo. of bitstreams: 1\\nFreddi_Mora_14_M.pdf: 427788 bytes, checksum: e3682dceada2647cc7dee99102979180 (MD5) %0 Journal Article %J Duke Mathematical Journal %D 2011 %T Nonlinear wave and Schrödinger equations on compact Lie groups and homogeneous spaces %A Massimiliano Berti %A Michela Procesi %X We develop linear and nonlinear harmonic analysis on compact Lie groups and homogeneous spaces relevant for the theory of evolutionary Hamiltonian PDEs. A basic tool is the theory of the highest weight for irreducible representations of compact Lie groups. This theory provides an accurate description of the eigenvalues of the Laplace-Beltrami operator as well as the multiplication rules of its eigenfunctions. As an application, we prove the existence of Cantor families of small amplitude time-periodic solutions for wave and Schr¨odinger equations with differentiable nonlinearities. We apply an abstract Nash-Moser implicit function theorem to overcome the small divisors problem produced by the degenerate eigenvalues of the Laplace operator. We provide a new algebraic framework to prove the key tame estimates for the inverse linearized operators on Banach scales of Sobolev functions. %B Duke Mathematical Journal %V 159 %8 2011 %G eng %N 3 %& 479 %R 10.1215/00127094-1433403 %0 Journal Article %J J. Phys. A 44 (2011) 315302 %D 2011 %T On the number of eigenvalues of a model operator related to a system of three particles on lattices %A Gianfausto Dell'Antonio %A Zahriddin I. Muminov %A Y.M. Shermatova %B J. Phys. A 44 (2011) 315302 %I IOP Publishing %G en %U http://hdl.handle.net/1963/5496 %1 5340 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-02-16T07:58:53Z\\nNo. of bitstreams: 0 %] We consider a quantum mechanical system on a lattice \\\\mathbb {Z}^3 in which three particles, two of them being identical, interact through a zero-range potential. We admit a very general form for the \\\'kinetic\\\' part H0γ of the Hamiltonian, which contains a parameter γ to distinguish the two identical particles from the third one (in the continuum case this parameter would be the inverse of the mass). We prove that there is a value γ* of the parameter such that only for γ < γ* the Efimov effect (infinite number of bound states if the two-body interactions have a resonance) is absent for the sector of the Hilbert space which contains functions which are antisymmetric with respect to the two identical particles, while it is present for all values of γ on the symmetric sector. We comment briefly on the relation of this result with previous investigations on the Thomas effect. We also establish the following asymptotics for the number N(z) of eigenvalues z below Emin, the lower limit of the essential spectrum of H0. In the symmetric subspace \\\\lim _{z \\\\rightarrow E_{\\\\rm min}^- } { N^s(z) \\\\over | \\\\log | E_{\\\\rm min} -z| | } = \\\\mathcal {U}_0^s (\\\\gamma ), \\\\quad \\\\forall\\\\ \\\\gamma, whereas in the antisymmetric subspace \\\\lim _{z \\\\rightarrow E_{\\\\rm min}^- } { N^{as}(z) \\\\over | \\\\log | E_{\\\\rm min} -z| | } = \\\\mathcal {U}_0^{as} (\\\\gamma ), \\\\quad \\\\forall\\\\ \\\\gamma \\\\gt \\\\gamma ^*, where \\\\mathcal {U}_0^{ as } (\\\\gamma ), \\\\mathcal {U}_0^s (\\\\gamma ) are written explicitly as a function of the integral kernel of operators acting on L^2((0,r) \\\\times (L^2 (\\\\mathbb {S}^2) \\\\otimes L^2 (\\\\mathbb {S}^2)) (\\\\mathbb {S}^2 is the unit sphere in \\\\mathbb {R}^3). %R 10.1088/1751-8113/44/31/315302 %0 Journal Article %J Mathematical Models and Methods in Applied Sciences 21 (2011) 361-387 %D 2011 %T Numerical Strategies for Stroke Optimization of Axisymmetric Microswimmers %A Francois Alouges %A Antonio DeSimone %A Luca Heltai %K Optimal swimming %X We propose a computational method to solve optimal swimming problems, based on the boundary integral formulation of the hydrodynamic interaction between swimmer and surrounding fluid and direct constrained minimization of the energy consumed by the swimmer. We apply our method to axisymmetric model examples. We consider a classical model swimmer (the three-sphere swimmer of Golestanian et al.) as well as a novel axisymmetric swimmer inspired by the observation of biological micro-organisms. %B Mathematical Models and Methods in Applied Sciences 21 (2011) 361-387 %I World Scientific %G en_US %U http://hdl.handle.net/1963/3657 %1 648 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-06-23T17:30:51Z\\r\\nNo. of bitstreams: 1\\r\\nSissa33_2009M.pdf: 708341 bytes, checksum: 6134bd52f083488620fb5bb24bcf9b93 (MD5) %R 10.1142/S0218202511005088 %0 Journal Article %J SIAM J. Appl. Math. 71 (2011) 983-1008 %D 2011 %T Numerical Study of breakup in generalized Korteweg-de Vries and Kawahara equations %A Boris Dubrovin %A Tamara Grava %A Christian Klein %X This article is concerned with a conjecture in [B. Dubrovin, Comm. Math. Phys., 267 (2006), pp. 117–139] on the formation of dispersive shocks in a class of Hamiltonian dispersive regularizations of the quasi-linear transport equation. The regularizations are characterized by two arbitrary functions of one variable, where the condition of integrability implies that one of these functions must not vanish. It is shown numerically for a large class of equations that the local behavior of their solution near the point of gradient catastrophe for the transport equation is described by a special solution of a Painlevé-type equation. This local description holds also for solutions to equations where blowup can occur in finite time. Furthermore, it is shown that a solution of the dispersive equations away from the point of gradient catastrophe is approximated by a solution of the transport equation with the same initial data, modulo terms of order $\\\\epsilon^2$, where $\\\\epsilon^2$ is the small dispersion parameter. Corrections up to order $\\\\epsilon^4$ are obtained and tested numerically. %B SIAM J. Appl. Math. 71 (2011) 983-1008 %I SIAM %G en %U http://hdl.handle.net/1963/4951 %1 4732 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-27T12:18:45Z\\nNo. of bitstreams: 1\\n1101.0268v1.pdf: 522533 bytes, checksum: d9e2df220724f918ec3b888cef3593d4 (MD5) %R 10.1137/100819783 %0 Journal Article %J Rendiconti Lincei - Matematica e Applicazioni 22 (2011) 3-15 %D 2011 %T Osservazioni sui teoremi di inversione globale %A Antonio Ambrosetti %X Some global inversion theorems with applications to semilinear elliptic equation are discussed. %B Rendiconti Lincei - Matematica e Applicazioni 22 (2011) 3-15 %I European Mathematical Society %G en_US %U http://hdl.handle.net/1963/4068 %1 334 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-09-20T10:54:19Z\\r\\nNo. of bitstreams: 1\\r\\nAmbrosetti_64M_2010.pdf: 208213 bytes, checksum: 21e1562f4cbcd9ceb8c1b8c8afe9e442 (MD5) %R 10.4171/RLM/584 %0 Journal Article %J Proceedings of the American Mathematical Society 139 (2011) 4445-4459 %D 2011 %T Planar loops with prescribed curvature: existence, multiplicity and uniqueness results %A Roberta Musina %K Plane curves %B Proceedings of the American Mathematical Society 139 (2011) 4445-4459 %I American Mathematical Society %G en_US %U http://hdl.handle.net/1963/3842 %1 867 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-02-08T14:32:58Z\\r\\nNo. of bitstreams: 1\\r\\nMusina_loops.pdf: 273296 bytes, checksum: f8e3d605bca8421d5c606f9e490c911b (MD5) %R 10.1090/S0002-9939-2011-10915-8 %0 Journal Article %J Physics Letters A 375 (2011) 3496-3498 %D 2011 %T Poincaré covariance and κ-Minkowski spacetime %A Ludwik Dabrowski %A Gherardo Piacitelli %X A fully Poincaré covariant model is constructed out of the k-Minkowski spacetime. Covariance is implemented by a unitary representation of the Poincaré group, and thus complies with the original Wigner approach to quantum symmetries. This provides yet another example (besides the DFR model), where Poincaré covariance is realised á la Wigner in the presence of two characteristic dimensionful parameters: the light speed and the Planck length. In other words, a Doubly Special Relativity (DSR) framework may well be realised without deforming the meaning of \\\"Poincaré covariance\\\". %B Physics Letters A 375 (2011) 3496-3498 %I Elsevier %G en_US %U http://hdl.handle.net/1963/3893 %1 816 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-07-23T11:27:21Z\\r\\nNo. of bitstreams: 1\\r\\npiacitelli_43FM.pdf: 292672 bytes, checksum: 3aaa83de9dbf151351756897dbbcda09 (MD5) %R 10.1016/j.physleta.2011.08.011 %0 Journal Article %J Communications in Mathematical Physics 304 (2011) 395-409 %D 2011 %T Poincare\\\' polynomial of moduli spaces of framed sheaves on (stacky) Hirzebruch surfaces %A Ugo Bruzzo %A Rubik Poghossian %A Alessandro Tanzini %X We perform a study of the moduli space of framed torsion-free sheaves on Hirzebruch surfaces by using localization techniques. We discuss some general properties of this moduli space by studying it in the framework of Huybrechts-Lehn theory of framed modules. We classify the fixed points under a toric action on the moduli space, and use this to compute the Poincare polynomial of the latter. This will imply that the moduli spaces we are considering are irreducible. We also consider fractional first Chern classes, which means that we are extending our computation to a stacky deformation of a Hirzebruch surface. From the physical viewpoint, our results provide the partition function of N=4 Vafa-Witten theory on total spaces of line bundles on P1, which is relevant in black hole entropy counting problems according to a conjecture due to Ooguri, Strominger and Vafa. %B Communications in Mathematical Physics 304 (2011) 395-409 %I Springer %G en_US %U http://hdl.handle.net/1963/3738 %1 579 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-09-09T09:26:43Z\\r\\nNo. of bitstreams: 1\\r\\nBPT-8.pdf: 250954 bytes, checksum: 984c30f0144339468a97f54d6b22ce05 (MD5) %R 10.1007/s00220-011-1231-z %0 Journal Article %J Communications in Mathematical Physics, Volume 304, Issue 2, June 2011, Pages 395-409 %D 2011 %T Poincare polynomial of moduli spaces of framed sheaves on (stacky) Hirzebruch surfaces %A Ugo Bruzzo %A Rubik Poghossian %A Alessandro Tanzini %X We perform a study of the moduli space of framed torsion-free sheaves on\r\nHirzebruch surfaces by using localization techniques. We discuss some general\r\nproperties of this moduli space by studying it in the framework of\r\nHuybrechts-Lehn theory of framed modules. We classify the fixed points under a\r\ntoric action on the moduli space, and use this to compute the Poincare\r\npolynomial of the latter. This will imply that the moduli spaces we are\r\nconsidering are irreducible. We also consider fractional first Chern classes,\r\nwhich means that we are extending our computation to a stacky deformation of a\r\nHirzebruch surface. From the physical viewpoint, our results provide the\r\npartition function of N=4 Vafa-Witten theory on total spaces of line bundles on\r\nP1, which is relevant in black hole entropy counting problems according to a\r\nconjecture due to Ooguri, Strominger and Vafa. %B Communications in Mathematical Physics, Volume 304, Issue 2, June 2011, Pages 395-409 %I SISSA %G en %U http://hdl.handle.net/1963/6569 %1 6529 %2 Mathematics %4 1 %$ Submitted by Alessandro Tanzini (tanzini@sissa.it) on 2013-04-04T10:06:56Z\nNo. of bitstreams: 1\n0909.1458v2.pdf: 217483 bytes, checksum: 4ce0456502af2e734b679e4c7180081e (MD5) %R 10.1007/s00220-011-1231-z %0 Journal Article %J International Journal of Geometric Methods in Modern Physics 8 (2011) 1833-1848 %D 2011 %T Product of real spectral triples %A Ludwik Dabrowski %A Giacomo Dossena %X We construct the product of real spectral triples of arbitrary finite dimension (and arbitrary parity) taking into account the fact that in the even case there are two possible real structures, in the odd case there are two inequivalent representations of the gamma matrices (Clifford algebra), and in the even-even case there are two natural candidates for the Dirac operator of the product triple. %B International Journal of Geometric Methods in Modern Physics 8 (2011) 1833-1848 %I World Scientific %G en %U http://hdl.handle.net/1963/5510 %1 5345 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-02-16T16:08:08Z\\nNo. of bitstreams: 1\\n1011.4456v1.pdf: 279 bytes, checksum: 44d0388a861dfb41e598ee6d79dc9d01 (MD5) %R 10.1142/S021988781100597X %0 Journal Article %J Mathematische Zeitschrift 268 (2011) 371-407 %D 2011 %T A proof of Sudakov theorem with strictly convex norms %A Laura Caravenna %X We establish a solution to the Monge problem in Rn, with an asymmetric, strictly convex norm cost function, when the initial measure is absolutely continuous. We focus on the strategy, based on disintegration of measures, initially proposed by Sudakov. As known, there is a gap to fill. The missing step is completed when the unit ball is strictly convex, but not necessarily differentiable nor uniformly convex. The key disintegration is achieved following a similar proof for a variational problem. %B Mathematische Zeitschrift 268 (2011) 371-407 %I Springer %G en_US %U http://hdl.handle.net/1963/2967 %1 1733 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-24T10:14:57Z\\r\\nNo. of bitstreams: 1\\r\\nsudStrConv.pdf: 432852 bytes, checksum: 0c4df310f125711293cef790005abc33 (MD5) %R 10.1007/s00209-010-0677-6 %0 Report %D 2011 %T Q-factorial Laurent rings %A Ugo Bruzzo %A Antonella Grassi %X Dolgachev proved that, for any field k, the ring naturally associated to a\\r\\ngeneric Laurent polynomial in d variables, $d \\\\geq 4$, is factorial. We prove a\\r\\nsufficient condition for the ring associated to a very general complex Laurent\\r\\npolynomial in d=3 variables to be Q-factorial. %I SISSA %G en %U http://hdl.handle.net/1963/4183 %1 3907 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-22T10:50:24Z\\nNo. of bitstreams: 1\\n1108.4116v1.pdf: 105862 bytes, checksum: e65647872af8c9b70f2fe8466f37669a (MD5) %0 Journal Article %J Commun. Math. Phys. 308 (2011) 567-589 %D 2011 %T Quantum Geometry on Quantum Spacetime: Distance, Area and Volume Operators %A Dorothea Bahns %A Sergio Doplicher %A Klaus Fredenhagen %A Gherardo Piacitelli %X We develop the first steps towards an analysis of geometry on the quantum\\r\\nspacetime proposed in Doplicher et al. (Commun Math Phys 172:187–220, 1995). The homogeneous elements of the universal differential algebra are naturally identified with operators living in tensor powers of Quantum Spacetime; this allows us to compute their spectra. In particular, we consider operators that can be interpreted as distances, areas, 3- and 4-volumes. The Minkowski distance operator between two independent events is shown to have pure Lebesgue spectrum with infinite multiplicity. The Euclidean distance operator is shown to have spectrum bounded below by a constant of the order of the Planck length. The corresponding statement is proved also for both the space-space and space-time area operators, as well as for the Euclidean length of the vector representing the 3-volume operators. However, the space 3-volume operator (the time component of that vector) is shown to have spectrum equal to the whole complex plane. All these operators are normal, while the distance operators are also selfadjoint. The Lorentz invariant spacetime volume operator, representing the 4- volume spanned by five\\r\\nindependent events, is shown to be normal. Its spectrum is pure point with a\\r\\nfinite distance (of the order of the fourth power of the Planck length) away\\r\\nfrom the origin. The mathematical formalism apt to these problems is developed and its relation to a general formulation of Gauge Theories on Quantum Spaces is outlined. As a byproduct, a Hodge Duality between the absolute differential and the Hochschild boundary is pointed out. %B Commun. Math. Phys. 308 (2011) 567-589 %I Springer %G en %U http://hdl.handle.net/1963/5203 %1 5025 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-12-16T08:24:01Z\\nNo. of bitstreams: 1\\n1005.2130v1.pdf: 270027 bytes, checksum: d12021458a91ccdbfdaf8adfbb2ec89d (MD5) %R 10.1007/s00220-011-1358-y %0 Report %D 2011 %T Quantum Hitchin Systems via beta-deformed Matrix Models %A Giulio Bonelli %A Kazunobu Maruyoshi %A Alessandro Tanzini %X We study the quantization of Hitchin systems in terms of beta-deformations of generalized matrix models related to conformal blocks of Liouville theory on punctured Riemann surfaces. We show that in a suitable limit, corresponding to the Nekrasov-Shatashvili one, the loop equations of the matrix model reproduce the Hamiltonians of the quantum Hitchin system on the sphere and the torus with marked points. The eigenvalues of these Hamiltonians are shown to be the epsilon1-deformation of the chiral observables of the corresponding N=2 four\\r\\ndimensional gauge theory. Moreover, we find the exact wave-functions in terms of the matrix model representation of the conformal blocks with degenerate field insertions. %I SISSA %G en %U http://hdl.handle.net/1963/4181 %1 3904 %2 Physics %3 Elementary Particle Theory %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-22T10:22:35Z\\nNo. of bitstreams: 1\\n1104.4016v2.pdf: 317021 bytes, checksum: 92bcb534e0e6fdeb2e5c51517f28d510 (MD5) %0 Report %D 2011 %T Quantum Hitchin Systems via beta-deformed Matrix Models %A Giulio Bonelli %A Kazunobu Maruyoshi %A Alessandro Tanzini %X We study the quantization of Hitchin systems in terms of beta-deformations of\r\ngeneralized matrix models related to conformal blocks of Liouville theory on\r\npunctured Riemann surfaces. We show that in a suitable limit, corresponding to\r\nthe Nekrasov-Shatashvili one, the loop equations of the matrix model reproduce\r\nthe Hamiltonians of the quantum Hitchin system on the sphere and the torus with\r\nmarked points. The eigenvalues of these Hamiltonians are shown to be the\r\nepsilon1-deformation of the chiral observables of the corresponding N=2 four\r\ndimensional gauge theory. Moreover, we find the exact wave-functions in terms\r\nof the matrix model representation of the conformal blocks with degenerate\r\nfield insertions. %I SISSA %G en %U http://hdl.handle.net/1963/6572 %1 6527 %2 Mathematics %4 -1 %$ Submitted by Alessandro Tanzini (tanzini@sissa.it) on 2013-04-04T10:05:16Z\nNo. of bitstreams: 1\n1104.4016v2.pdf: 317021 bytes, checksum: 92bcb534e0e6fdeb2e5c51517f28d510 (MD5) %0 Journal Article %J Commun. Math. Phys. 307:101-131, 2011 %D 2011 %T Quantum Isometries of the finite noncommutative geometry of the Standard Model %A Jyotishman Bhowmick %A Francesco D\'Andrea %A Ludwik Dabrowski %X We compute the quantum isometry group of the finite noncommutative geometry F describing the internal degrees of freedom in the Standard Model of particle physics. We show that this provides genuine quantum symmetries of the spectral triple corresponding to M x F where M is a compact spin manifold. We also prove that the bosonic and fermionic part of the spectral action are preserved by these symmetries. %B Commun. Math. Phys. 307:101-131, 2011 %I Springer %G en %U http://hdl.handle.net/1963/4906 %1 4688 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-25T07:42:04Z\\nNo. of bitstreams: 1\\n1009.2850v3.pdf: 383426 bytes, checksum: 9d28d3070f7e7c39ec9486f40fd4f13b (MD5) %R 10.1007/s00220-011-1301-2 %0 Journal Article %J Journal of the Mechanics and Physics of Solids 59 (2011) 787-803 %D 2011 %T Quasiconvex envelopes of energies for nematic elastomers in the small strain regime and applications %A Pierluigi Cesana %A Antonio DeSimone %X We provide some explicit formulas for the quasiconvex envelope of energy densities for nematic elastomers in the small strain regime and plane strain conditions. We then demonstrate their use as a powerful tool for the interpretation of mechanical experiments. %B Journal of the Mechanics and Physics of Solids 59 (2011) 787-803 %G en_US %U http://hdl.handle.net/1963/4065 %1 337 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-09-15T10:43:52Z\\r\\nNo. of bitstreams: 1\\r\\nCesana_DeSimone_62M.pdf: 1146834 bytes, checksum: 514b1b282763c0351f234702f96e73f4 (MD5) %0 Journal Article %J ESAIM: COCV 17 (2011) 1-27 %D 2011 %T Quasistatic crack evolution for a cohesive zone model with different response to loading and unloading: a Young measures approach %A Filippo Cagnetti %A Rodica Toader %X A new approach to irreversible quasistatic fracture growth is given, by means of Young measures. The study concerns a cohesive zone model with prescribed crack path, when the material gives different responses to loading and unloading phases. In the particular situation of constant unloading response, the result contained in [6] is recovered. In this case, the convergence of the discrete time approximations is improved. %B ESAIM: COCV 17 (2011) 1-27 %I Cambridge University Press / EDP Sciences %G en_US %U http://hdl.handle.net/1963/2355 %1 1662 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-11-07T13:38:16Z\\r\\nNo. of bitstreams: 1\\r\\nQuasCrack.pdf: 298737 bytes, checksum: 127034af65efce0ab97317eccb47e76c (MD5) %R 10.1051/cocv/2009037 %0 Journal Article %J {ANNALI DI MATEMATICA PURA ED APPLICATA} %D 2011 %T Quasistatic crack growth in finite elasticity with Lipschitz data %A Giuliano Lazzaroni %K Brittle fracture %K Crack propagation %K Energy minimization %K Finite elasticity %K free-discontinuity problems %K Griffith's criterion %K Non-interpenetration} %K Polyconvexity %K Quasistatic evolution %K Rate-independent processes %K {Variational models %X{We extend the recent existence result of Dal Maso and Lazzaroni (Ann Inst H Poincare Anal Non Lineaire 27:257-290, 2010) for quasistatic evolutions of cracks in finite elasticity, allowing for boundary conditions and external forces with discontinuous first derivatives.}

%B {ANNALI DI MATEMATICA PURA ED APPLICATA} %I {SPRINGER HEIDELBERG} %C {TIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANY} %V {190} %P {165-194} %8 {JAN} %G eng %9 {Article} %R {10.1007/s10231-010-0145-2} %0 Journal Article %J Calculus of Variations and Partial Differential Equations 40 (2011) 125-181 %D 2011 %T Quasistatic evolution for Cam-Clay plasticity: a weak formulation via viscoplastic regularization and time rescaling %A Gianni Dal Maso %A Antonio DeSimone %A Francesco Solombrino %K Cam-Clay plasticity %X Cam-Clay nonassociative plasticity exhibits both hardening and softening behaviour, depending on the loading. For many initial data the classical formulation of the quasistatic evolution problem has no smooth solution. We propose here a notion of generalized solution, based on a viscoplastic approximation. To study the limit of the viscoplastic evolutions we rescale time, in such a way that the plastic strain is uniformly Lipschitz with respect to the rescaled time. The limit of these rescaled solutions, as the viscosity parameter tends to zero, is characterized through an energy-dissipation balance, that can be written in a natural way using the rescaled time. As shown in [4] and [6], the proposed solution may be discontinuous with respect to the original time. Our formulation allows to compute the amount of viscous dissipation occurring instantaneously at each discontinuity time. %B Calculus of Variations and Partial Differential Equations 40 (2011) 125-181 %I Springer %G en_US %U http://hdl.handle.net/1963/3670 %1 635 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-07-20T08:26:03Z\\r\\nNo. of bitstreams: 1\\r\\nDM-DeS-Sol-36_2009_preprint.pdf: 421582 bytes, checksum: 011806364200378d6deec80b88978550 (MD5) %R 10.1007/s00526-010-0336-0 %0 Journal Article %J Arch. Rational Mech. Anal. 202 (2011) 295-348 %D 2011 %T Quasistatic evolution of sessile drops and contact angle hysteresis %A Giovanni Alberti %A Antonio DeSimone %X We consider the classical model of capillarity coupled with a rate-independent dissipation mechanism due to frictional forces acting on the contact line, and prove the existence of quasistatic evolutions with prescribed initial configuration. We also discuss in detail some explicit solutions to show that the model does account for contact angle hysteresis, and to compare its predictions with experimental observations. %B Arch. Rational Mech. Anal. 202 (2011) 295-348 %I Springer %G en %U http://hdl.handle.net/1963/4912 %1 4693 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-25T09:46:50Z\\nNo. of bitstreams: 1\\ngads2.pdf: 620848 bytes, checksum: f5fef67c4e88cd294016f704c59394bd (MD5) %R 10.1007/s00205-011-0427-x %0 Journal Article %J Arch. Rational Mech. Anal. 200 (2011) 1003-1021 %D 2011 %T SBV regularity for Hamilton-Jacobi equations in $\\\\R^n$ %A Stefano Bianchini %A Camillo De Lellis %A Roger Robyr %X In this paper we study the regularity of viscosity solutions to the following\\r\\nHamilton-Jacobi equations $$ \\\\partial_t u + H(D_{x} u)=0 \\\\qquad \\\\textrm{in}\\r\\n\\\\Omega\\\\subset \\\\R\\\\times \\\\R^{n} . $$ In particular, under the assumption that the\\r\\nHamiltonian $H\\\\in C^2(\\\\R^n)$ is uniformly convex, we prove that $D_{x}u$ and\\r\\n$\\\\partial_t u$ belong to the class $SBV_{loc}(\\\\Omega)$. %B Arch. Rational Mech. Anal. 200 (2011) 1003-1021 %I Springer %G en %U http://hdl.handle.net/1963/4911 %1 4695 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-25T10:18:41Z\\nNo. of bitstreams: 1\\n1002.4087v1.pdf: 272486 bytes, checksum: 551dab603b0252ec9c22800b33360d02 (MD5) %R 10.1007/s00205-010-0381-z %0 Journal Article %J Advances in Mathematics 226 (2011) 3655-3676 %D 2011 %T Semistable and numerically effective principal (Higgs) bundles %A Ugo Bruzzo %A Beatriz Grana-Otero %X We study Miyaoka-type semistability criteria for principal Higgs G-bundles E on complex projective manifolds of any dimension. We prove that E has the property of being semistable after pullback to any projective curve if and only if certain line bundles, obtained from some characters of the parabolic subgroups of G, are numerically effective. One also proves that these conditions are met for semistable principal Higgs bundles whose adjoint bundle has vanishing second Chern class.\\r\\n\\r\\nIn a second part of the paper, we introduce notions of numerical effectiveness and numerical flatness for principal (Higgs) bundles, discussing their main properties. For (non-Higgs) principal bundles, we show that a numerically flat principal bundle admits a reduction to a Levi factor which has a flat Hermitian–Yang–Mills connection, and, as a consequence, that the cohomology ring of a numerically flat principal bundle with coefficients in R is trivial. To our knowledge this notion of numerical effectiveness is new even in the case of (non-Higgs) principal bundles. %B Advances in Mathematics 226 (2011) 3655-3676 %I Elsevier %G en_US %U http://hdl.handle.net/1963/3638 %1 666 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-05-18T12:30:35Z\\r\\nNo. of bitstreams: 1\\r\\nBruzzo_Otero.pdf: 270209 bytes, checksum: 843961bd72149ca85c9b100395b70ed1 (MD5) %R 10.1016/j.aim.2010.10.026 %0 Journal Article %J Indiana Univ. Math. J. 60 (2011) 367-409 %D 2011 %T Singular perturbation models in phase transitions for second order materials %A Milena Chermisi %A Gianni Dal Maso %A Irene Fonseca %A Giovanni Leoni %X A variational model proposed in the physics literature to describe the onset of pattern formation in two-component bilayer membranes and amphiphilic monolayers leads to the analysis of a Ginzburg-Landau type energy with a negative term depending on the first derivative of the phase function. Scaling arguments motivate the study of the family of second order singular perturbed energies Fe having a negative term depending on the first derivative of the phase function. Here, the asymptotic behavior of {Fe} is studied using G-convergence techniques. In particular, compactness results and an integral representation of the limit energy are obtained. %B Indiana Univ. Math. J. 60 (2011) 367-409 %I Indiana University %G en_US %U http://hdl.handle.net/1963/3858 %1 851 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-04-27T10:47:12Z\\r\\nNo. of bitstreams: 1\\r\\nCheDMaFonLeo_2010.pdf: 350746 bytes, checksum: b384a4d0b82dd9713e1849ad3ef6a2be (MD5) %R 10.1512/iumj.2011.60.4346 %0 Book Section %B Painlevé equations and related topics : proceedings of the international conference, Saint Petersburg, Russia, June 17-23, 2011 / Aleksandr Dmitrievich Briuno; Alexander B Batkhin. - Berlin : De Gruyter, [2012]. - p. 101-105 %D 2011 %T Solving PVI by Isomonodromy Deformations %A Davide Guzzetti %K Painlevé Equations %X The critical and asymptotic behaviors of solutions of the sixth Painlev\\\'e\r\nequation, an their parametrization in terms of monodromy data, are\r\nsynthetically reviewed. The explicit formulas are given. This paper has been\r\nwithdrawn by the author himself, because some improvements are necessary.\r\nThis is a proceedings of the international conference \"Painlevé Equations and Related Topics\" which was taking place at the Euler International Mathematical Institute, a branch of the Saint Petersburg Department of the SteklovInstitute of Mathematicsof theRussian Academy of Sciences, in Saint Petersburg on June 17 to 23, 2011. %B Painlevé equations and related topics : proceedings of the international conference, Saint Petersburg, Russia, June 17-23, 2011 / Aleksandr Dmitrievich Briuno; Alexander B Batkhin. - Berlin : De Gruyter, [2012]. - p. 101-105 %I SISSA %@ 9783110275582 %G en %U http://hdl.handle.net/1963/6522 %1 6472 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Davide Guzzetti (guzzetti@sissa.it) on 2013-03-12T10:34:39Z\nNo. of bitstreams: 1\n17-StPeterburg12.pdf: 53422 bytes, checksum: a79d3d4bf7aa7e55c929d66671e31dfe (MD5) %0 Journal Article %J Functional Analysis and its Applications, Volume 45, Issue 4, December 2011, Pages 241-251 %D 2011 %T On the Space of Symmetric Operators with Multiple Ground States %A Andrei Agrachev %K Multiple eigenvalue %X We study homological structure of the filtrations of the spaces of self-adjoint operators by the multiplicity of the ground state. We consider only operators acting in a finite dimensional complex or real Hilbert space but infinite dimensional generalizations are easily guessed. %B Functional Analysis and its Applications, Volume 45, Issue 4, December 2011, Pages 241-251 %I SISSA %G en %U http://hdl.handle.net/1963/7069 %1 6392 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-09-16T09:28:52Z No. of bitstreams: 1 1107.3010v2.pdf: 187825 bytes, checksum: 3e6e04aeadc87e130c87ada77fe862a1 (MD5) %R DOI: 10.1007/s10688-011-0026-5 %0 Journal Article %D 2011 %T On the space of symmetric operators with multiple ground states. %A Andrei Agrachev %I SISSA %1 6393 %2 Mathematics %0 Journal Article %J Journal of Dynamical and Control Systems 17 (2011) 141-161 %D 2011 %T The sphere and the cut locus at a tangency point in two-dimensional almost-Riemannian geometry %A Bernard Bonnard %A Grégoire Charlot %A Roberta Ghezzi %A Gabriel Janin %X We study the tangential case in 2-dimensional almost-Riemannian geometry. We\\r\\nanalyse the connection with the Martinet case in sub-Riemannian geometry. We\\r\\ncompute estimations of the exponential map which allow us to describe the\\r\\nconjugate locus and the cut locus at a tangency point. We prove that this last\\r\\none generically accumulates at the tangency point as an asymmetric cusp whose branches are separated by the singular set. %B Journal of Dynamical and Control Systems 17 (2011) 141-161 %I Springer %G en %U http://hdl.handle.net/1963/4914 %1 4692 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-25T09:38:15Z\\nNo. of bitstreams: 1\\n1009.2612v1.pdf: 263401 bytes, checksum: 0ddf4bcfd9663ee3c0da870233d119bb (MD5) %R 10.1007/s10883-011-9113-4 %0 Report %D 2011 %T Structure of level sets and Sard-type properties of Lipschitz maps %A Giovanni Alberti %A Stefano Bianchini %A Gianluca Crippa %I SISSA %G en %U http://hdl.handle.net/1963/4657 %1 4424 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-10-10T12:07:33Z\\nNo. of bitstreams: 1\\nAlberti_Bianchini_Crippa_51_M.pdf: 361735 bytes, checksum: b3f27bce1ab515dca94a6ad93d822160 (MD5) %0 Journal Article %J Int Math Res Notices (2011) 2011 (24): 5625-5643 %D 2011 %T Supercritical conformal metrics on surfaces with conical singularities %A Daniele Bartolucci %A Francesca De Marchis %A Andrea Malchiodi %X We study the problem of prescribing the Gaussian curvature on surfaces with conical singularities in supercritical regimes. Using a Morse-theoretical approach we prove a general existence theorem on surfaces with positive genus, with a generic multiplicity result. %B Int Math Res Notices (2011) 2011 (24): 5625-5643 %I Oxford University Press %G en_US %U http://hdl.handle.net/1963/4095 %1 309 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-10-26T07:12:29Z\\r\\nNo. of bitstreams: 1\\r\\nBarDemMal-56M.pdf: 317906 bytes, checksum: 6b2dc3222c15d6690b75440300fa4aed (MD5) %R 10.1093/imrn/rnq285 %0 Journal Article %J Int. Math. Res. Not. IMRN 2011, no. 24, 5625–5643. %D 2011 %T Supercritical conformal metrics on surfaces with conical singularities. %A Daniele Bartolucci %A Francesca De Marchis %A Andrea Malchiodi %B Int. Math. Res. Not. IMRN 2011, no. 24, 5625–5643. %I SISSA %G en %1 6491 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Andrea Malchiodi (malchiod@sissa.it) on 2013-03-14T10:31:48Z\nNo. of bitstreams: 0 %0 Journal Article %J Bioinformatics (Oxford, England). 2011 Dec; 27(24):3407-14 %D 2011 %T A system-level approach for deciphering the transcriptional response to prion infection %A Mattia Zampieri %A Giuseppe Legname %A Daniel Segrè %A Claudio Altafini %X MOTIVATION: Deciphering the response of a complex biological system to an insulting event, at the gene expression level, requires adopting theoretical models that are more sophisticated than a one-to-one comparison (i.e. t-test). Here, we investigate the ability of a novel reverse engineering approach (System Response Inference) to unveil non-obvious transcriptional signatures of the system response induced by prion infection.\\r\\nRESULTS: To this end, we analyze previously published gene expression data, from which we extrapolate a putative full-scale model of transcriptional gene-gene dependencies in the mouse central nervous system. Then, we use this nominal model to interpret the gene expression changes caused by prion replication, aiming at selecting the genes primarily influenced by this perturbation. Our method sheds light on the mode of action of prions by identifying key transcripts that are the most likely to be responsible for the overall transcriptional rearrangement from a nominal regulatory network. As a first result of our inference, we have been able to predict known targets of prions (i.e. PrP(C)) and to unveil the potential role of previously unsuspected genes.\\r\\nCONTACT: altafini@sissa.it\\r\\nSUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online. %B Bioinformatics (Oxford, England). 2011 Dec; 27(24):3407-14 %I Oxford University Press %G en %U http://hdl.handle.net/1963/5745 %1 5600 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-04-23T08:12:17Z\\nNo. of bitstreams: 1\\nZaLeSeAl11.pdf: 1229345 bytes, checksum: eb5500741d42ed30ef38112ebd4eae91 (MD5) %R 10.1093/bioinformatics/btr580 %0 Journal Article %J Calculus of Variations and Partial Differential Equations 41 (2011) 241-259 %D 2011 %T The time-dependent von Kármán plate equation as a limit of 3d nonlinear elasticity %A Helmut Abels %A Maria Giovanna Mora %A Stefan Müller %X The asymptotic behaviour of the solutions of three-dimensional nonlinear elastodynamics in a thin plate is studied, as the thickness $h$ of the plate tends to zero. Under appropriate scalings of the applied force and of the initial values in terms of $h$, it is shown that three-dimensional solutions of the nonlinear elastodynamic equation converge to solutions of the time-dependent von K\\\\\\\'arm\\\\\\\'an plate equation. %B Calculus of Variations and Partial Differential Equations 41 (2011) 241-259 %I Springer %G en_US %U http://hdl.handle.net/1963/3835 %1 492 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-01-26T16:49:12Z\\r\\nNo. of bitstreams: 1\\r\\n0912.4135v1.pdf: 217528 bytes, checksum: 4ee557860670b3d876174b2e053958e4 (MD5) %R 10.1007/s00526-010-0360-0 %0 Report %D 2011 %T A uniqueness result for the continuity equation in two dimensions %A Giovanni Alberti %A Stefano Bianchini %A Gianluca Crippa %I SISSA %G en %U http://hdl.handle.net/1963/4663 %1 4425 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-10-10T12:10:26Z\\nNo. of bitstreams: 1\\nAlberti_Bianchini_Crippa_52M.pdf: 318780 bytes, checksum: 556a1d21b44c58d90201b25b2c104744 (MD5) %0 Report %D 2011 %T Variational Implementation of Immersed Finite Element Methods %A Luca Heltai %A Francesco Costanzo %X Dirac-delta distributions are often crucial components of the solid-fluid\\r\\ncoupling operators in immersed solution methods for fluid-structure interaction (FSI) problems. This is certainly so for methods like the Immersed Boundary Method (IBM) or the Immersed Finite Element Method (IFEM), where Dirac-delta distributions are approximated via smooth functions. By contrast, a truly variational formulation of immersed methods does not require the use of Dirac-delta distributions, either formally or practically. This has been shown in the Finite Element Immersed Boundary Method (FEIBM), where the variational\\r\\nstructure of the problem is exploited to avoid Dirac-delta distributions at\\r\\nboth the continuous and the discrete level. In this paper, we generalize the\\r\\nFEIBM to the case where an incompressible Newtonian fluid interacts with a general hyperelastic solid. Specifically, we allow (i) the mass density to be different in the solid and the fluid, (ii) the solid to be either viscoelastic\\r\\nof differential type or purely elastic, and (iii) the solid to be and either\\r\\ncompressible or incompressible. At the continuous level, our variational\\r\\nformulation combines the natural stability estimates of the fluid and\\r\\nelasticity problems. In immersed methods, such stability estimates do not\\r\\ntransfer to the discrete level automatically due to the non- matching nature of the finite dimensional spaces involved in the discretization. After presenting our general mathematical framework for the solution of FSI problems, we focus in detail on the construction of natural interpolation operators between the fluid and the solid discrete spaces, which guarantee semi-discrete stability estimates and strong consistency of our spatial discretization. %I SISSA %G en %U http://hdl.handle.net/1963/4700 %1 4465 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-10-12T10:45:58Z\\nNo. of bitstreams: 1\\n1110.2063v1.pdf: 1433103 bytes, checksum: 73954809755f81dc1fe363ee99978e74 (MD5) %0 Report %D 2011 %T Wild Quiver Gauge Theories %A Giulio Bonelli %A Kazunobu Maruyoshi %A Alessandro Tanzini %X We study N=2 supersymmetric SU(2) gauge theories coupled to non-Lagrangian\r\nsuperconformal field theories induced by compactifying the six dimensional A_1\r\n(2,0) theory on Riemann surfaces with irregular punctures. These are naturally\r\nassociated to Hitchin systems with wild ramification whose spectral curves\r\nprovide the relevant Seiberg-Witten geometries. We propose that the\r\nprepotential of these gauge theories on the Omega-background can be obtained\r\nfrom the corresponding irregular conformal blocks on the Riemann surfaces via a\r\ngeneralization of the coherent state construction to the case of higher order\r\nsingularities. %I SISSA %G en %U http://hdl.handle.net/1963/6576 %1 6523 %2 Mathematics %4 -1 %$ Submitted by Alessandro Tanzini (tanzini@sissa.it) on 2013-04-04T10:01:39Z\nNo. of bitstreams: 1\n1112.1691v2.pdf: 374325 bytes, checksum: 2be807b77885e4467e7fdae0d4199168 (MD5) %0 Journal Article %J Annales de l'Institut Henri Poincare. Annales: Analyse Non Lineaire/Nonlinear Analysis %D 2010 %T An abstract Nash-Moser theorem with parameters and applications to PDEs %A Massimiliano Berti %A Philippe Bolle %A Procesi, M. %K Abstracting %K Aircraft engines %K Finite dimensional %K Hamiltonian PDEs %K Implicit function theorem %K Invariant tori %K Iterative schemes %K Linearized operators %K Mathematical operators %K Moser theorem %K Non-Linearity %K Nonlinear equations %K Nonlinear wave equation %K Periodic solution %K Point of interest %K Resonance phenomena %K Small divisors %K Sobolev %K Wave equations %X We prove an abstract Nash-Moser implicit function theorem with parameters which covers the applications to the existence of finite dimensional, differentiable, invariant tori of Hamiltonian PDEs with merely differentiable nonlinearities. The main new feature of the abstract iterative scheme is that the linearized operators, in a neighborhood of the expected solution, are invertible, and satisfy the "tame" estimates, only for proper subsets of the parameters. As an application we show the existence of periodic solutions of nonlinear wave equations on Riemannian Zoll manifolds. A point of interest is that, in presence of possibly very large "clusters of small divisors", due to resonance phenomena, it is more natural to expect solutions with only Sobolev regularity. © 2009 Elsevier Masson SAS. All rights reserved. %B Annales de l'Institut Henri Poincare. Annales: Analyse Non Lineaire/Nonlinear Analysis %V 27 %P 377-399 %G eng %R 10.1016/j.anihpc.2009.11.010 %0 Thesis %D 2010 %T Almost-Riemannian Geometry from a Control Theoretical Viewpoint %A Roberta Ghezzi %I SISSA %G en %U http://hdl.handle.net/1963/4705 %1 4482 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Davide Barilari (barilari@sissa.it) on 2011-10-13T08:13:37Z\\r\\nNo. of bitstreams: 1\\r\\nghezzi-PhD-thesis.pdf: 870834 bytes, checksum: 868d097fff7d3a6646b2bacc98dfeb4b (MD5) %0 Conference Proceedings %B PoS CNCFG2010:027,2010 %D 2010 %T Aspects of Quantum Field Theory on Quantum Spacetime %A Gherardo Piacitelli %X We provide a minimal, self-contained introduction to the covariant DFR flat\\r\\nquantum spacetime, and to some partial results for the corresponding quantum field theory. Explicit equations are given in the Dirac notation. %B PoS CNCFG2010:027,2010 %I SISSA %G en %U http://hdl.handle.net/1963/4171 %1 3893 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-09-20T14:32:21Z\\nNo. of bitstreams: 1\\n1103.3405v1.pdf: 305413 bytes, checksum: 094028cf6f36b4949d9db8c681bf4cec (MD5) %0 Report %D 2010 %T Canonical k-Minkowski Spacetime %A Gherardo Piacitelli %A Ludwik Dabrowski %X A complete classification of the regular representations of the relations [T,X_j] = (i/k)X_j, j=1,...,d, is given. The quantisation of RxR^d canonically (in the sense of Weyl) associated with the universal representation of the above relations is intrinsically \\\"radial\\\", this meaning that it only involves the time variable and the distance from the origin; angle variables remain classical. The time axis through the origin is a spectral singularity of the model: in the large scale limit it is topologically disjoint from the rest. The symbolic calculus is developed; in particular there is a trace functional on symbols. For suitable choices of states localised very close to the origin, the uncertainties of all spacetime coordinates can be made simultaneously small at wish. On the contrary, uncertainty relations become important at \\\"large\\\" distances: Planck scale effects should be visible at LHC energies, if processes are spread in a region of size 1mm (order of peak nominal beam size) around the origin of spacetime. %G en_US %U http://hdl.handle.net/1963/3863 %1 846 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-04-30T11:01:45Z\\r\\nNo. of bitstreams: 1\\r\\n1004.5091v1.pdf: 302332 bytes, checksum: 923a85fa3b4bef96bcf59c115bc3a61e (MD5) %0 Journal Article %J J. Geom. Phys. 60 (2010) 417-429 %D 2010 %T Chern-Simons theory on L(p,q) lens spaces and Gopakumar-Vafa duality %A Andrea Brini %A Luca Griguolo %A Domenico Seminara %A Alessandro Tanzini %X We consider aspects of Chern-Simons theory on L(p,q) lens spaces and its relation with matrix models and topological string theory on Calabi-Yau threefolds, searching for possible new large N dualities via geometric transition for non-SU(2) cyclic quotients of the conifold. To this aim we find, on one hand, some novel matrix integral representations of the SU(N) CS partition function in a generic flat background for the whole L(p,q) family and provide a solution for its large N dynamics; on the other, we perform in full detail the construction of a family of would-be dual closed string backgrounds via conifold geometric transition from T^*L(p,q). We can then explicitly prove that Gopakumar-Vafa duality in a fixed vacuum fails in the case q>1, and briefly discuss how it could be restored in a non-perturbative setting. %B J. Geom. Phys. 60 (2010) 417-429 %G en_US %U http://hdl.handle.net/1963/2938 %1 1762 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-12T16:01:18Z\\nNo. of bitstreams: 1\\n0809.1610v1.pdf: 287875 bytes, checksum: feadff501b37135585a6f62946b628de (MD5) %R 10.1016/j.geomphys.2009.11.006 %0 Report %D 2010 %T A Codazzi-like equation and the singular set for C1 smooth surfaces in the Heisenberg group %A Jih-Hsin Cheng %A Jenn-Fang Hwang %A Andrea Malchiodi %A Paul Yang %X In this paper, we study the structure of the singular set for a C1 smooth surface in the 3-dimensional Heisenberg group H1. We discover a Codazzi-like equation for the p-area element along the characteristic curves on\\nthe surface. Information obtained from this ordinary differential equation helps\\nus to analyze the local configuration of the singular set and the characteristic curves. In particular, we can estimate the size and obtain the regularity of the singular set. We understand the global structure of the singular set through a Hopf-type index theorem. We also justify that Codazzi-like equation by proving a fundamental theorem for local surfaces in H1. %G en_US %U http://hdl.handle.net/1963/4101 %1 303 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-11-10T13:08:17Z\\nNo. of bitstreams: 1\\nMalchiodi_76M.pdf: 550654 bytes, checksum: 2950a17ee24b4086b68ea041bdf9770f (MD5) %0 Report %D 2010 %T Cohomology of Skew-holomorphic lie algebroids %A Ugo Bruzzo %A Vladimir Rubtsov %X We introduce the notion of skew-holomorphic Lie algebroid on a complex manifold, and explore some cohomologies theories that one can associate to it. Examples are given in terms of holomorphic Poisson structures of various sorts. %G en_US %U http://hdl.handle.net/1963/3853 %1 856 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-03-08T11:09:57Z\\nNo. of bitstreams: 1\\nHolAlgCohom-2.pdf: 239431 bytes, checksum: 218e3d336432ad269f8f4c67e8d42fa5 (MD5) %0 Journal Article %J Ann. Inst. H. Poincare Anal. Non Lineaire 27 (2010) 37-56 %D 2010 %T Concentration of solutions for some singularly perturbed mixed problems: Asymptotics of minimal energy solutions %A Jesus Garcia Azorero %A Andrea Malchiodi %A Luigi Montoro %A Ireneo Peral %X In this paper we carry on the study of asymptotic behavior of some solutions to a singularly perturbed problem with mixed Dirichlet and Neumann boundary conditions, started in the first paper. Here we are mainly interested in the analysis of the location and shape of least energy solutions when the singular perturbation parameter tends to zero. We show that in many cases they coincide with the new solutions produced in. %B Ann. Inst. H. Poincare Anal. Non Lineaire 27 (2010) 37-56 %G en_US %U http://hdl.handle.net/1963/3409 %1 926 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-01-08T11:10:32Z\\nNo. of bitstreams: 1\\nGMMPII.pdf: 324708 bytes, checksum: 4829f5449fac58672d6e7a8e42efb3c4 (MD5) %R 10.1016/j.anihpc.2009.06.005 %0 Journal Article %J Arch. Ration. Mech. Anal. 196 (2010) 907-950 %D 2010 %T Concentration of solutions for some singularly perturbed mixed problems. Part I: existence results %A Jesus Garcia Azorero %A Andrea Malchiodi %A Luigi Montoro %A Ireneo Peral %X In this paper we study the asymptotic behavior of some solutions to a singularly perturbed problem with mixed Dirichlet and Neumann boundary conditions. We prove that, under suitable geometric conditions on the boundary of the domain, there exist solutions which approach the intersection of the Neumann and the Dirichlet parts as the singular perturbation parameter tends to zero. %B Arch. Ration. Mech. Anal. 196 (2010) 907-950 %G en_US %U http://hdl.handle.net/1963/3406 %1 927 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-01-08T11:03:36Z\\nNo. of bitstreams: 1\\nGMMPI.pdf: 466523 bytes, checksum: 004f66da4f9e531a535780337f19e185 (MD5) %R 10.1007/s00205-009-0259-0 %0 Journal Article %J Calculus of Variations and Partial Differential Equations. Volume 39, Issue 1, 2010, Pages 213-232 %D 2010 %T Continuity of optimal control costs and its application to weak KAM theory %A Andrei Agrachev %A P.W.Y. Lee %X We prove continuity of certain cost functions arising from optimal control of\\r\\naffine control systems. We give sharp sufficient conditions for this\\r\\ncontinuity. As an application, we prove a version of weak KAM theorem and\\r\\nconsider the Aubry-Mather problems corresponding to these systems. %B Calculus of Variations and Partial Differential Equations. Volume 39, Issue 1, 2010, Pages 213-232 %I SISSA %G en %U http://hdl.handle.net/1963/6459 %1 6405 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-02-05T14:56:31Z\\nNo. of bitstreams: 1\\n0909.3826v2.pdf: 264638 bytes, checksum: 5f13730dcb51f57d19a692ea1d6c48c6 (MD5) %R 10.1007/s00526-010-0308-4 %0 Report %D 2010 %T Convergence of equilibria of thin elastic rods under physical growth conditions for the energy density %A Elisa Davoli %A Maria Giovanna Mora %X The subject of this paper is the study of the asymptotic behaviour of the equilibrium configurations of a nonlinearly elastic thin rod, as the diameter of the cross-section tends to zero. Convergence results are established assuming physical growth conditions for the elastic energy density and suitable scalings of the applied loads, that correspond at the limit to different rod models: the constrained linear theory, the analogous of von Kármán plate theory for rods, and the linear theory. %G en_US %U http://hdl.handle.net/1963/4086 %1 317 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-10-05T08:49:01Z\\nNo. of bitstreams: 1\\nDavoli-Mora_67M_2010.pdf: 243056 bytes, checksum: 8542ff47b9dc1ae7275fe95bc296a870 (MD5) %0 Journal Article %J Comm. Math. Phys. 295 (2010) 731-790 %D 2010 %T Dirac Operators on Quantum Projective Spaces %A Francesco D\'Andrea %A Ludwik Dabrowski %X We construct a family of self-adjoint operators D_N which have compact resolvent and bounded commutators with the coordinate algebra of the quantum projective space CP_q(l), for any l>1 and 0\\\\R w.r.t. the partition into its faces, which are convex sets and therefore have a well defined linear dimension, and we prove that each conditional measure is equivalent to the k-dimensional Hausdorff measure of the k-dimensional face on which it is concentrated. The remarkable fact is that a priori the directions of the faces are just Borel and no Lipschitz regularity is known. Notwithstanding that, we also prove that a Green-Gauss formula for these directions holds on special sets. %B J. Funct. Anal. 258 (2010) 3604-3661 %G en_US %U http://hdl.handle.net/1963/3622 %1 682 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-04-24T15:53:31Z\\nNo. of bitstreams: 1\\ndisconvCaravDaneri.pdf: 759110 bytes, checksum: e22e069339fc07c3bde1855b76e61d1e (MD5) %R 10.1016/j.jfa.2010.01.024 %0 Journal Article %J Journal of Dynamical and Control Systems. Volume 16, Issue 2, April 2010, Pages :149-162 %D 2010 %T Dynamics control by a time-varying feedback %A Andrei Agrachev %A Marco Caponigro %K Discrete-time dynamics %X We consider a smooth bracket generating control-affine system in R^d and show that any orientation preserving diffeomorphism of R^d can be approximated, in the very strong sense, by a diffeomorphism included in the flow generated by a time-varying feedback control which is polynomial with respect to the state variables and trigonometric-polynomial with respect to the time variable. %B Journal of Dynamical and Control Systems. Volume 16, Issue 2, April 2010, Pages :149-162 %I SISSA %G en %U http://hdl.handle.net/1963/6461 %1 6407 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Approved for entry into archive by Lucio Lubiana (lubiana@sissa.it) on 2013-02-06T09:37:23Z (GMT) No. of bitstreams: 0 %R 10.1007/s10883-010-9087-7 %0 Journal Article %J J. Phys. A 43 (2010) 474014 %D 2010 %T Effective Schroedinger dynamics on $ ε$-thin Dirichlet waveguides via Quantum Graphs I: star-shaped graphs %A Gianfausto Dell'Antonio %A Emanuele Costa %X We describe the boundary conditions at the vertex that one must choose to obtain a dynamical system that best describes the low-energy part of the evolution of a quantum system confined to a very small neighbourhood of a star-shaped metric graph. %B J. Phys. A 43 (2010) 474014 %I IOP Publishing %G en_US %U http://hdl.handle.net/1963/4106 %1 298 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-12-06T13:09:12Z\\nNo. of bitstreams: 1\\n1004.4750v2.pdf: 273649 bytes, checksum: ff34b6647ba206615715d6c764115064 (MD5) %R 10.1088/1751-8113/43/47/474014 %0 Journal Article %J SIAM J. Math. Anal. 42 (2010) 1179-1217 %D 2010 %T Estimates on path functionals over Wasserstein Spaces %A Stefano Bianchini %A Alessio Brancolini %X In this paper we consider the class a functionals (introduced in [Brancolini, Buttazzo, and Santambrogio, J. Eur. Math. Soc. (JEMS), 8 (2006), pp. 415-434] $\\\\mathcal{G}_{r,p}$ defined on Lipschitz curves $\\\\gamma$ valued in the $p$-Wasserstein space. The problem considered is the following: given a measure $\\\\mu$, give conditions in order to assure the existence of a curve $\\\\gamma$ such that $\\\\gamma(0)=\\\\mu$, $\\\\gamma(1)=\\\\delta_{x_0}$, and $\\\\mathcal{G}_{r,p}(\\\\gamma)<+\\\\infty$. To this end, new estimates on $\\\\mathcal{G}_{r,p}(\\\\mu)$ are given, and a notion of dimension of a measure (called path dimension) is introduced: the path dimension specifies the values of the parameters $(r,p)$ for which the answer to the previous reachability problem is positive. Finally, we compare the path dimension with other known dimensions. %B SIAM J. Math. Anal. 42 (2010) 1179-1217 %G en_US %U http://hdl.handle.net/1963/3583 %1 717 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-03-09T09:05:25Z\\nNo. of bitstreams: 1\\nestimates_path_functionals.prerint.pdf: 356623 bytes, checksum: 6bc99a8752ef3aae9d1b91d05e8a2f8e (MD5) %R 10.1137/100782693 %0 Journal Article %J Math. Z. 265 (2010) 889-923 %D 2010 %T On the Euler-Lagrange equation for a variational problem : the general case II %A Stefano Bianchini %A Matteo Gloyer %B Math. Z. 265 (2010) 889-923 %G en_US %U http://hdl.handle.net/1963/2551 %1 1568 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-01-14T09:52:10Z\\nNo. of bitstreams: 1\\ngeneralcase.final.pdf: 315418 bytes, checksum: dee89d593fb956f4a377db9221520eb6 (MD5) %R 10.1007/s00209-009-0547-2 %0 Journal Article %J Ann. Inst. H. Poincare Anal. Non Lineaire 27 (2010) 1291-1331 %D 2010 %T Exact reconstruction of damaged color images using a total variation model %A Irene Fonseca %A Giovanni Leoni %A Francesco Maggi %A Massimiliano Morini %X In this paper the reconstruction of damaged piecewice constant color images is studied using a RGB total variation based model for colorization/inpainting. In particular, it is shown that when color is known in a uniformly distributed region, then reconstruction is possible with maximal fidelity. %B Ann. Inst. H. Poincare Anal. Non Lineaire 27 (2010) 1291-1331 %I Elsevier %G en_US %U http://hdl.handle.net/1963/4039 %1 363 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-09-06T09:54:56Z\\nNo. of bitstreams: 1\\nflmm.pdf: 434739 bytes, checksum: f315d8807349e077c524fe14a1619a56 (MD5) %R 10.1016/j.anihpc.2010.06.004 %0 Journal Article %J Proc. Steklov Inst. Math. 270 (2010) 43-56 %D 2010 %T Existence of planar curves minimizing length and curvature %A Ugo Boscain %A Grégoire Charlot %A Francesco Rossi %X In this paper we consider the problem of reconstructing a curve that is partially hidden or corrupted by minimizing the functional $\\\\int \\\\sqrt{1+K_\\\\gamma^2} ds$, depending both on length and curvature $K$. We fix starting and ending points as well as initial and final directions.\\nFor this functional we discuss the problem of existence of minimizers on various functional spaces. We find non-existence of minimizers in cases in which initial and final directions are considered with orientation. In this case, minimizing sequences of trajectories can converge to curves with angles.\\nWe instead prove existence of minimizers for the \\\"time-reparameterized\\\" functional $$\\\\int \\\\| \\\\dot\\\\gamma(t) \\\\|\\\\sqrt{1+K_\\\\ga^2} dt$$ for all boundary conditions if initial and final directions are considered regardless to orientation. In this case, minimizers can present cusps (at most two) but not angles. %B Proc. Steklov Inst. Math. 270 (2010) 43-56 %I Springer %G en_US %U http://hdl.handle.net/1963/4107 %1 297 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-12-06T13:30:01Z\\nNo. of bitstreams: 1\\n0906.5290v2.pdf: 305594 bytes, checksum: 3966f5a798b69743ce88a29bf73edc47 (MD5) %R 10.1134/S0081543810030041 %0 Journal Article %J Systems and Control Letters, 59 (12):782-786, 2010 %D 2010 %T Feedback schemes for radiation damping suppression in NMR: a control-theoretical perspective %A Claudio Altafini %A Paola Cappellaro %A David Cory %X In NMR spectroscopy, the collective measurement is weakly invasive and its back-action is called radiation damping. The aim of this paper is to provide a control-theoretical analysis of the problem of suppressing this radiation damping. It is shown that the two feedback schemes commonly used in the NMR practice correspond one to a high gain oputput feedback for the simple case of maintaining the spin 1/2 in its inverted state, and the second to a 2-degree of freedom control design with a prefeedback that exactly cancels the radiation damping field. A general high gain feedback stabilization design not requiring the knowledge of the radiation damping time constant is also investigated. %B Systems and Control Letters, 59 (12):782-786, 2010 %I Elsevier %G en %U http://hdl.handle.net/1963/4384 %1 4132 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-09-30T10:33:33Z\\nNo. of bitstreams: 1\\nAlCaCo09.pdf: 172729 bytes, checksum: b8f2ae1517b057b5f24fd2d8b3666002 (MD5) %R 10.1016/j.sysconle.2010.09.004 %0 Journal Article %J Rend. Istit. Mat. Univ. Trieste 42 (2010) 103-128 %D 2010 %T Gauge theory: from physics to geometry %A Ugo Bruzzo %X Maxwell theory may be regarded as a prototype of gauge theory and generalized to nonabelian gauge theory. We briey sketch the history of the gauge theories, from Maxwell to Yang-Mills theory, and the identification of gauge fields with connections on fibre bundles. We introduce the notion of instanton and consider the moduli spaces of such objects. Finally, we discuss some modern techniques for studying the topology of these moduli spaces. %B Rend. Istit. Mat. Univ. Trieste 42 (2010) 103-128 %I Istituto di matematica. Universita\\\' di Trieste %G en_US %U http://hdl.handle.net/1963/4105 %1 299 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-11-17T09:12:32Z\\r\\nNo. of bitstreams: 1\\r\\nBruzzo_80FM.pdf: 651780 bytes, checksum: 65c68609e094a11090d91cf1207e2c2b (MD5) %0 Journal Article %J The European journal of neuroscience. 2010 Oct; 32(8):1364-79 %D 2010 %T Gene expression analysis of the emergence of epileptiform activity after focal injection of kainic acid into mouse hippocampus. %A Dario Motti %A Caroline Le Duigou %A Nicole Chemaly %A Lucia Wittner %A Dejan Lazarevic %A Helena Krmac %A Troels Torben Marstrand %A Eivind Valen %A Remo Sanges %A Elia Stupka %A Albin Sandelin %A Enrico Cherubini %A Stefano Gustincich %A Richard Miles %XWe report gene profiling data on genomic processes underlying the progression towards recurrent seizures after injection of kainic acid (KA) into the mouse hippocampus. Focal injection enabled us to separate the effects of proepileptic stimuli initiated by KA injection. Both the injected and contralateral hippocampus participated in the status epilepticus. However, neuronal death induced by KA treatment was restricted to the injected hippocampus, although there was some contralateral axonal degeneration. We profiled gene expression changes in dorsal and ventral regions of both the injected and contralateral hippocampus. Changes were detected in the expression of 1526 transcripts in samples from three time-points: (i) during the KA-induced status epilepticus, (ii) at 2 weeks, before recurrent seizures emerged, and (iii) at 6 months after seizures emerged. Grouping genes with similar spatio-temporal changes revealed an early transcriptional response, strong immune, cell death and growth responses at 2 weeks and an activation of immune and extracellular matrix genes persisting at 6 months. Immunostaining for proteins coded by genes identified from array studies provided evidence for gliogenesis and suggested that the proteoglycan biglycan is synthesized by astrocytes and contributes to a glial scar. Gene changes at 6 months after KA injection were largely restricted to tissue from the injection site. This suggests that either recurrent seizures might depend on maintained processes including immune responses and changes in extracellular matrix proteins near the injection site or alternatively might result from processes, such as growth, distant from the injection site and terminated while seizures are maintained.

%B The European journal of neuroscience. 2010 Oct; 32(8):1364-79 %I Wiley %G en %U http://hdl.handle.net/1963/4480 %1 4244 %2 Neuroscience %3 Neurobiology %4 -1 %$ Approved for entry into archive by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-05T07:58:51Z (GMT) No. of bitstreams: 0 %R 10.1111/j.1460-9568.2010.07403.x %0 Journal Article %J Int. Math. Res. Not. (2010) 2010:279-296 %D 2010 %T On the geometric origin of the bi-Hamiltonian structure of the Calogero-Moser system %A Claudio Bartocci %A Gregorio Falqui %A Igor Mencattini %A Giovanni Ortenzi %A Marco Pedroni %X We show that the bi-Hamiltonian structure of the rational n-particle (attractive) Calogero-Moser system can be obtained by means of a double projection from a very simple Poisson pair on the cotangent bundle of gl(n,R). The relation with the Lax formalism is also discussed. %B Int. Math. Res. Not. (2010) 2010:279-296 %I Oxford University Press %G en_US %U http://hdl.handle.net/1963/3800 %1 8 %2 LISNU %3 Interdisciplinary Laboratory for Advanced Studies %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-11-26T17:50:52Z\\nNo. of bitstreams: 1\\n0902.0953v2.pdf: 202665 bytes, checksum: 95f41e27482c7e7a0d598e06ea7e7763 (MD5) %R 10.1093/imrn/rnp130 %0 Report %D 2010 %T The geometry emerging from the symmetries of a quantum system %A Giuseppe De Nittis %A Gianluca Panati %X We investigate the relation between the symmetries of a quantum system and its topological quantum numbers, in a general C*-algebraic framework. We prove that, under suitable assumptions on the symmetry algebra, there exists a generalization of the Bloch-Floquet transform which induces a direct-integral decomposition of the algebra of observables. Such generalized transform selects uniquely the set of \\\"continuous sections\\\" in the direct integral, thus yielding a Hilbert bundle. The emerging geometric structure provides some topological invariants of the quantum system. Two running examples provide an Ariadne\\\'s thread through the paper. For the sake of completeness, we review two related theorems by von Neumann and Maurin and compare them with our result. %G en_US %U http://hdl.handle.net/1963/3834 %1 493 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-01-26T16:38:34Z\\nNo. of bitstreams: 1\\n0911.5270v2.pdf: 578198 bytes, checksum: a06ef54ebf418d5d7b6d0a7c3410c054 (MD5) %0 Journal Article %J Journal of Physics A: Mathematical and Theoretical. Volume 43, Issue 43, 29 October 2010, Article number 434002 %D 2010 %T Hamiltonian PDEs: deformations, integrability, solutions %A Boris Dubrovin %X We review recent classification results on the theory of systems of nonlinear\\r\\nHamiltonian partial differential equations with one spatial dimension, including\\r\\na perturbative approach to the integrability theory of such systems, and discuss\\r\\nuniversality conjectures describing critical behaviour of solutions to such\\r\\nsystems. %B Journal of Physics A: Mathematical and Theoretical. Volume 43, Issue 43, 29 October 2010, Article number 434002 %I SISSA %G en %U http://hdl.handle.net/1963/6469 %1 6414 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Boris Dubrovin (dubrovin@sissa.it) on 2013-02-11T14:36:26Z\\nNo. of bitstreams: 0 %R 10.1088/1751-8113/43/43/434002 %0 Journal Article %J Phys. Lett. B 691 (2010) 111-115 %D 2010 %T Hitchin systems, N=2 gauge theories and W-gravity %A Giulio Bonelli %A Alessandro Tanzini %X We propose some arguments supporting an M-theory derivation of the duality recently discovered by Alday, Gaiotto and Tachikawa between two-dimensional conformal field theories and N=2 superconformal gauge theories in four dimensions. We find that A_{N-1} Toda field theory is the simplest two-dimensional conformal field theory quantizing the moduli of N M5-branes wrapped on a Riemann surface. This leads us to identify chiral operators of the N=2 gauge theories with W-algebra currents. As a check of this correspondence we study some relevant OPE\\\'s obtaining that Nekrasov\\\'s partition function satisfies W-geometry constraints. %B Phys. Lett. B 691 (2010) 111-115 %G en_US %U http://hdl.handle.net/1963/3831 %1 496 %2 Physics %3 Elementary Particle Theory %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-01-26T15:40:23Z\\nNo. of bitstreams: 1\\n0909.4031.pdf: 120604 bytes, checksum: 7f2242b71035ba7cad650ea81a13d801 (MD5) %R 10.1016/j.physletb.2010.06.027 %0 Journal Article %J Phys. Rev. A 81 (2010) 062335 %D 2010 %T Homogeneous binary trees as ground states of quantum critical Hamiltonians %A Pietro Silvi %A Vittorio Giovannetti %A Simone Montangero %A Matteo Rizzi %A J. Ignacio Cirac %A Rosario Fazio %X Many-body states whose wave-function admits a representation in terms of a uniform binary-tree tensor decomposition are shown to obey to power-law two-body correlations functions. Any such state can be associated with the ground state of a translational invariant Hamiltonian which, depending on the dimension of the systems sites, involve at most couplings between third-neighboring sites. A detailed analysis of their spectra shows that they admit an exponentially large ground space. %B Phys. Rev. A 81 (2010) 062335 %I American Physical Society %G en_US %U http://hdl.handle.net/1963/3909 %1 800 %2 Physics %3 Condensed Matter Theory %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-07-27T07:32:21Z\\nNo. of bitstreams: 1\\n0912.0466v1.pdf: 336415 bytes, checksum: 7220d67cfb58f794aa50037140db23e6 (MD5) %R 10.1103/PhysRevA.81.062335 %0 Journal Article %J New J. Phys. 12 (2010) 075018 %D 2010 %T Homogeneous multiscale entanglement renormalization ansatz tensor networks for quantum critical systems %A Matteo Rizzi %A Simone Montangero %A Pietro Silvi %A Vittorio Giovannetti %A Rosario Fazio %X In this paper, we review the properties of homogeneous multiscale entanglement renormalization ansatz (MERA) to describe quantum critical systems.We discuss in more detail our results for one-dimensional (1D) systems (the Ising and Heisenberg models) and present new data for the 2D Ising model. Together with the results for the critical exponents, we provide a detailed description of the numerical algorithm and a discussion of new optimization\\nstrategies. The relation between the critical properties of the system and the tensor structure of the MERA is expressed using the formalism of quantum channels, which we review and extend. %B New J. Phys. 12 (2010) 075018 %I IOP Publishing %G en_US %U http://hdl.handle.net/1963/4067 %1 335 %2 Physics %3 Condensed Matter Theory %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-09-16T09:50:44Z\\nNo. of bitstreams: 1\\n10081611392421027.pdf: 1233170 bytes, checksum: 39da921aa8c098e7c8d6451b0ce08c15 (MD5) %R 10.1088/1367-2630/12/7/075018 %0 Journal Article %J Adv. Calc. Var. 3 (2010) 345-370 %D 2010 %T Homogenization of fiber reinforced brittle material: the intermediate case %A Gianni Dal Maso %A Caterina Ida Zeppieri %X We derive a cohesive fracture model by homogenizing a periodic composite material whose microstructure is characterized by the presence of brittle inclusions in a reticulated unbreakable elastic structure. %B Adv. Calc. Var. 3 (2010) 345-370 %I Walter de Gruyter %G en_US %U http://hdl.handle.net/1963/3607 %1 694 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-04-02T10:43:00Z\\r\\nNo. of bitstreams: 1\\r\\nDM-Zep.pdf: 294507 bytes, checksum: 5ba95ca12abb15953a564aeedf353087 (MD5) %R 10.1515/ACV.2010.011 %0 Journal Article %J Russian Mathematical Surveys. Volume 65, Issue 5, 2010, Pages: 977-978 %D 2010 %T Invariant Lagrange submanifolds of dissipative systems %A Andrei Agrachev %X We study solutions of modified Hamilton-Jacobi equations H(du/dq,q) + cu(q) =\\r\\n0, q \\\\in M, on a compact manifold M . %B Russian Mathematical Surveys. Volume 65, Issue 5, 2010, Pages: 977-978 %I SISSA %G en %U http://hdl.handle.net/1963/6457 %1 6403 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-02-05T14:35:25Z\\nNo. of bitstreams: 1\\n0912.2248v2.pdf: 74166 bytes, checksum: 6c6c803e56c96e455631b40eb7ef91b5 (MD5) %R 10.1070/RM2010v065n05ABEH004707 %0 Journal Article %J Mathematical Biosciences and Engineering 7(2):301-312, 2010 %D 2010 %T A kinetic mechanism inducing oscillations in simple chemical reactions networks %A Julien Coatleven %A Claudio Altafini %X It is known that a kinetic reaction network in which one or more secondary substrates are acting as cofactors may exhibit an oscillatory behavior. The aim of this work is to provide a description of the functional form of such a cofactor action guaranteeing the\\r\\nonset of oscillations in sufficiently simple reaction networks. %B Mathematical Biosciences and Engineering 7(2):301-312, 2010 %I American Institute of Mathematical Sciences %G en_US %U http://hdl.handle.net/1963/2393 %1 2304 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-11-12T13:08:42Z\\r\\nNo. of bitstreams: 1\\r\\nCoAl07.pdf: 254781 bytes, checksum: 0906fef8209903070cd78781f52b13b1 (MD5) %R 10.3934/mbe.2010.7.301 %0 Journal Article %J Phys. Rev. D 81 (2010) 125024 %D 2010 %T Lorentz Covariant k-Minkowski Spacetime %A Ludwik Dabrowski %A Michal Godlinski %A Gherardo Piacitelli %X In recent years, different views on the interpretation of Lorentz covariance of non commuting coordinates were discussed. Here, by a general procedure, we construct the minimal canonical central covariantisation of the k-Minkowski spacetime. We then show that, though the usual k-Minkowski spacetime is covariant under deformed (or twisted) Lorentz action, the resulting framework is equivalent to taking a non covariant restriction of the covariantised model. We conclude with some general comments on the approach of deformed covariance. %B Phys. Rev. D 81 (2010) 125024 %G en_US %U http://hdl.handle.net/1963/3829 %1 498 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-01-26T15:05:30Z\\nNo. of bitstreams: 1\\n0912.5451v2.pdf: 189407 bytes, checksum: e0a9a6af9e79410c0a199250cb168d04 (MD5) %R 10.1103/PhysRevD.81.125024 %0 Report %D 2010 %T The Monge problem in geodesic spaces %A Stefano Bianchini %A Fabio Cavalletti %G en_US %U http://hdl.handle.net/1963/3873 %1 836 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-06-07T11:02:40Z\\nNo. of bitstreams: 1\\nBianchini_Cavalletti.pdf: 197076 bytes, checksum: 751023683db266f751c4adf3a75379bf (MD5) %0 Journal Article %J BMC Systems Biology 2010, 4:83 %D 2010 %T Monotonicity, frustration, and ordered response: an analysis of the energy landscape of perturbed large-scale biological networks %A Giovanni Iacono %A Claudio Altafini %X Background. \\nFor large-scale biological networks represented as signed graphs, the index of frustration measures how far a network is from a monotone system, i.e., how incoherently the system responds to perturbations.\\nResults. \\nIn this paper we find that the frustration is systematically lower in transcriptional networks (modeled at functional level) than in signaling and metabolic networks (modeled at stoichiometric level). A possible interpretation of this result is in terms of energetic cost of an interaction: an erroneous or contradictory transcriptional action costs much more than a signaling/metabolic error, and therefore must be avoided as much as possible. Averaging over all possible perturbations, however, we also find that unlike for transcriptional networks, in the signaling/metabolic networks the probability of finding the system in its least frustrated configuration tends to be high also in correspondence of a moderate energetic regime, meaning that, in spite of the higher frustration, these networks can achieve a globally ordered response to perturbations even for moderate values of the strength of the interactions. Furthermore, an analysis of the energy landscape shows that signaling and metabolic networks lack energetic barriers around their global optima, a property also favouring global order.\\nConclusion. \\nIn conclusion, transcriptional and signaling/metabolic networks appear to have systematic differences in both the index of frustration and the transition to global order. These differences are interpretable in terms of the different functions of the various classes of networks. %B BMC Systems Biology 2010, 4:83 %I BioMed Central %G en_US %U http://hdl.handle.net/1963/4055 %1 347 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-09-13T10:31:59Z\\nNo. of bitstreams: 1\\n1752-0509-4-83.pdf: 1153140 bytes, checksum: 11a6235e8d975094d5fefbdb911af66b (MD5) %R 10.1186/1752-0509-4-83 %0 Report %D 2010 %T Moore-Read Fractional Quantum Hall wavefunctions and SU(2) quiver gauge theories %A Raoul Santachiara %A Alessandro Tanzini %X We identify Moore-Read wavefunctions, describing non-abelian statistics in fractional quantum Hall systems, with the instanton partition of N=2 superconformal quiver gauge theories at suitable values of masses and \\\\Omega-background parameters. This is obtained by extending to rational conformal field theories the SU(2) gauge quiver/Liouville field theory duality recently found by Alday-Gaiotto-Tachikawa. A direct link between the Moore-Read Hall $n$-body wavefunctions and Z_n-equivariant Donaldson polynomials is pointed out. %G en_US %U http://hdl.handle.net/1963/3852 %1 857 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-03-02T08:00:48Z\\nNo. of bitstreams: 1\\n14_2010_FM.pdf: 390526 bytes, checksum: 871ac8b351d4f1610b0120a9e7a5201a (MD5) %0 Journal Article %J Adv. Calc. Var. 3 (2010) 287-319 %D 2010 %T Nonlocal character of the reduced theory of thin films with higher order perturbations %A Gianni Dal Maso %A Irene Fonseca %A Giovanni Leoni %B Adv. Calc. Var. 3 (2010) 287-319 %G en_US %U http://hdl.handle.net/1963/3754 %1 563 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-09-15T09:06:42Z\\nNo. of bitstreams: 1\\nDM-Fon-Leo.pdf: 288658 bytes, checksum: 7815e9376b53eb044b2fb2b57cd49b53 (MD5) %R 10.1515/ACV.2010.012, /July/2010 %0 Report %D 2010 %T On the number of positive solutions of some semilinear elliptic problems %A Antonio Ambrosetti %G en_US %U http://hdl.handle.net/1963/4083 %1 320 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-10-04T09:32:44Z\\nNo. of bitstreams: 1\\nAmbrosetti_66M_2010.pdf: 141739 bytes, checksum: c56d5c17199fdefcd3d62c0b2da958a1 (MD5) %0 Report %D 2010 %T Numerical Solution of the Small Dispersion Limit of the Camassa-Holm and Whitham Equations and Multiscale Expansions %A Simonetta Abenda %A Tamara Grava %A Christian Klein %X The small dispersion limit of solutions to the Camassa-Holm (CH) equation is characterized by the appearance of a zone of rapid modulated oscillations. An asymptotic description of these oscillations is given, for short times, by the one-phase solution to the CH equation, where the branch points of the corresponding elliptic curve depend on the physical coordinates via the Whitham equations. We present a conjecture for the phase of the asymptotic solution. A numerical study of this limit for smooth hump-like initial data provides strong evidence for the validity of this conjecture.... %G en_US %U http://hdl.handle.net/1963/3840 %1 487 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-02-05T10:20:56Z\\nNo. of bitstreams: 1\\n0909.1020v1.pdf: 613403 bytes, checksum: be892250a6d664faff51d74b323fea67 (MD5) %0 Journal Article %J Comptes Rendus Mathematique 348 (2010) 613-618 %D 2010 %T On optimality of c-cyclically monotone transference plans %A Stefano Bianchini %A Laura Caravenna %X Abstract. This note deals with the equivalence between the optimality of a transport plan for the Monge-Kantorovich problem and the condition of c-cyclical monotonicity, as an outcome of the construction in [7]. We emphasize the measurability assumption on the hidden structure of linear preorder, applied also to extremality and uniqueness problems. Resume. Dans la presente note nous decrivons brievement la construction introduite dans [7] a propos de l\\\'equivalence entre l\\\'optimalite d\\\'un plan de transport pour le probleme de Monge-Kantorovich et la condition de monotonie c-cyclique ainsi que d\\\'autres sujets que cela nous amene a aborder. Nous souhaitons mettre en evidence l\\\'hypothese de mesurabilite sur la structure sous-jacente de pre-ordre lineaire. %B Comptes Rendus Mathematique 348 (2010) 613-618 %I Elsevier %G en_US %U http://hdl.handle.net/1963/4023 %1 379 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-09-02T09:13:11Z\\nNo. of bitstreams: 1\\ncmonoNoteCRM.pdf: 154086 bytes, checksum: f2efc74ccfedd2e335ff99ff279b5cfd (MD5) %R 10.1016/j.crma.2010.03.022 %0 Report %D 2010 %T Optimally swimming Stokesian Robots %A Francois Alouges %A Antonio DeSimone %A Luca Heltai %A Aline Lefebvre %A Benoit Merlet %X We study self propelled stokesian robots composed of assemblies of balls, in dimen-\\nsions 2 and 3, and prove that they are able to control their position and orientation. This is a result of controllability, and its proof relies on applying Chow\\\'s theorem in an analytic framework, similarly to what has been done in [3] for an axisymmetric system swimming along the axis of symmetry. However, we simplify drastically\\nthe analyticity result given in [3] and apply it to a situation where more complex swimmers move either in a plane or in three-dimensional space, hence experiencing also rotations. We then focus our attention on energetically optimal strokes, which we are able to compute numerically. Some examples of computed optimal strokes are discussed in detail. %G en_US %U http://hdl.handle.net/1963/3929 %1 472 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-07-29T11:02:56Z\\nNo. of bitstreams: 1\\nHeltai_54M_2010.pdf: 993075 bytes, checksum: 77225380bab031438ac940e694ea0e6c (MD5) %0 Journal Article %J Comm. Pure Appl. Math. 63 (2010) 203-232 %D 2010 %T Painlevé II asymptotics near the leading edge of the oscillatory zone for the Korteweg-de Vries equation in the small-dispersion limit %A Tom Claeys %A Tamara Grava %X In the small dispersion limit, solutions to the Korteweg-de Vries equation develop an interval of fast oscillations after a certain time. We obtain a universal asymptotic expansion for the Korteweg-de Vries solution near the leading edge of the oscillatory zone up to second order corrections. This expansion involves the Hastings-McLeod solution of the Painlev\\\\\\\'e II equation. We prove our results using the Riemann-Hilbert approach. %B Comm. Pure Appl. Math. 63 (2010) 203-232 %I Wiley %G en_US %U http://hdl.handle.net/1963/3799 %1 527 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-11-26T16:48:15Z\\nNo. of bitstreams: 1\\n0812.4142v1.pdf: 343118 bytes, checksum: 4bf2fa3751076c18466f29e1163acc09 (MD5) %R 10.1002/cpa.20277 %0 Report %D 2010 %T Picard group of hypersurfaces in toric varieties %A Ugo Bruzzo %A Antonella Grassi %X We show that the usual sufficient criterion for a generic hypersurface in a smooth projective manifold to have the same Picard number as the ambient variety can be generalized to hypersurfaces in complete simplicial toric varieties. This sufficient condition is always satisfied by generic K3 surfaces embedded in Fano toric 3-folds. %G en_US %U http://hdl.handle.net/1963/4103 %1 301 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-11-17T08:32:53Z\\nNo. of bitstreams: 1\\nBruzzo_78FM.pdf: 196280 bytes, checksum: 4025c3d0687d1cf714b24bdff1e33568 (MD5) %0 Journal Article %J Nonlinearity. vol. 23, (2010), page 2501-2507 %D 2010 %T Poles of Integrale Tritronquee and Anharmonic Oscillators. Asymptotic localization from WKB analysis %A Davide Masoero %XPoles of integrale tritronquee are in bijection with cubic oscillators that admit the simultaneous solutions of two quantization conditions. We show that the poles lie near the solutions of a pair of Bohr-Sommerfeld quantization conditions (the Bohr-Sommerfeld-Boutroux system): the distance between a pole and the corresponding solution of the Bohr-Sommerfeld-Boutroux system vanishes asymptotically.

%B Nonlinearity. vol. 23, (2010), page 2501-2507 %G en_US %U http://hdl.handle.net/1963/3841 %1 486 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-02-05T13:17:03Z No. of bitstreams: 1 1002.1042v1.pdf: 166705 bytes, checksum: eebb138b8560474f3bc975c18b76da51 (MD5) %R 10.1088/0951-7715/23/10/008 %0 Journal Article %J ESAIM COCV 16 (2010) 275-297 %D 2010 %T Projective Reeds-Shepp car on $S^2$ with quadratic cost %A Ugo Boscain %A Francesco Rossi %X Fix two points $x,\\\\bar{x}\\\\in S^2$ and two directions (without orientation) $\\\\eta,\\\\bar\\\\eta$ of the velocities in these points. In this paper we are interested to the problem of minimizing the cost $$ J[\\\\gamma]=\\\\int_0^T g_{\\\\gamma(t)}(\\\\dot\\\\gamma(t),\\\\dot\\\\gamma(t))+\\nK^2_{\\\\gamma(t)}g_{\\\\gamma(t)}(\\\\dot\\\\gamma(t),\\\\dot\\\\gamma(t)) ~dt$$ along all smooth curves starting from $x$ with direction $\\\\eta$ and ending in $\\\\bar{x}$ with direction $\\\\bar\\\\eta$. Here $g$ is the standard Riemannian metric on $S^2$ and $K_\\\\gamma$ is the corresponding geodesic curvature.\\nThe interest of this problem comes from mechanics and geometry of vision. It can be formulated as a sub-Riemannian problem on the lens space L(4,1).\\nWe compute the global solution for this problem: an interesting feature is that some optimal geodesics present cusps. The cut locus is a stratification with non trivial topology. %B ESAIM COCV 16 (2010) 275-297 %G en_US %U http://hdl.handle.net/1963/2668 %1 1429 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-06-11T11:22:54Z\\nNo. of bitstreams: 1\\n0805.4800v1.pdf: 610220 bytes, checksum: b0fa81a60fc43e6da6a4682e91b4d21e (MD5) %R 10.1051/cocv:2008075 %0 Report %D 2010 %T Quantum Spacetime: a Disambiguation %A Gherardo Piacitelli %X We review an approach to non-commutative geometry, where models are constructed by quantisation of the coordinates. In particular we focus on the full DFR model and its irreducible components; the (arbitrary) restriction to a particular irreducible component is often referred to as the \\\"canonical quantum spacetime\\\". The aim is to distinguish and compare the approaches under various points of view, including motivations, prescriptions for quantisation, the choice of mathematical objects and concepts, approaches to dynamics and to covariance. Some incorrect statements as \\\"universality of Planck scale conflicts with Lorentz-Fitzgerald contraction and requires a modification of covariance\\\", or \\\"stability of the geometric background requires an absolute lower bound of (\\\\Delta x^\\\\mu)\\\", or \\\"violations of unitarity are due to time/space non-commutativity\\\" are put in context, and discussed. %G en_US %U http://hdl.handle.net/1963/3864 %1 845 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-04-30T11:06:32Z\\r\\nNo. of bitstreams: 1\\r\\n1004.5261v1.pdf: 529975 bytes, checksum: d7fe48852cac62ba9266e61f93413bd0 (MD5) %0 Journal Article %J Arch. Ration. Mech. Anal. 196 (2010) 867-906 %D 2010 %T Quasistatic crack growth in elasto-plastic materials: the two-dimensional case %A Gianni Dal Maso %A Rodica Toader %X We study a variational model for the quasistatic evolution of elasto-plastic materials with cracks in the case of planar small strain associative elasto-plasticity. %B Arch. Ration. Mech. Anal. 196 (2010) 867-906 %G en_US %U http://hdl.handle.net/1963/2964 %1 1736 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-23T17:17:34Z\\nNo. of bitstreams: 1\\nDM-Toa-07-preprint.pdf: 320979 bytes, checksum: e4f2a1856f9bd91d63fc45557cbd6a16 (MD5) %R 10.1007/s00205-009-0258-1 %0 Journal Article %J Ann. Inst. H. Poincare Anal. Non Lineaire 27 (2010) 257-290 %D 2010 %T Quasistatic crack growth in finite elasticity with non-interpenetration %A Gianni Dal Maso %A Giuliano Lazzaroni %X We present a variational model to study the quasistatic growth of brittle cracks in hyperelastic materials, in the framework of finite elasticity, taking\\ninto account the non-interpenetration condition. %B Ann. Inst. H. Poincare Anal. Non Lineaire 27 (2010) 257-290 %G en_US %U http://hdl.handle.net/1963/3397 %1 935 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-12-15T09:16:46Z\\nNo. of bitstreams: 1\\nDM-Laz-08pre.pdf: 360778 bytes, checksum: 14a35b4647fde0ea0931df8ae6cbfb73 (MD5) %R 10.1016/j.anihpc.2009.09.006 %0 Journal Article %J Netw. Heterog. Media 5 (2010) 97-132 %D 2010 %T Quasistatic evolution for Cam-Clay plasticity: the spatially homogeneous case %A Gianni Dal Maso %A Francesco Solombrino %K Cam-Clay plasticity %X We study the spatially uniform case of the problem of quasistatic evolution in small strain nonassociative elastoplasticity (Cam-Clay model). Through the introdution of a viscous approximation, the problem reduces to determine the limit behavior of the solutions of a singularly perturbed system of ODE\\\'s in a finite dimensional Banach space. Depending on the sign of two explicit scalar indicators, we see that the limit dynamics presents, under quite generic assumptions, the alternation of three possible regimes: the elastic regime, when the limit equation is just the equation of linearized elasticity, the slow dynamics, when the strain evolves smoothly on the yield surface and plastic flow is produced, and the fast dynamics, which may happen only in the softening regime, where\\nviscous solutions exhibit a jump across a heteroclinic orbit of an auxiliary system. %B Netw. Heterog. Media 5 (2010) 97-132 %G en_US %U http://hdl.handle.net/1963/3671 %1 634 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-07-20T08:35:17Z\\nNo. of bitstreams: 1\\nDM-Sol2-39_2009_preprint.pdf: 345995 bytes, checksum: 073ce622e3320be1f56a1cc9f8904fae (MD5) %R 10.3934/nhm.2010.5.97 %0 Journal Article %J J. Phys. A 43 (2010) 045201 %D 2010 %T The reductions of the dispersionless 2D Toda hierarchy and their Hamiltonian structures %A Guido Carlet %A Paolo Lorenzoni %A Andrea Raimondo %X We study finite-dimensional reductions of the dispersionless 2D Toda hierarchy showing that the consistency conditions for such reductions are given by a system of radial Loewner equations. We then construct their Hamiltonian structures, following an approach proposed by Ferapontov. %B J. Phys. A 43 (2010) 045201 %I IOP Publishing %G en_US %U http://hdl.handle.net/1963/3846 %1 863 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-02-17T09:13:18Z\\nNo. of bitstreams: 1\\n0910.1210v1.pdf: 183431 bytes, checksum: 90f5253ca8e81822f6ffb26ece621075 (MD5) %R 10.1088/1751-8113/43/4/045201 %0 Journal Article %J Geom. Topol. 14 (2010) 83-115 %D 2010 %T Riemann-Roch theorems and elliptic genus for virtually smooth schemes %A Barbara Fantechi %A Lothar Göttsche %X For a proper scheme X with a fixed 1-perfect obstruction theory, we define virtual versions of holomorphic Euler characteristic, chi y-genus, and elliptic genus; they are deformation invariant, and extend the usual definition in the smooth case. We prove virtual versions of the Grothendieck-Riemann-Roch and Hirzebruch-Riemann-Roch theorems. We show that the virtual chi y-genus is a polynomial, and use this to define a virtual topological Euler characteristic. We prove that the virtual elliptic genus satisfies a Jacobi modularity property; we state and prove a localization theorem in the toric equivariant case. We show how some of our results apply to moduli spaces of stable sheaves. %B Geom. Topol. 14 (2010) 83-115 %I Mathematical Sciences Publishers %G en_US %U http://hdl.handle.net/1963/3888 %1 821 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-07-23T07:35:11Z\\nNo. of bitstreams: 1\\n0706.0988v1.pdf: 396801 bytes, checksum: 640403457a0a02c4166b8c684d8af419 (MD5) %R 10.2140/gt.2010.14.83 %0 Report %D 2010 %T The role of membrane viscosity in the dynamics of fluid membranes %A Marino Arroyo %A Antonio DeSimone %A Luca Heltai %X Fluid membranes made out of lipid bilayers are the fundamental separation structure in eukaryotic cells. Many physiological processes rely on dramatic shape and topological changes (e.g. fusion, fission) of fluid membrane systems. Fluidity is key to the versatility and constant reorganization of lipid bilayers. Here, we study the role of the membrane intrinsic viscosity, arising from the friction of the lipid molecules as they rearrange to accommodate shape changes, in the dynamics of morphological changes of fluid vesicles. In particular, we analyze the competition between the membrane viscosity and the viscosity of the bulk fluid surrounding the vesicle as the dominant dissipative mechanism. We consider the relaxation dynamics of fluid vesicles put in an out-of-equilibrium state, but conclusions can be drawn regarding the kinetics or power consumption in regulated shape changes in the cell. On the basis of numerical calculations, we find that the dynamics arising from the membrane viscosity are qualitatively different from the dynamics arising from the bulk viscosity. When these two dissipation mechanisms are put in competition, we find that for small vesicles the membrane dissipation dominates, with a relaxation time that scales as the size of the vesicle to the power 2. For large vesicles, the bulk dissipation dominates, and the exponent in the relaxation time vs. size relation is 3. %G en_US %U http://hdl.handle.net/1963/3930 %1 471 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-07-29T11:13:35Z\\nNo. of bitstreams: 1\\nArroyo_55M.pdf: 4419667 bytes, checksum: ca8a9c175a457ad33996d46a08e85e44 (MD5) %0 Journal Article %J Geom. Dedicata 146 (2010) 27-41 %D 2010 %T On semistable principal bundles over complex projective manifolds, II %A Indranil Biswas %A Ugo Bruzzo %X Let (X, \\\\omega) be a compact connected Kaehler manifold of complex dimension d and E_G a holomorphic principal G-bundle on X, where G is a connected reductive linear algebraic group defined over C. Let Z (G) denote the center of G. We prove that the following three statements are equivalent: (1) There is a parabolic subgroup P of G and a holomorphic reduction of the structure group of E_G to P (say, E_P) such that the bundle obtained by extending the structure group of E_P to L(P)/Z(G) (where L(P) is the Levi quotient of P) admits a flat connection; (2) The adjoint vector bundle ad(E_G) is numerically flat; (3) The principal G-bundle E_G is pseudostable, and the degree of the charateristic class c_2(ad(E_G) is zero. %B Geom. Dedicata 146 (2010) 27-41 %G en_US %U http://hdl.handle.net/1963/3404 %1 928 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-12-31T11:15:29Z\\nNo. of bitstreams: 1\\nbiswas-bruzzo-2.pdf: 216946 bytes, checksum: 21a4d096140b009d34e486648fe1a555 (MD5) %R 10.1007/s10711-009-9424-8 %0 Report %D 2010 %T Sharp nonexistence results for a linear elliptic inequality involving Hardy and Leray potentials %A Mouhamed Moustapha Fall %A Roberta Musina %X In this paper we deal with nonnegative distributional supersolutions for a class of linear\\nelliptic equations involving inverse-square potentials and logarithmic weights. We prove sharp nonexistence results. %G en_US %U http://hdl.handle.net/1963/3869 %1 840 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-05-28T10:38:12Z\\nNo. of bitstreams: 1\\nFall_Musina_2010.pdf: 232933 bytes, checksum: cfcad2e3f6d3120912888f823d290d5c (MD5) %0 Journal Article %J Ann. Scuola Norm. Sup. Pisa Cl. Sci. (5) Vol. IX (2010) 253-295 %D 2010 %T Shell theories arising as low energy Gamma-limit of 3d nonlinear elasticity %A Marta Lewicka %A Maria Giovanna Mora %A Mohammad Reza Pakzad %X We discuss the limiting behavior (using the notion of gamma-limit) of the 3d nonlinear elasticity for thin shells around an arbitrary smooth 2d surface. In particular, under the assumption that the elastic energy of deformations scales like h4, h being the thickness of a shell, we derive a limiting theory which is a generalization of the von Karman theory for plates. %B Ann. Scuola Norm. Sup. Pisa Cl. Sci. (5) Vol. IX (2010) 253-295 %G en_US %U http://hdl.handle.net/1963/2601 %1 1521 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-03-11T11:36:01Z\\nNo. of bitstreams: 1\\nLewMorPak08.pdf: 342797 bytes, checksum: 4293029876d53186e1ecce89c98e5c0c (MD5) %R 10.2422/2036-2145.2010.2.02 %0 Journal Article %J Archive for Rational Mechanics and Analysis %D 2010 %T Sobolev periodic solutions of nonlinear wave equations in higher spatial dimensions %A Massimiliano Berti %A Philippe Bolle %X We prove the existence of Cantor families of periodic solutions for nonlinear wave equations in higher spatial dimensions with periodic boundary conditions. We study both forced and autonomous PDEs. In the latter case our theorems generalize previous results of Bourgain to more general nonlinearities of class C k and assuming weaker non-resonance conditions. Our solutions have Sobolev regularity both in time and space. The proofs are based on a differentiable Nash-Moser iteration scheme, where it is sufficient to get estimates of interpolation-type for the inverse linearized operators. Our approach works also in presence of very large "clusters of small divisors". © Springer-Verlag (2009). %B Archive for Rational Mechanics and Analysis %V 195 %P 609-642 %G eng %R 10.1007/s00205-008-0211-8 %0 Journal Article %J SIAM J. Math. Anal. 42 (2010) 2132-2154 %D 2010 %T Solitonic asymptotics for the Korteweg-de Vries equation in the small dispersion limit %A Tamara Grava %A Tom Claeys %X We study the small dispersion limit for the Korteweg-de Vries (KdV) equation $u_t+6uu_x+\\\\epsilon^{2}u_{xxx}=0$ in a critical scaling regime where $x$ approaches the trailing edge of the region where the KdV solution shows oscillatory behavior. Using the Riemann-Hilbert approach, we obtain an asymptotic expansion for the KdV solution in a double scaling limit, which shows that the oscillations degenerate to sharp pulses near the trailing edge. Locally those pulses resemble soliton solutions of the KdV equation. %B SIAM J. Math. Anal. 42 (2010) 2132-2154 %G en_US %U http://hdl.handle.net/1963/3839 %1 488 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-02-05T10:12:44Z\\nNo. of bitstreams: 1\\n0911.5686v1.pdf: 311708 bytes, checksum: bfe41688febbfb066ebaae202e1e93b6 (MD5) %R 10.1137/090779103 %0 Journal Article %D 2010 %T Sub-Riemannian structures on 3D Lie groups %A Andrei Agrachev %A Davide Barilari %X We give a complete classification of left-invariant sub-Riemannian structures\\r\\non three dimensional Lie groups in terms of the basic differential invariants.\\r\\nAs a corollary we explicitly find a sub-Riemannian isometry between the\\r\\nnonisomorphic Lie groups SL(2) and $A^+(\\\\R)\\\\times S^1$, where $A^+(\\\\R)$ denotes the group of orientation preserving affine maps on the real line. %I SISSA %G en %U http://hdl.handle.net/1963/4699 %1 4464 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Davide Barilari (barilari@sissa.it) on 2011-10-12T08:01:12Z\\nNo. of bitstreams: 1\\n3dSLast.pdf: 321809 bytes, checksum: a5808da24547be1f960049d4769574e1 (MD5) %0 Journal Article %J JHEP 06(2010)063 %D 2010 %T Taming open/closed string duality with a Losev trick %A Giulio Bonelli %A Andrea Prudenziati %A Alessandro Tanzini %X A target space string field theory formulation for open and closed B-model is provided by giving a Batalin-Vilkovisky quantization of the holomorphic Chern-Simons theory with off-shell gravity background. The target space expression for the coefficients of the holomorphic anomaly equation for open strings are obtained. Furthermore, open/closed string duality is proved from a judicious integration over the open string fields. In particular, by restriction to the case of independence on continuous open moduli, the shift formulas of [7] are reproduced and shown therefore to encode the data of a closed string dual. %B JHEP 06(2010)063 %G en_US %U http://hdl.handle.net/1963/3855 %1 854 %2 Physics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-04-27T10:19:29Z\\nNo. of bitstreams: 1\\nBonelli_1003.2519v2.pdf: 244116 bytes, checksum: e9e48e420eda839f478ab8a4da3e7136 (MD5) %R 10.1007/JHEP06(2010)063 %0 Journal Article %J Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology %D 2010 %T A three-dimensional model for the dynamics and hydrodynamics of rowing boats %A L Formaggia %A A Mola %A N Parolini %A M Pischiutta %X This paper proposes a new model describing the dynamics of a rowing boat for general three-dimensional motions. The complex interaction between the different components of the rowers–-oars–-boat system is analysed and reduced to a set of ordinary differential equations governing the rigid motion along the six degrees of freedom. To treat the unstable nature of the physical problem, a rather simple (but effective) control model is included, which mimics the main active control techniques adopted by the rowers during their action. %B Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology %V 224 %P 51-61 %G eng %R 10.1243/17543371JSET46 %0 Journal Article %J Annales Henri Poincare 11 (2010) 539-564 %D 2010 %T A time-dependent perturbative analysis for a quantum particle in a cloud chamber %A Gianfausto Dell'Antonio %A Rodolfo Figari %A Alessandro Teta %X We consider a simple model of a cloud chamber consisting of a test particle (the alpha-particle) interacting with two other particles (the atoms of the vapour) subject to attractive potentials centered in $a_1, a_2 \\\\in \\\\mathbb{R}^3$. At time zero the alpha-particle is described by an outgoing spherical wave centered in the origin and the atoms are in their ground state. We show that, under suitable assumptions on the physical parameters of the system and up to second order in perturbation theory, the probability that both atoms are ionized is negligible unless $a_2$ lies on the line joining the origin with $a_1$. The work is a fully time-dependent version of the original analysis proposed by Mott in 1929. %B Annales Henri Poincare 11 (2010) 539-564 %I Springer %G en_US %U http://hdl.handle.net/1963/3969 %1 432 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-08-05T08:05:00Z\\nNo. of bitstreams: 1\\n0907.5503v1.pdf: 273181 bytes, checksum: 781ee2f8d4ce957ebbfbf866bcc40d2b (MD5) %R 10.1007/s00023-010-0037-4 %0 Journal Article %J Comm. Math. Phys. 295 (2010) 701-729 %D 2010 %T Twisted Covariance as a Non Invariant Restriction of the Fully Covariant DFR Model %A Gherardo Piacitelli %X We discuss twisted covariance over the noncommutative spacetime algebra generated by the relations [q_theta^mu,q_theta^nu]=i theta^{mu nu}, where the matrix theta is treated as fixed (not a tensor), and we refrain from using the asymptotic Moyal expansion of the twists. We show that the tensor nature of theta is only hidden in the formalism: in particular if theta fulfils the DFR conditions, the twisted Lorentz covariant model of the flat quantum spacetime may be equivalently described in terms of the DFR model, if we agree to discard a huge non invariant set of localisation states; it is only this last step which, if taken as a basic assumption, severely breaks the relativity principle. We also will show that the above mentioned, relativity breaking, ad hoc rejection of localisation states is an independent, unnecessary assumption, as far as some popular approaches to quantum field theory on the quantum Minkowski spacetime are concerned. The above should raise some concerns about speculations on possible observable consequences of arbitrary choices of theta in arbitrarily selected privileged frames. %B Comm. Math. Phys. 295 (2010) 701-729 %G en_US %U http://hdl.handle.net/1963/3605 %1 696 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-03-25T14:20:42Z\\nNo. of bitstreams: 1\\npiacitel.pdf: 380229 bytes, checksum: 7d138b9f702c50d5404fb8b9bfbac84c (MD5) %R 10.1007/s00220-010-0988-9 %0 Journal Article %J Ann. Inst. H. Poincare Anal. Non Lineaire 27 (2010) 793-807 %D 2010 %T Two-dimensional almost-Riemannian structures with tangency points %A Andrei Agrachev %A Ugo Boscain %A Grégoire Charlot %A Roberta Ghezzi %A Mario Sigalotti %X Two-dimensional almost-Riemannian structures are generalized Riemannian structures on surfaces for which a local orthonormal frame is given by a Lie bracket generating pair of vector fields that can become collinear. We study the relation between the topological invariants of an almost-Riemannian structure on a compact oriented surface and the rank-two vector bundle over the surface which defines the structure. We analyse the generic case including the presence of tangency points, i.e. points where two generators of the distribution and their Lie bracket are linearly dependent. The main result of the paper provides a classification of oriented almost-Riemannian structures on compact oriented surfaces in terms of the Euler number of the vector bundle corresponding to the structure. Moreover, we present a Gauss-Bonnet formula for almost-Riemannian structures with tangency points. %B Ann. Inst. H. Poincare Anal. Non Lineaire 27 (2010) 793-807 %I Elsevier %G en_US %U http://hdl.handle.net/1963/3870 %1 839 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-05-31T14:15:39Z\\nNo. of bitstreams: 1\\n0908.2564v1.pdf: 302590 bytes, checksum: 15369151ee10bb886dc6678350dee7f5 (MD5) %R 10.1016/j.anihpc.2009.11.011 %0 Report %D 2010 %T Uhlenbeck-Donaldson compactification for framed sheaves on projective surfaces %A Ugo Bruzzo %A Dimitri Markushevich %A Alexander Tikhomirov %X We construct a compactification $M^{\\\\mu ss}$ of the Uhlenbeck-Donaldson type for the moduli space of slope stable framed bundles. This is a kind of a moduli space of slope semistable framed sheaves. We show that there exists a projective morphism $\\\\gamma \\\\colon M^s \\\\to M^{\\\\mu ss}$, where $M^s$ is the moduli space of S-equivalence classes of Gieseker-semistable framed sheaves. The space $M^{\\\\mu ss}$ has a natural set-theoretic stratification which allows one, via a Hitchin-Kobayashi correspondence, to compare it with the moduli spaces of framed ideal instantons. %G en_US %U http://hdl.handle.net/1963/4049 %1 353 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-09-08T08:00:00Z\\nNo. of bitstreams: 1\\nBruzzo59FM.pdf: 496341 bytes, checksum: 3e67e590463152505d393721e3a2c10a (MD5) %0 Journal Article %J Proceedings of the Steklov Institute of Mathematics. Volume 268, Issue 1, 2010, Pages 17-31 %D 2010 %T Well-posed infinite horizon variational problems on a compact manifold %A Andrei Agrachev %X We give an effective sufficient condition for a variational problem with infinite horizon on a compact Riemannian manifold M to admit a smooth optimal synthesis, i. e., a smooth dynamical system on M whose positive semi-trajectories are solutions to the problem. To realize the synthesis, we construct an invariant Lagrangian submanifold (well-projected to M) of the flow of extremals in the cotangent bundle T*M. The construction uses the curvature of the flow in the cotangent bundle and some ideas of hyperbolic dynamics %B Proceedings of the Steklov Institute of Mathematics. Volume 268, Issue 1, 2010, Pages 17-31 %I SISSA %G en %U http://hdl.handle.net/1963/6458 %1 6404 %2 Mathematics %4 1 %# MAT/05 ANALISI MATEMATICA %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-02-05T14:50:56Z\\nNo. of bitstreams: 1\\ndiscount.pdf: 256111 bytes, checksum: 78c64c5edffbe71a9201c6023252b87d (MD5) %R 10.1134/S0081543810010037 %0 Journal Article %J Mem. Differential Equations Math. Phys. 47 (2009) 133-158 %D 2009 %T 1D periodic potentials with gaps vanishing at k=0 %A Alessandro Michelangeli %A Osvaldo Zagordi %X Appearance of energy bands and gaps in the dispersion relations of a periodic potential is a standard feature of Quantum Mechanics. We investigate the class of one-dimensional periodic potentials for which all gaps vanish at the center of the Brillouin zone. We characterise themthrough a necessary and sufficient condition. Potentials of the form we focus on arise in different fields of Physics, from supersymmetric Quantum Mechanics, to Korteweg-de Vries equation theory and classical diffusion problems. The O.D.E. counterpart to this problem is the characterisation of periodic potentials for which coexistence occurs of linearly independent solutions of the corresponding Schrödinger equation (Hill\\\'s equation). This result is placed in the perspective of the previous related results available in the literature. %B Mem. Differential Equations Math. Phys. 47 (2009) 133-158 %G en_US %U http://hdl.handle.net/1963/1818 %1 2396 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-04-18T13:06:21Z\\nNo. of bitstreams: 1\\ncond-mat0603172.pdf: 227250 bytes, checksum: 8b182847d3be1ae07188b40594750f64 (MD5) %0 Book Section %B Encyclopedia of Complexity and Systems Science / Robert A. Meyers (ed.). - Springer, 2009, 548-554 %D 2009 %T Biological Fluid Dynamics, Non-linear Partial Differential Equations %A Antonio DeSimone %A Francois Alouges %A Aline Lefebvre %B Encyclopedia of Complexity and Systems Science / Robert A. Meyers (ed.). - Springer, 2009, 548-554 %G en_US %U http://hdl.handle.net/1963/2630 %1 1493 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-04-16T08:35:02Z\\nNo. of bitstreams: 1\\nEncyclopedia_SISSA_Preprint.pdf: 157119 bytes, checksum: 6db74c2f0a9ba80b7b1e5375bd550c0c (MD5) %0 Journal Article %J Arch. Ration. Mech. Anal. 191 (2009) 1-96 %D 2009 %T The boundary Riemann solver coming from the real vanishing viscosity approximation %A Stefano Bianchini %A Laura Spinolo %X We study the limit of the hyperbolic-parabolic approximation $$ \\\\begin{array}{lll} v_t + \\\\tilde{A} ( v, \\\\, \\\\varepsilon v_x ) v_x = \\\\varepsilon \\\\tilde{B}(v ) v_{xx} \\\\qquad v \\\\in R^N\\\\\\\\ \\\\tilde \\\\beta (v (t, \\\\, 0)) = \\\\bar g \\\\\\\\ v (0, \\\\, x) = \\\\bar v_0. \\\\\\\\ \\\\end{array} \\\\right. $$\\nThe function $\\\\tilde \\\\beta$ is defined in such a way to guarantee that the initial boundary value problem is well posed even if $\\\\tilde \\\\beta$ is not invertible.\\nThe data $\\\\bar g$ and $\\\\bar v_0$ are constant. When $\\\\tilde B$ is invertible, the previous problem takes the simpler form $$ \\\\left\\\\{ \\\\begin{array}{lll} v_t + \\\\tilde{A} \\\\big( v, \\\\, \\\\varepsilon v_x \\\\big) v_x = \\\\varepsilon \\\\tilde{B}(v ) v_{xx} \\\\qquad v \\\\in \\\\mathbb{R}^N\\\\\\\\ v (t, \\\\, 0) \\\\equiv \\\\bar v_b \\\\\\\\ v (0, \\\\, x) \\\\equiv \\\\bar{v}_0. \\\\\\\\ \\\\end{array} \\\\right. $$\\nAgain, the data $\\\\bar v_b$ and $\\\\bar v_0$ are constant. The conservative case is included in the previous formulations. It is assumed convergence of the v, smallness of the total variation and other technical hypotheses and it is provided a complete characterization of the limit. The most interesting points are the following two. First, the boundary characteristic case is considered, i.e. one eigenvalue of $\\\\tilde A$ can be 0.\\n Second, as pointed out before we take into account the possibility that $\\\\tilde B$ is not invertible. To deal with this case, we take as hypotheses conditions that were introduced by Kawashima and Shizuta relying on physically meaningful examples. We also introduce a new condition of block linear degeneracy. We prove that, if it is not satisfied, then pathological behaviours may occur. %B Arch. Ration. Mech. Anal. 191 (2009) 1-96 %G en_US %U http://hdl.handle.net/1963/1831 %1 2385 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-06-08T11:20:08Z\\nNo. of bitstreams: 1\\nmath.AP-0605575.pdf: 716141 bytes, checksum: 7686c7f41f7b1f82a595f668049640f2 (MD5) %R 10.1007/s00205-008-0177-6 %0 Report %D 2009 %T Bubbles with prescribed mean curvature: the variational approach %A Paolo Caldiroli %A Roberta Musina %G en_US %U http://hdl.handle.net/1963/3659 %1 646 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-07-08T13:03:07Z\\nNo. of bitstreams: 1\\nSISSA 35-2009-M.pdf: 294313 bytes, checksum: cf6b1d87612220dc9238502f59175615 (MD5) %0 Journal Article %J BMC Research Notes (2009) 2:13 %D 2009 %T Characterization of the time course of changes of the evoked electrical activity in a model of a chemically-induced neuronal plasticity %A Frederic D. Broccard %A Silvia Pegoraro %A Maria Elisabetta Ruaro %A Claudio Altafini %A Vincent Torre %X BACKGROUND: Neuronal plasticity is initiated by transient elevations of neuronal networks activity leading to changes of synaptic properties and providing the basis for memory and learning 1. An increase of electrical activity can be caused by electrical stimulation 2 or by pharmacological manipulations: elevation of extracellular K+ 3, blockage of inhibitory pathways 4 or by an increase of second messengers intracellular concentrations 5. Neuronal plasticity is mediated by several biochemical pathways leading to the modulation of synaptic strength, density of ionic channels and morphological changes of neuronal arborisation 6. On a time scale of a few minutes, neuronal plasticity is mediated by local protein trafficking 7 while, in order to sustain modifications beyond 2-3 h, changes of gene expression are required 8. FINDINGS: In the present manuscript we analysed the time course of changes of the evoked electrical activity during neuronal plasticity and we correlated it with a transcriptional analysis of the underlying changes of gene expression. Our investigation shows that treatment for 30 min. with the GABAA receptor antagonist gabazine (GabT) causes a potentiation of the evoked electrical activity occurring 2-4 hours after GabT and the concomitant up-regulation of 342 genes. Inhibition of the ERK1/2 pathway reduced but did not abolish the potentiation of the evoked response caused by GabT. In fact not all the genes analysed were blocked by ERK1/2 inhibitors. CONCLUSION: These results are in agreement with the notion that neuronal plasticity is mediated by several distinct pathways working in unison. %B BMC Research Notes (2009) 2:13 %I BioMed Central %G en_US %U http://hdl.handle.net/1963/3706 %1 599 %2 Neuroscience %3 Neurobiology %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-08-12T11:40:38Z\\nNo. of bitstreams: 1\\n1756-0500-2-13.pdf: 518127 bytes, checksum: 0cd264c3567a0d1776a5141b6dc5ef4e (MD5) %R 10.1186/1756-0500-2-13 %0 Journal Article %J Rend. Istit. Mat. Univ. Trieste 41 (2009) 35-41 %D 2009 %T A connection between viscous profiles and singular ODEs %A Stefano Bianchini %A Laura Spinolo %B Rend. Istit. Mat. Univ. Trieste 41 (2009) 35-41 %G en_US %U http://hdl.handle.net/1963/2555 %1 1564 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-01-15T10:38:45Z\\nNo. of bitstreams: 1\\nSissa0508M.pdf: 107079 bytes, checksum: 5af029f1d9bcd4f14be2d8774cfa251e (MD5) %0 Journal Article %J Systems Control Lett. 58 (2009) 213-216 %D 2009 %T Controllability and simultaneous controllability of isospectral bilinear control systems on complex flag manifolds %A Claudio Altafini %X For isospectral bilinear control systems evolving on the so-called complex flag manifolds (i.e., on the orbits of the Hermitian matrices under unitary conjugation action) it is shown that controllability is almost always verified. Easy and generic sufficient conditions are provided. The result applies to the problem of density operator controllability of finite dimensional quantum mechanical systems. In addition, we show that systems having different drifts (corresponding for example to different Larmor frequencies) are simultaneously controllable by the same control field. %B Systems Control Lett. 58 (2009) 213-216 %I Elsevier %G en_US %U http://hdl.handle.net/1963/3523 %1 741 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-02-19T09:39:57Z\\nNo. of bitstreams: 1\\nquens-controll.pdf: 158724 bytes, checksum: 19e7a4ce17acbe97895e145a95916c7a (MD5) %R 10.1016/j.sysconle.2008.10.008 %0 Journal Article %J Ann. Inst. H. Poincare Anal. Non Lineaire 26 (2009) 329-349 %D 2009 %T Controllability of the discrete-spectrum Schrodinger equation driven by an external field %A Thomas Chambrion %A Paolo Mason %A Mario Sigalotti %A Ugo Boscain %X We prove approximate controllability of the bilinear Schrodinger equation in the case in which the uncontrolled Hamiltonian has discrete nonresonant\\nspectrum. The results that are obtained apply both to bounded or unbounded domains and to the case in which the control potential is bounded or unbounded. The method relies on finite-dimensional techniques applied to the\\nGalerkin approximations and permits, in addition, to get some controllability properties for the density matrix. Two examples are presented: the harmonic oscillator and the 3D well of potential controlled by suitable potentials. %B Ann. Inst. H. Poincare Anal. Non Lineaire 26 (2009) 329-349 %G en_US %U http://hdl.handle.net/1963/2547 %1 1572 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-01-10T13:32:19Z\\nNo. of bitstreams: 1\\n2008-ttinger.pdf: 270196 bytes, checksum: e706dbae08d996576cefe55f53d7284e (MD5) %R 10.1016/j.anihpc.2008.05.001 %0 Thesis %D 2009 %T Controllability on the Group of Diffeomorphisms %A Marco Caponigro %I SISSA %G en %U http://hdl.handle.net/1963/5902 %1 5749 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-06-08T09:37:21Z\\nNo. of bitstreams: 1\\nPhD_Caponigro_Marco.pdf: 6237753 bytes, checksum: b44e41275ae3a41def3f0723c81e463e (MD5) %0 Journal Article %J Ann. Inst. H. Poincaré Anal. Non Linéaire 26 (2009) 2503-2509 %D 2009 %T Controllability on the group of diffeomorphisms %A Andrei Agrachev %A Marco Caponigro %X Given a compact manifold M, we prove that any bracket generating family of vector fields on M, which is invariant under multiplication by smooth functions, generates the connected component of identity of the group of diffeomorphisms of M. %B Ann. Inst. H. Poincaré Anal. Non Linéaire 26 (2009) 2503-2509 %G en_US %U http://hdl.handle.net/1963/3396 %1 936 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-12-11T12:06:43Z\\nNo. of bitstreams: 1\\nAgrachev_Caponigro.pdf: 145136 bytes, checksum: 90eebd9912f15c33d1d93f5108ab93aa (MD5) %R 10.1016/j.anihpc.2009.07.003 %0 Journal Article %J Discrete Contin. Dyn. Syst. 23 (2009) 29-48 %D 2009 %T On the convergence of viscous approximations after shock interactions %A Alberto Bressan %A Carlotta Donadello %X We consider a piecewise smooth solution to a scalar conservation law, with possibly interacting shocks. We show that, after the interactions have taken place, vanishing viscosity approximations can still be represented by a regular expansion on smooth regions and by a singular perturbation expansion near the shocks, in terms of powers of the viscosity coefficient. %B Discrete Contin. Dyn. Syst. 23 (2009) 29-48 %I American Institute of Mathematical Sciences %G en_US %U http://hdl.handle.net/1963/3412 %1 923 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-01-09T12:23:11Z\\nNo. of bitstreams: 1\\n019.pdf: 273198 bytes, checksum: 4513df79a27da75ea57c4374c83b0cf6 (MD5) %R 10.3934/dcds.2009.23.29 %0 Journal Article %J JHEP 06 (2009) 046 %D 2009 %T Decoupling A and B model in open string theory: topological adventures in the world of tadpoles %A Giulio Bonelli %A Andrea Prudenziati %A Alessandro Tanzini %A Yang Jie %X In this paper we analyze the problem of tadpole cancellation in open topological strings. We prove that the inclusion of unorientable worldsheet diagrams guarantees a consistent decoupling of A and B model for open superstring amplitudes at all genera. This is proven by direct microscopic computation in Super Conformal Field Theory. For the B-model we explicitly calculate one loop amplitudes in terms of analytic Ray-Singer torsions of appropriate vector bundles and obtain that the decoupling corresponds to the cancellation of D-brane and orientifold charges. Local tadpole cancellation on the worldsheet then guarantees the decoupling at all loops. The holomorphic anomaly equations for open topological strings at one loop are also obtained and compared with the results of the Quillen formula. %B JHEP 06 (2009) 046 %G en_US %U http://hdl.handle.net/1963/3632 %1 672 %2 Physics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-05-14T12:10:45Z\\nNo. of bitstreams: 1\\n0905.1286v1.pdf: 335944 bytes, checksum: fe5d3723cd904f1c7123c5bc83356013 (MD5) %R 10.1088/1126-6708/2009/06/046 %0 Journal Article %J Differential Geom. Appl. 27 (2009) 723-742 %D 2009 %T Differential geometry of curves in Lagrange Grassmannians with given Young diagram %A Igor Zelenko %A Li Chengbo %X Curves in Lagrange Grassmannians appear naturally in the intrinsic study of geometric structures on manifolds. By a smooth geometric structure on a manifold we mean any submanifold of its tangent bundle, transversal to the fibers. One can consider the time-optimal problem naturally associate with a geometric structure. The Pontryagin extremals of this optimal problem are integral curves of certain Hamiltonian system in the cotangent bundle. The dynamics of the fibers of the cotangent bundle w.r.t. this system along an extremal is described by certain curve in a Lagrange Grassmannian, called Jacobi curve of the extremal. Any symplectic invariant of the Jacobi curves produces the invariant of the original geometric structure. The basic characteristic of a curve in a Lagrange Grassmannian is its Young diagram. The number of boxes in its kth column is equal to the rank of the kth derivative of the curve (which is an appropriately defined linear mapping) at a generic point. We will describe the construction of the complete system of symplectic invariants for parameterized curves in a Lagrange Grassmannian with given Young diagram. It allows to develop in a unified way local differential geometry of very wide classes of geometric structures on manifolds, including both classical geometric structures such as Riemannian and Finslerian structures and less classical ones such as sub-Riemannian and sub-Finslerian structures, defined on nonholonomic distributions. %B Differential Geom. Appl. 27 (2009) 723-742 %I Elsevier %G en_US %U http://hdl.handle.net/1963/3819 %1 508 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-01-18T16:06:20Z\\nNo. of bitstreams: 1\\n0708.1100v1.pdf: 330722 bytes, checksum: 31be09831ca0758a658e2fc9fe6a900f (MD5) %R 10.1016/j.difgeo.2009.07.002 %0 Journal Article %J Netw. Heterog. Media 4 (2009) 667-708 %D 2009 %T Discrete-to-continuum limits for strain-alignment-coupled systems: Magnetostrictive solids, ferroelectric crystals and nematic elastomers %A Marco Cicalese %A Antonio DeSimone %A Caterina Ida Zeppieri %X In the framework of linear elasticity, we study the limit of a class of discrete free energies modeling strain-alignment-coupled systems by a rigorous coarse-graining procedure, as the number of molecules diverges. We focus on three paradigmatic examples: magnetostrictive solids, ferroelectric crystals and nematic elastomers, obtaining in the limit three continuum models consistent with those commonly employed in the current literature. We also derive the correspondent macroscopic energies in the presence of displacement boundary conditions and of various kinds of applied external fields. %B Netw. Heterog. Media 4 (2009) 667-708 %I American Institute of Mathematical Sciences %G en_US %U http://hdl.handle.net/1963/3788 %1 538 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-11-25T10:31:11Z\\nNo. of bitstreams: 1\\nCDSZ08.pdf: 390765 bytes, checksum: 2b3fcd3668352c286200e0a3b7e12c1a (MD5) %R 10.3934/nhm.2009.4.667 %0 Thesis %D 2009 %T The Disintegration Theorem and Applications to Optimal Mass Transportation %A Laura Caravenna %I SISSA %G en %U http://hdl.handle.net/1963/5900 %1 5750 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-06-08T09:44:06Z\\nNo. of bitstreams: 1\\nPhDThesisCaravenna.pdf: 1700326 bytes, checksum: 9638dd5ad25fc3e1fb91399b1b12c293 (MD5) %0 Journal Article %J Funct. Anal. Appl. 43 (2009) 18-29 %D 2009 %T Equivariant cohomology and localization for Lie algebroids %A Ugo Bruzzo %A Lucio Cirio %A Paolo Rossi %A Volodya Rubtsov %X Let M be a manifold carrying the action of a Lie group G, and A a Lie algebroid on M equipped with a compatible infinitesimal G-action. Out of these data we construct an equivariant Lie algebroid cohomology and prove for compact G a related localization formula. As an application we prove a Bott-type formula. %B Funct. Anal. Appl. 43 (2009) 18-29 %@ 978-981-270-377-4 %G en_US %U http://hdl.handle.net/1963/1724 %1 2427 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-01-26T15:10:18Z\\nNo. of bitstreams: 1\\nmathDG0506392.pdf: 223181 bytes, checksum: bb9437e12cfd3d7cc5c14904aaeebe7d (MD5) %R 10.1007/s10688-009-0003-4 %0 Journal Article %J Bioinformatics 25 (2009) 2853-2854 %D 2009 %T ERNEST: a toolbox for chemical reaction network theory %A Nicola Soranzo %A Claudio Altafini %X Summary: ERNEST Reaction Network Equilibria Study Toolbox is a MATLAB package which, by checking various different criteria on the structure of a chemical reaction network, can exclude the multistationarity of the corresponding reaction system. The results obtained are independent of the rate constants of the reactions, and can be used for model discrimination.\\nAvailability and Implementation: The software, implemented in MATLAB, is available under the GNU GPL free software license from http://people.sissa.it/~altafini/papers/SoAl09/. It requires the MATLAB Optimization Toolbox. %B Bioinformatics 25 (2009) 2853-2854 %I Oxford University Press %G en_US %U http://hdl.handle.net/1963/3826 %1 501 %2 Physics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-01-22T11:56:56Z\\nNo. of bitstreams: 1\\nSoAl09.pdf: 30345 bytes, checksum: a3c73c1a74eb623da69be9a9eba3ca72 (MD5) %R 10.1093/bioinformatics/btp513 %0 Journal Article %J Comm. Math. Phys. 289 (2009) 205-252 %D 2009 %T Exact results for topological strings on resolved Yp,q singularities %A Andrea Brini %A Alessandro Tanzini %B Comm. Math. Phys. 289 (2009) 205-252 %G en_US %U http://hdl.handle.net/1963/2631 %1 1492 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-04-16T11:13:40Z\\nNo. of bitstreams: 1\\npicard-b.pdf: 387933 bytes, checksum: 2261a0d091c9829eb1d1b55b77b1a42e (MD5) %R 10.1007/s00220-009-0814-4 %0 Journal Article %J Nonlinear Anal. 70 (2009) 3002-3007 %D 2009 %T Existence of extremals for the Maz\\\'ya and for the Caffarelli-Kohn-Nirenberg inequalities %A Roberta Musina %X This paper deals with some Sobolev-type inequalities with weights that were proved by Maz\\\'ya in 1980 and by Caffarelli-Kohn-Nirenberg in 1984. %B Nonlinear Anal. 70 (2009) 3002-3007 %G en_US %U http://hdl.handle.net/1963/2739 %1 1961 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-08-27T08:18:23Z\\nNo. of bitstreams: 1\\nMusinaCortona2.pdf: 220927 bytes, checksum: aeec20cde67e9e00bc1109988f192159 (MD5) %R 10.1016/j.na.2008.12.024 %0 Report %D 2009 %T An existence result for the Monge problem in R^n with norm cost %A Laura Caravenna %G en_US %U http://hdl.handle.net/1963/3647 %1 657 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-06-10T13:31:00Z\\nNo. of bitstreams: 1\\nMonge.sel.pdf: 1037029 bytes, checksum: 3f852fb5f7d74223ddee50818368c3f5 (MD5) %0 Journal Article %J Bull. Inst. Math. Acad. Sin. (N.S.) 4 (2009) 353-458 %D 2009 %T On the extremality, uniqueness and optimality of transference plans %A Stefano Bianchini %A Laura Caravenna %X We consider the following standard problems appearing in optimal mass transportation theory: when a transference plan is extremal; when a transference plan is the unique transference plan concentrated on a set A,; when a transference plan is optimal. %B Bull. Inst. Math. Acad. Sin. (N.S.) 4 (2009) 353-458 %G en_US %U http://hdl.handle.net/1963/3692 %1 613 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-07-24T11:10:18Z\\nNo. of bitstreams: 1\\n46M2009.pdf: 485239 bytes, checksum: ebe15dc163dd6bdffcbe875730432b12 (MD5) %0 Report %D 2009 %T Families of Monads and Instantons from a Noncommutative ADHM Construction %A Simon Brain %A Giovanni Landi %X We give a \\\\theta-deformed version of the ADHM construction of SU(2) instantons with arbitrary topological charge on the sphere S^4. Classically the instanton gauge fields are constructed from suitable monad data; we show that in the deformed case the set of monads is itself a noncommutative space. We use these monads to construct noncommutative `families\\\' of SU(2) instantons on the deformed sphere S^4_\\\\theta. We also compute the topological charge of each of the families. Finally we discuss what it means for such families to be gauge equivalent. %G en_US %U http://hdl.handle.net/1963/3478 %1 786 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-02-03T16:03:42Z\\nNo. of bitstreams: 1\\nBrain_Landi.pdf: 343656 bytes, checksum: 7d0ea754b63fce4b2a83db6423e67650 (MD5) %0 Journal Article %J Comm. Math. Phys. 287 (2009) 179-209 %D 2009 %T Gauged Laplacians on quantum Hopf bundles %A Giovanni Landi %A Cesare Reina %A Alessandro Zampini %X We study gauged Laplacian operators on line bundles on a quantum 2-dimensional sphere. Symmetry under the (co)-action of a quantum group allows for their complete diagonalization. These operators describe `excitations moving on the quantum sphere\\\' in the field of a magnetic monopole. The energies are not invariant under the exchange monopole/antimonopole, that is under inverting the direction of the magnetic field. There are potential applications to models of quantum Hall effect. %B Comm. Math. Phys. 287 (2009) 179-209 %I Springer %G en_US %U http://hdl.handle.net/1963/3540 %1 1161 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-02-24T09:35:24Z\\nNo. of bitstreams: 1\\n0801.3376v2.pdf: 353792 bytes, checksum: 1153ca993428f38ef95f7d31cd727743 (MD5) %R 10.1007/s00220-008-0672-5 %0 Book Section %B New Trends in Mathematical Physics : Selected contributions of the XVth International Congress on Mathematical Physics, Springer Netherlands, 2009, pp. 231-276. %D 2009 %T Hamiltonian perturbations of hyperbolic PDEs: from classification results to the properties of solutions %A Boris Dubrovin %X We begin with presentation of classi cation results in the theory of Hamiltonian\\r\\nPDEs with one spatial dimension depending on a small parameter. Special\\r\\nattention is paid to the deformation theory of integrable hierarchies, including an\\r\\nimportant subclass of the so-called integrable hierarchies of the topological type\\r\\nassociated with semisimple Frobenius manifolds. Many well known equations of\\r\\nmathematical physics, such as KdV, NLS, Toda, Boussinesq etc., belong to this\\r\\nsubclass, but there are many new integrable PDEs, some of them being of interest\\r\\nfor applications. Connections with the theory of Gromov{Witten invariants\\r\\nand random matrices are outlined. We then address the problem of comparative\\r\\nstudy of singularities of solutions to the systems of first order quasilinear\\r\\nPDEs and their Hamiltonian perturbations containing higher derivatives. We\\r\\nformulate Universality Conjectures describing different types of critical behavior\\r\\nof perturbed solutions near the point of gradient catastrophe of the unperturbed\\r\\none. %B New Trends in Mathematical Physics : Selected contributions of the XVth International Congress on Mathematical Physics, Springer Netherlands, 2009, pp. 231-276. %I SISSA %@ 978-90-481-2810-5 %G en %U http://hdl.handle.net/1963/6470 %1 6415 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Boris Dubrovin (dubrovin@sissa.it) on 2013-02-11T14:43:17Z\\nNo. of bitstreams: 1\\ndubrovin_icmp.pdf: 902220 bytes, checksum: a35a8999aa1c5c58113eda66180935d9 (MD5) %0 Journal Article %J Commun. Contemp. Math. 11 (2009) 993-1007 %D 2009 %T Hardy-Sobolev-Maz\\\'ja inequalities: symmetry and breaking symmetry of extremal functions %A Marita Gazzini %A Roberta Musina %B Commun. Contemp. Math. 11 (2009) 993-1007 %G en_US %U http://hdl.handle.net/1963/2569 %1 1551 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-01-21T11:13:29Z\\nNo. of bitstreams: 1\\nGaMu2.pdf: 291392 bytes, checksum: 026cb4fccae5ac75b171e8a2923b84ca (MD5) %R 10.1142/S0219199709003636 %0 Journal Article %J SIAM J. Math. Anal. 40 (2009) 2351-2391 %D 2009 %T A higher order model for image restoration: the one dimensional case %A Gianni Dal Maso %A Irene Fonseca %A Giovanni Leoni %A Massimiliano Morini %X The higher order total variation-based model for image restoration proposed by Chan, Marquina, and Mulet in [6] is analyzed in one dimension. A suitable functional framework in which the minimization problem is well posed is being proposed and it is proved analytically that the\\nhigher order regularizing term prevents the occurrence of the staircase effect. The generalized version of the model considered here includes, as particular cases, some curvature dependent functionals. %B SIAM J. Math. Anal. 40 (2009) 2351-2391 %G en_US %U http://hdl.handle.net/1963/3174 %1 1127 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-10-23T07:52:52Z\\nNo. of bitstreams: 1\\nDM-Fon-Leo-Mor-08-preprint.pdf: 336946 bytes, checksum: 32db893a2b928f559b6744296e1d4f2c (MD5) %R 10.1137/070697823 %0 Report %D 2009 %T Holomorphic equivariant cohomology of Atiyah algebroids and localization %A Ugo Bruzzo %A Vladimir Rubtsov %G en_US %U http://hdl.handle.net/1963/3774 %1 551 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-10-12T13:02:22Z\\nNo. of bitstreams: 1\\n65_2009_FM.pdf: 196675 bytes, checksum: 14f333a384c90c27709c53dafc98127b (MD5) %0 Journal Article %J SIAM J. Math. Anal. 41 (2009) 1874-1889 %D 2009 %T Homogenization of fiber reinforced brittle materials: the extremal cases %A Marco Barchiesi %A Gianni Dal Maso %X We analyze the behavior of a fragile material reinforced by a reticulated elastic unbreakable structure in the case of antiplane shear. The microscopic geometry of this material is described by means of two small parameters: the period $\\\\varepsilon$ of the grid and the ratio $\\\\delta$ between the thickness of the fibers and the period $\\\\varepsilon$. We show that the asymptotic behavior as $\\\\varepsilon\\\\to0^+$ and $\\\\delta\\\\to0^+$ depends dramatically on the relative size of these parameters. Indeed, in the two cases considered, i.e., $\\\\varepsilon\\\\ll\\\\delta$ and $\\\\varepsilon\\\\gg\\\\delta$, we obtain two different limit models: a perfectly elastic model and an elastic model with macroscopic cracks, respectively. %B SIAM J. Math. Anal. 41 (2009) 1874-1889 %I SIAM %G en_US %U http://hdl.handle.net/1963/2705 %1 1396 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-08-13T12:57:01Z\\nNo. of bitstreams: 1\\nmicrofibre.pdf: 236545 bytes, checksum: 53ef9ce789d27bba7dcac550930f306b (MD5) %0 Journal Article %J Physica D 238 (2009) 55-66 %D 2009 %T Initial value problem of the Whitham equations for the Camassa-Holm equation %A Tamara Grava %A Virgil U. Pierce %A Fei-Ran Tian %X We study the Whitham equations for the Camassa-Holm equation. The equations are neither strictly hyperbolic nor genuinely nonlinear. We are interested in the initial value problem of the Whitham equations. When the initial values are given by a step function, the Whitham solution is self-similar. When the initial values are given by a smooth function, the Whitham solution exists within a cusp in the x-t plane. On the boundary of the cusp, the Whitham equation matches the Burgers solution, which exists outside the cusp. %B Physica D 238 (2009) 55-66 %I Elsevier %G en_US %U http://hdl.handle.net/1963/3429 %1 906 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-01-13T13:01:16Z\\nNo. of bitstreams: 1\\n0805.2558v1.pdf: 498872 bytes, checksum: 4d721f99d6ae9840be2332f3cc6a4118 (MD5) %R 10.1016/j.physd.2008.08.016 %0 Journal Article %J J. Funct. Anal. 256 (2009) 2621-2655 %D 2009 %T The intrinsic hypoelliptic Laplacian and its heat kernel on unimodular Lie groups %A Andrei Agrachev %A Ugo Boscain %A Jean-Paul Gauthier %A Francesco Rossi %X We present an invariant definition of the hypoelliptic Laplacian on sub-Riemannian structures with constant growth vector, using the Popp\\\'s volume form introduced by Montgomery. This definition generalizes the one of the Laplace-Beltrami operator in Riemannian geometry. In the case of left-invariant problems on unimodular Lie groups we prove that it coincides with the usual sum of squares.\\nWe then extend a method (first used by Hulanicki on the Heisenberg group) to compute explicitly the kernel of the hypoelliptic heat equation on any unimodular Lie group of type I. The main tool is the noncommutative Fourier transform. We then study some relevant cases: SU(2), SO(3), SL(2) (with the metrics inherited by the Killing form), and the group SE(2) of rototranslations of the plane.\\nOur study is motivated by some recent results about the cut and conjugate loci on these sub-Riemannian manifolds. The perspective is to understand how singularities of the sub-Riemannian distance reflect on the kernel of the corresponding hypoelliptic heat equation. %B J. Funct. Anal. 256 (2009) 2621-2655 %G en_US %U http://hdl.handle.net/1963/2669 %1 1428 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-06-11T11:38:01Z\\nNo. of bitstreams: 1\\n0806.0734v1.pdf: 494960 bytes, checksum: 640ace795ac663f09426814440b15432 (MD5) %R 10.1016/j.jfa.2009.01.006 %0 Journal Article %J PLoS Comput Biol 2009;5(7): e1000420 %D 2009 %T Investigating the Conformational Stability of Prion Strains through a Kinetic Replication Model %A Mattia Zampieri %A Giuseppe Legname %A Claudio Altafini %X Prion proteins are known to misfold into a range of different aggregated forms, showing different phenotypic and pathological states. Understanding strain specificities is an important problem in the field of prion disease. Little is known about which PrPSc structural properties and molecular mechanisms determine prion replication, disease progression and strain phenotype. The aim of this work is to investigate, through a mathematical model, how the structural stability of different aggregated forms can influence the kinetics of prion replication. The model-based results suggest that prion strains with different conformational stability undergoing in vivo replication are characterizable in primis by means of different rates of breakage. A further role seems to be played by the aggregation rate (i.e. the rate at which a prion fibril grows). The kinetic variability introduced in the model by these two parameters allows us to reproduce the different characteristic features of the various strains (e.g., fibrils\\\' mean length) and is coherent with all experimental observations concerning strain-specific behavior. %B PLoS Comput Biol 2009;5(7): e1000420 %I PLoS %G en_US %U http://hdl.handle.net/1963/3989 %1 413 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-08-11T10:35:47Z\\nNo. of bitstreams: 1\\njournal.pcbi.1000420.pdf: 468491 bytes, checksum: fda67b47ac16d98d11bc4ac879c17ec0 (MD5) %R 10.1371/journal.pcbi.1000420 %0 Report %D 2009 %T Jacobi Equations and Comparison Theorems for Corank 1 Sub-Riemannian structures with symmetries %A Li Chengbo %A Igor Zelenko %X The Jacobi curve of an extremal of optimal control problem is a curve in a Lagrangian Grassmannian defined up to a symplectic transformation and containing all information about the solutions of the Jacobi equations along this extremal. In our previous works we constructed the canonical\\nbundle of moving frames and the complete system of symplectic invariants, called curvature maps, for\\nparametrized curves in Lagrange Grassmannians satisfying very general assumptions. The structural\\nequation for a canonical moving frame of the Jacobi curve of an extremal can be interpreted as the\\nnormal form for the Jacobi equation along this extremal and the curvature maps can be seen as the\\n\\\"coefficients\\\"of this normal form. In the case of a Riemannian metric there is only one curvature map and it is naturally related to the Riemannian sectional curvature. In the present paper we study the curvature maps for a sub-Riemannian structure on a corank 1 distribution having an additional transversal infinitesimal symmetry. After the factorization by the integral foliation of this symmetry, such sub-Riemannian structure can be reduced to a Riemannian manifold equipped with a closed 2-form(a magnetic field). We obtain explicit expressions for the curvature maps of the original sub-Riemannian structure in terms of the curvature tensor of this Riemannian manifold and the magnetic field. We also estimate the number of conjugate points along the sub-Riemannian extremals in terms of the bounds for the curvature tensor of this Riemannian manifold and the magnetic field in the case of an uniform magnetic field. The language developed for the calculation of the curvature maps can be applied to more general sub-Riemannian structures with symmetries, including sub-Riemmannian structures appearing naturally in Yang-Mills fields. %G en_US %U http://hdl.handle.net/1963/3736 %1 581 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-09-08T13:36:18Z\\nNo. of bitstreams: 1\\njacompfin.pdf: 329060 bytes, checksum: 48bb88c074e19b86902a553f2055ddea (MD5) %0 Journal Article %J Journal of Structural Engineering %D 2009 %T Low-Frequency Variations of Force Coefficients on Square Cylinders with Sharp and Rounded Corners %A Andrea Mola %A Giancarlo Bordonaro %A Muhammad R. Hajj %B Journal of Structural Engineering %I American Society of Civil Engineers ({ASCE}) %V 135 %P 828–835 %8 jul %G eng %U https://doi.org/10.1061/(asce)st.1943-541x.0000034 %R 10.1061/(asce)st.1943-541x.0000034 %0 Journal Article %J International Journal for Numerical Methods in Fluids %D 2009 %T A model for the dynamics of rowing boats %A Luca Formaggia %A Edie Miglio %A Andrea Mola %A Antonio Montano %B International Journal for Numerical Methods in Fluids %I Wiley %V 61 %P 119–143 %8 sep %G eng %U https://doi.org/10.1002/fld.1940 %R 10.1002/fld.1940 %0 Journal Article %J Comm. Algebra 37 (2009) 503-514 %D 2009 %T A model for the orbifold Chow ring of weighted projective spaces %A Samuel Boissiere %A Etienne Mann %A Fabio Perroni %X We construct an isomorphism of graded Frobenius algebras between the orbifold Chow ring of weighted projective spaces and graded algebras of groups of roots of the unity. %B Comm. Algebra 37 (2009) 503-514 %I Taylor and Francis %G en_US %U http://hdl.handle.net/1963/3589 %1 711 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-03-09T14:26:00Z\\nNo. of bitstreams: 1\\n0709.4559v1.pdf: 182412 bytes, checksum: d6f5ea45f21c8eb995d417277fa544d4 (MD5) %R 10.1080/00927870802248902 %0 Report %D 2009 %T The Monge problem for distance cost in geodesic spaces %A Stefano Bianchini %A Fabio Cavalletti %G en_US %U http://hdl.handle.net/1963/3703 %1 602 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-08-06T14:18:58Z\\nNo. of bitstreams: 1\\nmongemetric.pdf: 347506 bytes, checksum: 1ef13dce09da23c1ca9842fec67a0f7f (MD5) %0 Journal Article %J BMC Systems Biology (2009) 3:18 %D 2009 %T mRNA stability and the unfolding of gene expression in the long-period yeast metabolic cycle %A Nicola Soranzo %A Mattia Zampieri %A Lorenzo Farina %A Claudio Altafini %X Background: In yeast, genome-wide periodic patterns associated with energy-metabolic oscillations have been shown recently for both short (approx. 40 min) and long (approx. 300 min) periods.\\nResults: The dynamical regulation due to mRNA stability is found to be an important aspect of the genome-wide coordination of the long-period yeast metabolic cycle. It is shown that for periodic genes, arranged in classes according either to expression profile or to function, the pulses of mRNA abundance have phase and width which are directly proportional to the corresponding turnover rates.\\nConclusion: The cascade of events occurring during the yeast metabolic cycle (and their correlation with mRNA turnover) reflects to a large extent the gene expression program observable in other dynamical contexts such as the response to stresses/stimuli. %B BMC Systems Biology (2009) 3:18 %I BioMed Central %G en_US %U http://hdl.handle.net/1963/3630 %1 674 %2 Physics %3 Statistical and Biological Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-05-07T10:19:22Z\\nNo. of bitstreams: 1\\n1752-0509-3-18.pdf: 1143957 bytes, checksum: 3f6f6d33e3da5ee922c0a2c47af61560 (MD5) %R 10.1186/1752-0509-3-18 %0 Journal Article %J C. R. Math. 347 (2009) 211-216 %D 2009 %T A nonlinear theory for shells with slowly varying thickness %A Marta Lewicka %A Maria Giovanna Mora %A Mohammad Reza Pakzad %X We study the Γ-limit of 3d nonlinear elasticity for shells of small, variable thickness, around an arbitrary smooth 2d surface. %B C. R. Math. 347 (2009) 211-216 %G en_US %U http://hdl.handle.net/1963/2632 %1 1491 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-04-17T10:05:31Z\\nNo. of bitstreams: 1\\nLew-Mor-Pak-08.pdf: 159399 bytes, checksum: a9f5009829a4633482d74870c6fd22b6 (MD5) %R 10.1016/j.crma.2008.12.017 %0 Journal Article %J J. Funct. Anal. 256 (2009) 2741-2745 %D 2009 %T A note on the paper \\\"Optimizing improved Hardy inequalities\\\" by S. Filippas and A. Tertikas %A Roberta Musina %B J. Funct. Anal. 256 (2009) 2741-2745 %G en_US %U http://hdl.handle.net/1963/2698 %1 1402 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-07-25T14:46:48Z\\nNo. of bitstreams: 1\\nMusina_FiTe.pdf: 141073 bytes, checksum: 84d3efccc14d223256f9971f03942f4e (MD5) %R 10.1016/j.jfa.2008.08.009 %0 Journal Article %J Trans. Amer. Math. Soc. 361 (2009) 6019-6047 %D 2009 %T Optimal transportation under nonholonomic constraints %A Andrei Agrachev %A Paul Lee %X We study the Monge\\\'s optimal transportation problem where the cost is given by optimal control cost. We prove the existence and uniqueness of optimal map under certain regularity conditions on the Lagrangian, absolute continuity of the measures and most importantly the absent of sharp abnormal minimizers. In particular, this result is applicable in the case of subriemannian manifolds with a 2-generating distribution and cost given by d2, where d is the subriemannian distance. Also, we discuss some properties of the optimal plan when abnormal minimizers are present. Finally, we consider some examples of displacement interpolation in the case of Grushin plane. %B Trans. Amer. Math. Soc. 361 (2009) 6019-6047 %G en_US %U http://hdl.handle.net/1963/2176 %1 2068 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-04T08:42:08Z\\nNo. of bitstreams: 1\\ntransportpre.pdf: 448316 bytes, checksum: 815a3d8cd33b8f3ea07264062b59ec46 (MD5) %R 10.1090/S0002-9947-09-04813-2 %0 Journal Article %J Math. Models Methods Appl. Sci. 19 (2009) 1643-1711 %D 2009 %T Quasistatic evolution for Cam-Clay plasticity: examples of spatially homogeneous solutions %A Gianni Dal Maso %A Antonio DeSimone %X We study a quasistatic evolution problem for Cam-Clay plasticity under a special loading program which leads to spatially homogeneous solutions. Under some initial conditions, the solutions exhibit a softening behaviour and time discontinuities.\\nThe behavior of the solutions at the jump times is studied by a viscous approximation. %B Math. Models Methods Appl. Sci. 19 (2009) 1643-1711 %G en_US %U http://hdl.handle.net/1963/3395 %1 937 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-12-10T11:56:05Z\\nNo. of bitstreams: 1\\nDal_Maso-DeSimone.pdf: 1160572 bytes, checksum: fd49c80a369183f1941b0fcf3cd65341 (MD5) %R 10.1142/S0218202509003942 %0 Journal Article %J Phys. Rev. E 79 (2009) 031915 %D 2009 %T Relaxation dynamics of fluid membranes %A Marino Arroyo %A Antonio DeSimone %X We study the effect of membrane viscosity in the dynamics of liquid membranes-possibly with free or internal boundaries-driven by conservative forces (curvature elasticity and line tension) and dragged by the bulk dissipation of the ambient fluid and the friction occurring when the amphiphilic molecules move relative to each other. To this end, we formulate a continuum model which includes a form of the governing equations for a two-dimensional viscous fluid moving on a curved, time-evolving surface. The effect of membrane viscosity has received very limited attention in previous continuum studies of the dynamics of fluid membranes, although recent coarse-grained discrete simulations suggest its importance. By applying our model to the study of vesiculation and membrane fusion in a simplified geometry, we conclude that membrane viscosity plays a dominant role in the relaxation dynamics of fluid membranes of sizes comparable to those found in eukaryotic cells, and is not negligible in many large synthetic systems of current interest. %B Phys. Rev. E 79 (2009) 031915 %I American Physical Society %G en_US %U http://hdl.handle.net/1963/3618 %1 686 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-04-22T08:29:29Z\\nNo. of bitstreams: 1\\nmembrane_dynamics_PRE_2.pdf: 1000677 bytes, checksum: e7ab0f6e2046800e154d399808ea314c (MD5) %R 10.1103/PhysRevE.79.031915 %0 Journal Article %J J. Math. Anal. Appl. 352 (2009) 99-111 %D 2009 %T On a Sobolev type inequality related to the weighted p-Laplace operator %A Marita Gazzini %A Roberta Musina %B J. Math. Anal. Appl. 352 (2009) 99-111 %G en_US %U http://hdl.handle.net/1963/2613 %1 1510 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-04-03T10:13:10Z\\nNo. of bitstreams: 1\\nGaMu3.pdf: 298467 bytes, checksum: 6de8ed2f5202430d4c5b002c5f613347 (MD5) %R 10.1016/j.jmaa.2008.06.021 %0 Journal Article %J Adv. Math. 221 (2009) 1843-1909 %D 2009 %T Some new entire solutions of semilinear elliptic equations on Rn %A Andrea Malchiodi %B Adv. Math. 221 (2009) 1843-1909 %I Elsevier %G en_US %U http://hdl.handle.net/1963/3645 %1 659 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-06-08T15:11:59Z\\nNo. of bitstreams: 1\\nentire.pdf: 478191 bytes, checksum: 1b7ea59917a621bf7b2793f7228fade6 (MD5) %R 10.1016/j.aim.2009.03.012 %0 Journal Article %J Math. Models Methods Appl. Sci. 19 (2009) 601-630 %D 2009 %T Strain-order coupling in nematic elastomers: equilibrium configurations %A Pierluigi Cesana %A Antonio DeSimone %X We consider models that describe liquid crystal elastomers either in a biaxial or in a uniaxial phase and in the framework of Frank\\\'s director theory. We prove existence of static equilibrium solutions in the presence of frustrations due to electro-mechanical boundary conditions and to applied loads and fields. We find explicit solutions arising in connection with special boundary conditions and the corresponding phase diagrams, leading to significant implications on possible experimental observations. %B Math. Models Methods Appl. Sci. 19 (2009) 601-630 %G en_US %U http://hdl.handle.net/1963/2700 %1 1400 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-07-25T15:04:59Z\\nNo. of bitstreams: 1\\nprprCdS.pdf: 504721 bytes, checksum: 2ef9aff006dbc9353a50a122cb98d381 (MD5) %0 Report %D 2009 %T Stratos: a code for 3D free surface flows with floating constraints %A Antonio DeSimone %A B. Bianchi %A Luca Heltai %X This report presents a brief discussion of the theoretical aspects and practical implementation of STRATOS . STRATOS is a 3D code for the simulation\\nof hydrodynamic flows for incompressible fluids, in the presence of a free surface, capable of simulating the interaction between the free surface and a\\nfloating object via Lagrange multipliers...... %G en_US %U http://hdl.handle.net/1963/3701 %1 604 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-07-30T14:37:01Z\\nNo. of bitstreams: 1\\nBianchiDeSimoneHeltai.pdf: 899803 bytes, checksum: aff44eb1a39c6fd4acd4b3cb285e2d64 (MD5) %0 Journal Article %J Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology %D 2009 %T A three-dimensional model for the dynamics and hydrodynamics of rowing boats %A L Formaggia %A A Mola %A N Parolini %A M Pischiutta %B Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology %I {SAGE} Publications %V 224 %P 51–61 %8 sep %G eng %U https://doi.org/10.1243/17543371jset46 %R 10.1243/17543371jset46 %0 Report %D 2009 %T Tools for the Solution of PDEs Defined on Curved Manifolds with deal.II %A Antonio DeSimone %A Luca Heltai %A Cataldo Manigrasso %X The deal.II finite element library was originally designed to solve partial differential equations defined on one, two or three space dimensions, mostly\\nvia the Finite Element Method. In its versions prior to version 6.2, the user could not solve problems defined on curved manifolds embedded in two or\\nthree spacial dimensions. This infrastructure is needed if one wants to solve, for example, Boundary Integral Equations. %G en_US %U http://hdl.handle.net/1963/3700 %1 605 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-07-30T14:20:01Z\\nNo. of bitstreams: 1\\nDeSimoneHeltaiManigrasso.pdf: 915137 bytes, checksum: c3144348b6aab67a5f547060049c7847 (MD5) %0 Journal Article %J Phys. Lett. B 672 (2009) 390-395 %D 2009 %T Topological branes, p-algebras and generalized Nahm equations %A Giulio Bonelli %A Alessandro Tanzini %A Maxim Zabzine %X Inspired by the recent advances in multiple M2-brane theory, we consider the generalizations of Nahm equations for arbitrary p-algebras. We construct the topological p-algebra quantum mechanics associated to them and we show that this can be obtained as a truncation of the topological p-brane theory previously studied by the authors. The resulting topological p-algebra quantum mechanics is discussed in detail and the relation with the M2-M5 system is pointed out in the p=3 case, providing a geometrical argument for the emergence of the 3-algebra structure in the Bagger-Lambert-Gustavsson theory %B Phys. Lett. B 672 (2009) 390-395 %G en_US %U http://hdl.handle.net/1963/2702 %1 1398 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-08-08T15:57:12Z\\nNo. of bitstreams: 1\\n0807.5113v1.pdf: 246583 bytes, checksum: 0013b3623fd81d20db0fb541bd4b9dd4 (MD5) %R 10.1016/j.physletb.2009.01.051 %0 Report %D 2009 %T Twisted Covariance vs Weyl Quantisation %A Gherardo Piacitelli %X In this letter we wish to clarify in which sense the tensor nature of the commutation relations [x^mu,x^nu]=i theta ^{mu nu} underlying Minkowski spacetime quantisation cannot be suppressed even in the twisted approach to Lorentz covariance. We then address the vexata quaestio \\\"why theta\\\"? %G en_US %U http://hdl.handle.net/1963/3451 %1 885 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-01-22T12:32:38Z\\nNo. of bitstreams: 1\\nPiacitelli.pdf: 135129 bytes, checksum: 0751d3833fe1a1ab81e7e9b223dcc2e5 (MD5) %0 Journal Article %D 2009 %T Two-dimensional almost-Riemannian structures with tangency points %A Andrei Agrachev %A Ugo Boscain %A Mario Sigalotti %A Roberta Ghezzi %A Grégoire Charlot %X Two-dimensional almost-Riemannian structures are generalized Riemannian\r\nstructures on surfaces for which a local orthonormal frame is given by a Lie\r\nbracket generating pair of vector ?elds that can become collinear. We study the\r\nrelation between the topological invariants of an almost-Riemannian structure\r\non a compact oriented surface and the rank-two vector bundle over the surface\r\nwhich de?nes the structure. We analyse the generic case including the presence\r\nof tangency points, i.e. points where two generators of the distribution and\r\ntheir Lie bracket are linearly dependent. The main result of the paper provides\r\na classi?cation of oriented almost-Riemannian structures on compact oriented\r\nsurfaces in terms of the Euler number of the vector bundle corresponding to the\r\nstructure. Moreover, we present a Gauss?Bonnet formula for almost-Riemannian\r\nstructures with tangency points. %I SISSA %G en %U http://hdl.handle.net/1963/6463 %1 6406 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Andrei Agrachev (agrachev@sissa.it) on 2013-02-05T15:00:41Z\r\nNo. of bitstreams: 1\r\n0908.2564v1.pdf: 302590 bytes, checksum: 15369151ee10bb886dc6678350dee7f5 (MD5) %R 10.1016/j.anihpc.2009.11.011 %0 Journal Article %J J. Nonlinear Sci. 19 (2009) 57-94 %D 2009 %T On universality of critical behaviour in the focusing nonlinear Schrödinger equation, elliptic umbilic catastrophe and the \\\\it tritronquée solution to the Painlevé-I equation %A Boris Dubrovin %A Tamara Grava %A Christian Klein %X We argue that the critical behaviour near the point of ``gradient catastrophe\\\" of the solution to the Cauchy problem for the focusing nonlinear Schr\\\\\\\"odinger equation $ i\\\\epsilon \\\\psi_t +\\\\frac{\\\\epsilon^2}2\\\\psi_{xx}+ |\\\\psi|^2 \\\\psi =0$ with analytic initial data of the form $\\\\psi(x,0;\\\\epsilon) =A(x) e^{\\\\frac{i}{\\\\epsilon} S(x)}$ is approximately described by a particular solution to the Painlev\\\\\\\'e-I equation. %B J. Nonlinear Sci. 19 (2009) 57-94 %G en_US %U http://hdl.handle.net/1963/2525 %1 1593 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-12-11T13:11:26Z\\nNo. of bitstreams: 1\\n0704.0501v3.pdf: 568190 bytes, checksum: cf8471fc01eea53ce252339eda81b3cd (MD5) %R 10.1007/s00332-008-9025-y %0 Journal Article %J Comm. Math. Phys. 286 (2009) 979-1009 %D 2009 %T Universality of the break-up profile for the KdV equation in the small dispersion limit using the Riemann-Hilbert approach %A Tamara Grava %A Tom Claeys %X We obtain an asymptotic expansion for the solution of the Cauchy problem for the Korteweg-de Vries (KdV) equation in the small dispersion limit near the point of gradient catastrophe (x_c,t_c) for the solution of the dispersionless equation.\\nThe sub-leading term in this expansion is described by the smooth solution of a fourth order ODE, which is a higher order analogue to the Painleve I equation. This is in accordance with a conjecture of Dubrovin, suggesting that this is a universal phenomenon for any Hamiltonian perturbation of a hyperbolic equation. Using the Deift/Zhou steepest descent method applied on the Riemann-Hilbert problem for the KdV equation, we are able to prove the asymptotic expansion rigorously in a double scaling limit. %B Comm. Math. Phys. 286 (2009) 979-1009 %G en_US %U http://hdl.handle.net/1963/2636 %1 1487 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-04-22T10:17:48Z\\nNo. of bitstreams: 1\\n0801.2326v1.pdf: 375000 bytes, checksum: b00b6e0d823d47a002430b4fdecf8c7c (MD5) %R 10.1007/s00220-008-0680-5 %0 Journal Article %J Boll. Unione Mat. Ital. (9) 2 (2009) 371-390 %D 2009 %T A variational model for quasistatic crack growth in nonlinear elasticity: some qualitative properties of the solutions %A Gianni Dal Maso %A Alessandro Giacomini %A Marcello Ponsiglione %B Boll. Unione Mat. Ital. (9) 2 (2009) 371-390 %G en_US %U http://hdl.handle.net/1963/2675 %1 1425 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-06-26T15:44:13Z\\nNo. of bitstreams: 1\\nDM-Gia-Pon.pdf: 242504 bytes, checksum: 3b08c25331a3436a5766d41df8e937f7 (MD5) %0 Journal Article %J Trans. Amer. Math. Soc. 361 (2009) 41-59 %D 2009 %T On viscosity solutions of Hamilton-Jacobi equations %A Sandro Zagatti %X We consider the Dirichlet problem for Hamilton-Jacobi equations and prove existence, uniqueness and continuous dependence on boundary data of Lipschitz continuous maximal viscosity solutions. %B Trans. Amer. Math. Soc. 361 (2009) 41-59 %I American Mathematical Society %G en_US %U http://hdl.handle.net/1963/3420 %1 915 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-01-12T11:15:26Z\\nNo. of bitstreams: 1\\nvisco1.pdf: 200249 bytes, checksum: d80a45752b5394539504d0029276b1dc (MD5) %R 10.1090/S0002-9947-08-04557-1 %0 Journal Article %J Frontiers of Mathematics in China %D 2008 %T Cantor families of periodic solutions for completely resonant wave equations %A Massimiliano Berti %A Philippe Bolle %X We present recent existence results of Cantor families of small amplitude periodic solutions for completely resonant nonlinear wave equations. The proofs rely on the Nash-Moser implicit function theory and variational methods. © 2008 Higher Education Press. %B Frontiers of Mathematics in China %V 3 %P 151-165 %G eng %R 10.1007/s11464-008-0011-3 %0 Journal Article %J Advances in Mathematics %D 2008 %T Cantor families of periodic solutions for wave equations via a variational principle %A Massimiliano Berti %A Philippe Bolle %X We prove existence of small amplitude periodic solutions of completely resonant wave equations with frequencies in a Cantor set of asymptotically full measure, via a variational principle. A Lyapunov-Schmidt decomposition reduces the problem to a finite dimensional bifurcation equation-variational in nature-defined on a Cantor set of non-resonant parameters. The Cantor gaps are due to "small divisors" phenomena. To solve the bifurcation equation we develop a suitable variational method. In particular, we do not require the typical "Arnold non-degeneracy condition" of the known theory on the nonlinear terms. As a consequence our existence results hold for new generic sets of nonlinearities. © 2007 Elsevier Inc. All rights reserved. %B Advances in Mathematics %V 217 %P 1671-1727 %G eng %R 10.1016/j.aim.2007.11.004 %0 Journal Article %J Nonlinear Differential Equations and Applications %D 2008 %T Cantor families of periodic solutions of wave equations with C k nonlinearities %A Massimiliano Berti %A Philippe Bolle %X We prove bifurcation of Cantor families of periodic solutions for wave equations with nonlinearities of class C k . It requires a modified Nash-Moser iteration scheme with interpolation estimates for the inverse of the linearized operators and for the composition operators. © 2008 Birkhaueser. %B Nonlinear Differential Equations and Applications %V 15 %P 247-276 %G eng %R 10.1007/s00030-007-7025-5 %0 Journal Article %J Front. Math. China 3 (2008) 239-252 %D 2008 %T Concentrating solutions of some singularly perturbed elliptic equations %A Andrea Malchiodi %X We study singularly perturbed elliptic equations arising from models in physics or biology, and investigate the asymptotic behavior of some special solutions. We also discuss some connections with problems arising in differential geometry. %B Front. Math. China 3 (2008) 239-252 %G en_US %U http://hdl.handle.net/1963/2657 %1 1466 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-05-12T13:25:45Z\\nNo. of bitstreams: 1\\nprocmalchiodi.pdf: 183157 bytes, checksum: 5d6ee64d87eb139b09968558c74ab0f5 (MD5) %R 10.1007/s11464-008-0015-z %0 Journal Article %J Proc. Roy. Soc. Edinburgh Sect. A 138 (2008) 873-896 %D 2008 %T Convergence of equilibria of three-dimensional thin elastic beams %A Maria Giovanna Mora %A Stefan Mueller %X A convergence result is proved for the equilibrium configurations of a three-dimensional thin elastic beam, as the diameter $h$ of the cross-section tends to zero. More precisely, we show that stationary points of the nonlinear elastic functional $E^h$, whose energies (per unit cross-section) are bounded by $Ch^2$, converge to stationary points of the $\\\\varGamma$-limit of $E^h/h^2$. This corresponds to a nonlinear one-dimensional model for inextensible rods, describing bending and torsion effects. The proof is based on the rigidity estimate for low-energy deformations by Friesecke, James and Müller and on a compensated compactness argument in a singular geometry. In addition, possible concentration effects of the strain are controlled by a careful truncation argument. %B Proc. Roy. Soc. Edinburgh Sect. A 138 (2008) 873-896 %G en_US %U http://hdl.handle.net/1963/1896 %1 2339 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-11-24T10:09:06Z\\nNo. of bitstreams: 1\\n69M-2006.pdf: 3633291 bytes, checksum: b5dba64c671bbcd8b87e52ce24963341 (MD5) %R 10.1017/S0308210506001120 %0 Journal Article %J Boll. Unione Mat. Ital. (9) 1 (2008) 497-505 %D 2008 %T Decomposition results for functions with bounded variation %A Gianni Dal Maso %A Rodica Toader %B Boll. Unione Mat. Ital. (9) 1 (2008) 497-505 %I Unione Matematica Italiana %G en_US %U http://hdl.handle.net/1963/3535 %1 729 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-02-23T10:23:36Z\\nNo. of bitstreams: 1\\nDM-Toa.pdf: 186814 bytes, checksum: bbc754f60013f0d8fd61b90a278ac837 (MD5) %0 Journal Article %J Bioinformatics 24 (2008) 1510-1515 %D 2008 %T Discerning static and causal interactions in genome-wide reverse engineering problems %A Mattia Zampieri %A Nicola Soranzo %A Claudio Altafini %X Background. In the past years devicing methods for discovering gene regulatory mechanisms at a genome-wide level has become a fundamental topic in the field of system biology. The aim is to infer gene-gene interactions in a more sophisticated and reliable way through the continuously improvement of reverse engineering algorithms exploiting microarray technologies. Motivation. This work is inspired by the several studies suggesting that co-expression is mostly related to \\\"static\\\" stable binding relationships, like belonging to the same protein complex, rather than other types of interactions more of a \\\"causal\\\" and transient nature (metabolic pathway or transcription factor-binding site interaction). Discerning static relationships from causal ones on the basis of their characteristic regulatory structures and in particular identifing \\\"dense modules\\\" with protein complex, and \\\"sparse modules\\\" with causal interactions such as those between transcription factor and corresponding binding site, the performances of different network inference algorithms in artificial and real networks (derived from E.coli and S.cerevisiae) can be tested and compared. Results. Our study shows that methods that try to prune indirect interactions from the inferred gene networks may fail to retrieve genes co-participating in a protein complex. On the other hand they are more robust in the identification of transcription factor-binding sites dependences when multiple transcription factors regulate the expression of the same gene. In the end we confirm the stronger co-expression regarding genes belonging to a protein complex than transcription factor-binding site, according, also, to the effect of multiple transcription factors and a low expression variance. %B Bioinformatics 24 (2008) 1510-1515 %G en_US %U http://hdl.handle.net/1963/2757 %1 1943 %2 Physics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-08-29T08:29:34Z\\nNo. of bitstreams: 1\\nZaSoAl08.pdf: 5513978 bytes, checksum: a0f45096ba7e82edddd03194f8623b1f (MD5) %R 10.1093/bioinformatics/btn220 %0 Journal Article %J Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 19 (2008) 65-72 %D 2008 %T Entire solutions of autonomous equations on Rn with nontrivial asymptotics %A Andrea Malchiodi %X We prove existence of a new type of solutions for the semilinear equation $- \\\\D u + u = u^p$ on $\\\\R^n$, with $1 < p < \\\\frac{n+2}{n-2}$. These solutions are positive, bounded, decay exponentially to zero away from three half-lines with a common origin, and at infinity are asymptotically periodic. %B Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 19 (2008) 65-72 %G en_US %U http://hdl.handle.net/1963/2640 %1 1483 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-04-30T08:06:29Z\\nNo. of bitstreams: 1\\ngluingnote.pdf: 178833 bytes, checksum: eca0da57985e983d19aac5964c9a1e55 (MD5) %0 Journal Article %J J. Hyperbolic Differ. Equ. 5 (2008) 643-662 %D 2008 %T An entropy based Glimm-type functional %A Laura Caravenna %B J. Hyperbolic Differ. Equ. 5 (2008) 643-662 %I World Scientific %G en_US %U http://hdl.handle.net/1963/4051 %1 351 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-09-09T11:15:30Z\\nNo. of bitstreams: 1\\nglimm.potential.pdf: 405855 bytes, checksum: e2a5f3fed36ffe727c6d43240482aa6d (MD5) %R 10.1142/S0219891608001635 %0 Journal Article %J Nuovo Cimento B 123 (2008) 181-192 %D 2008 %T Equivalent definitions of asymptotic 100% B.E.C. %A Alessandro Michelangeli %X In the mathematical analysis Bose-Einstein condensates, in particular in the study of the quantum dynamics, some kind of factorisation property has been recently proposed as a convenient technical assumption of condensation. After having surveyed both the standard definition of complete Bose-Einstein condensation in the limit of infinitely many particles and some forms of asymptotic factorisation, we prove that these characterisations are equivalent. %B Nuovo Cimento B 123 (2008) 181-192 %G en_US %U http://hdl.handle.net/1963/2546 %1 1573 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-01-10T13:15:49Z\\nNo. of bitstreams: 1\\nsissa_preprint102_07.pdf: 215355 bytes, checksum: a09c310627ed3ed9acf1156596e7dd7e (MD5) %R 10.1393/ncb/i2008-10521-y %0 Journal Article %J SIAM J. Math. Anal. 40 (2008) 1104-1122 %D 2008 %T Eulerian calculus for the displacement convexity in the Wasserstein distance %A Sara Daneri %A Giuseppe Savare\' %X In this paper we give a new proof of the (strong) displacement convexity of a class of integral functionals defined on a compact Riemannian manifold satisfying a lower Ricci curvature bound. Our approach does not rely on existence and regularity results for optimal transport maps on Riemannian manifolds, but it is based on the Eulerian point of view recently introduced by Otto and Westdickenberg [SIAM J. Math. Anal., 37 (2005), pp. 1227-1255] and on the metric characterization of the gradient flows generated by the functionals in the Wasserstein space. %B SIAM J. Math. Anal. 40 (2008) 1104-1122 %I SIAM %G en_US %U http://hdl.handle.net/1963/3413 %1 922 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-01-09T12:32:55Z\\nNo. of bitstreams: 1\\n0801.2455v1.pdf: 504916 bytes, checksum: 7ccfac515ef559e376c7e7d213bd4091 (MD5) %R 10.1137/08071346X %0 Journal Article %J Ann. of Math. 168 (2008) 813-858 %D 2008 %T Existence of conformal metrics with constant $Q$-curvature %A Zindine Djadli %A Andrea Malchiodi %X Given a compact four dimensional manifold, we prove existence of conformal metrics with constant $Q$-curvature under generic assumptions. The problem amounts to solving a fourth-order nonlinear elliptic equation with variational structure. Since the corresponding Euler functional is in general unbounded from above and from below, we employ topological methods and minimax schemes, jointly with a compactness result by the second author. %B Ann. of Math. 168 (2008) 813-858 %G en_US %U http://hdl.handle.net/1963/2308 %1 1708 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-29T14:05:55Z\\nNo. of bitstreams: 1\\nDjadliMalchiodiFinal.pdf: 342979 bytes, checksum: fc2b0b8e4e01a5327ed8e01dc1bae6c5 (MD5) %0 Journal Article %J International Journal for Numerical Methods in Fluids %D 2008 %T Fluid–structure interaction problems in free surface flows: Application to boat dynamics %A L. Formaggia %A E. Miglio %A A. Mola %A N. Parolini %B International Journal for Numerical Methods in Fluids %I Wiley %V 56 %P 965–978 %G eng %U https://doi.org/10.1002/fld.1583 %R 10.1002/fld.1583 %0 Journal Article %J SIAM J. Math. Anal. 40 (2008) 382-412 %D 2008 %T Forced Vibrations of a Nonhomogeneous String %A Pietro Baldi %A Massimiliano Berti %X We prove existence of vibrations of a nonhomogeneous string under a nonlinear time periodic forcing term in the case in which the forcing frequency avoids resonances with the vibration modes of the string (nonresonant case). The proof relies on a Lyapunov-Schmidt reduction and a Nash-Moser iteration scheme. %B SIAM J. Math. Anal. 40 (2008) 382-412 %G en_US %U http://hdl.handle.net/1963/2643 %1 1480 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-05-07T08:29:52Z\\nNo. of bitstreams: 1\\nBaldiBerti06-1.pdf: 277037 bytes, checksum: 6abb75a412da123c87879c25714e41b2 (MD5) %R 10.1137/060665038 %0 Journal Article %J Adv. Math. 219 (2008) 780-837 %D 2008 %T Frobenius Manifolds and Central Invariants for the Drinfeld - Sokolov Bihamiltonian Structures %A Boris Dubrovin %A Liu Si-Qi %A Zhang Youjin %X The Drinfeld - Sokolov construction associates a hierarchy of bihamiltonian integrable systems with every untwisted affine Lie algebra. We compute the complete set of invariants of the related bihamiltonian structures with respect to the group of Miura type transformations. %B Adv. Math. 219 (2008) 780-837 %G en_US %U http://hdl.handle.net/1963/2523 %1 1595 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-12-11T12:52:04Z\\nNo. of bitstreams: 1\\n0710.3115v1.pdf: 569666 bytes, checksum: e3e72944ffd5f097ccaf975d2df90986 (MD5) %R 10.1016/j.aim.2008.06.009 %0 Journal Article %J Phys. Rev. B 77 (2008) 245105 %D 2008 %T Fulde-Ferrell-Larkin-Ovchinnikov pairing in one-dimensional optical lattices %A Matteo Rizzi %A Marco Polini %A Miguel A. Cazalilla %A M.R. Bakhtiari %A Mario P. Tosi %A Rosario Fazio %X Spin-polarized attractive Fermi gases in one-dimensional (1D) optical lattices are expected to be remarkably good candidates for the observation of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase. We model these systems with an attractive Hubbard model with population imbalance. By means of the density-matrix renormalization-group method we compute the pairing correlations as well as the static spin and charge structure factors in the whole range from weak to strong coupling. We demonstrate that pairing correlations exhibit quasi-long range order and oscillations at the wave number expected from FFLO theory. However, we also show by numerically computing the mixed spin-charge static structure factor that charge and spin degrees of freedom appear to be coupled already for small imbalance. We discuss the consequences of this coupling for the observation of the FFLO phase, as well as for the stabilization of the quasi-long range order into long-range order by coupling many identical 1D systems, as in quasi-1D optical lattices. %B Phys. Rev. B 77 (2008) 245105 %G en_US %U http://hdl.handle.net/1963/2694 %1 1406 %2 Physics %3 Condensed Matter Theory %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-07-14T09:46:14Z\\nNo. of bitstreams: 1\\n0712.3364v1.pdf: 305409 bytes, checksum: 13081c375909264afc4c0282b9de9f68 (MD5) %R 10.1103/PhysRevB.77.245105 %0 Journal Article %J Discrete Contin. Dyn. Syst. 20 (2008) 801-822 %D 2008 %T A Gauss-Bonnet-like formula on two-dimensional almost-Riemannian manifolds %A Andrei Agrachev %A Ugo Boscain %A Mario Sigalotti %X We consider a generalization of Riemannian geometry that naturally arises in the framework of control theory. Let $X$ and $Y$ be two smooth vector fields on a two-dimensional manifold $M$. If $X$ and $Y$ are everywhere linearly independent, then they define a classical Riemannian metric on $M$ (the metric for which they are orthonormal) and they give to $M$ the structure of metric space. If $X$ and $Y$ become linearly dependent somewhere on $M$, then the corresponding Riemannian metric has singularities, but under generic conditions the metric structure is still well defined. Metric structures that can be defined locally in this way are called almost-Riemannian structures. They are special cases of rank-varying sub-Riemannian structures, which are naturally defined in terms of submodules of the space of smooth vector fields on $M$. Almost-Riemannian structures show interesting phenomena, in particular for what concerns the relation between curvature, presence of conjugate points, and topology of the manifold. The main result of the paper is a generalization to almost-Riemannian structures of the Gauss-Bonnet formula. %B Discrete Contin. Dyn. Syst. 20 (2008) 801-822 %G en_US %U http://hdl.handle.net/1963/1869 %1 2353 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-10-11T07:14:06Z\\nNo. of bitstreams: 1\\nmath.oc0609566.pdf: 920147 bytes, checksum: c6f020bc9676ee3966b64f4135e4ce52 (MD5) %R 10.3934/dcds.2008.20.801 %0 Journal Article %J Netw. Heterog. Media 3 (2008) 567-614 %D 2008 %T Globally stable quasistatic evolution in plasticity with softening %A Gianni Dal Maso %A Antonio DeSimone %A Maria Giovanna Mora %A Massimiliano Morini %X We study a relaxed formulation of the quasistatic evolution problem in the context of small strain associative elastoplasticity with softening. The relaxation takes place in spaces of generalized Young measures. The notion of solution is characterized by the following properties: global stability at each time and energy balance on each\\ntime interval. An example developed in detail compares the solutions obtained by this method with the ones provided by a vanishing viscosity approximation, and shows that only the latter capture a decreasing branch in the stress-strain response. %B Netw. Heterog. Media 3 (2008) 567-614 %G en_US %U http://hdl.handle.net/1963/1965 %1 2228 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-05-15T11:03:21Z\\nNo. of bitstreams: 1\\nDM-DeS-Mor-Mor-05-3-final.pdf: 395475 bytes, checksum: 5789494df44986207d416d5d1ea15d22 (MD5) %0 Journal Article %J Calc. Var. Partial Differential Equations 31 (2008) 137-145 %D 2008 %T Gradient bounds for minimizers of free discontinuity problems related to cohesive zone models in fracture mechanics %A Gianni Dal Maso %A Adriana Garroni %X In this note we consider a free discontinuity problem for a scalar function, whose energy depends also on the size of the jump. We prove that the gradient of every smooth local minimizer never exceeds a constant, determined only by the data of the problem. %B Calc. Var. Partial Differential Equations 31 (2008) 137-145 %G en_US %U http://hdl.handle.net/1963/1723 %1 2428 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-01-26T12:52:13Z\\nNo. of bitstreams: 1\\nmath.AP0507088.pdf: 132125 bytes, checksum: 444c743b7852d0f6e97bb318f49b4467 (MD5) %R 10.1007/s00526-006-0084-3 %0 Journal Article %J Russian Mathematical Surveys. Volume 63, Issue 6, 2008, Pages 999-1010 %D 2008 %T Hamiltonian partial differential equations and Frobenius manifolds %A Boris Dubrovin %X In the first part of this paper the theory of Frobenius manifolds\\r\\nis applied to the problem of classification of Hamiltonian systems of partial\\r\\ndifferential equations depending on a small parameter. Also developed is\\r\\na deformation theory of integrable hierarchies including the subclass of\\r\\nintegrable hierarchies of topological type. Many well-known examples\\r\\nof integrable hierarchies, such as the Korteweg–de Vries, non-linear\\r\\nSchr¨odinger, Toda, Boussinesq equations, and so on, belong to this\\r\\nsubclass that also contains new integrable hierarchies. Some of these new\\r\\nintegrable hierarchies may be important for applications. Properties of the\\r\\nsolutions to these equations are studied in the second part. Consideration\\r\\nis given to the comparative study of the local properties of perturbed and\\r\\nunperturbed solutions near a point of gradient catastrophe. A Universality\\r\\nConjecture is formulated describing the various types of critical behaviour\\r\\nof solutions to perturbed Hamiltonian systems near the point of gradient\\r\\ncatastrophe of the unperturbed solution. %B Russian Mathematical Surveys. Volume 63, Issue 6, 2008, Pages 999-1010 %I SISSA %G en %U http://hdl.handle.net/1963/6471 %1 6416 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Boris Dubrovin (dubrovin@sissa.it) on 2013-02-11T14:46:43Z\\nNo. of bitstreams: 1\\ndubrovin_2008_umn.pdf: 417000 bytes, checksum: 093ef887f6154d0c26771476cae72503 (MD5) %R 10.1070/RM2008v063n06ABEH004575 %0 Report %D 2008 %T Instanton counting on Hirzebruch surfaces %A Ugo Bruzzo %A Rubik Poghossian %A Alessandro Tanzini %X We perform a study of the moduli space of framed torsion free sheaves on Hirzebruch surfaces by using localization techniques. After discussing general properties of this moduli space, we classify its fixed points under the appropriate toric action and compute its Poincare\\\' polynomial. From the physical viewpoint, our results provide the partition function of N=4 Vafa-Witten theory on Hirzebruch surfaces, which is relevant in black hole entropy counting problems according to a conjecture due to Ooguri, Strominger and Vafa. %G en_US %U http://hdl.handle.net/1963/2852 %1 1848 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-05T18:06:43Z\\nNo. of bitstreams: 1\\n0809.0155v1.pdf: 212427 bytes, checksum: f5060bd4e1da6a5215a488041ef018ff (MD5) %0 Journal Article %J SIAM J. Control Optim. 47 (2008) 1851-1878 %D 2008 %T Invariant Carnot-Caratheodory metrics on S3, SO(3), SL(2) and Lens Spaces %A Ugo Boscain %A Francesco Rossi %X In this paper we study the invariant Carnot-Caratheodory metrics on SU(2) \\\' S3,\\nSO(3) and SL(2) induced by their Cartan decomposition. Beside computing explicitly geodesics and conjugate loci, we compute the cut loci (globally) and we give the expression of the Carnot-Caratheodory distance as the inverse of an elementary function. We then prove that the metric\\ngiven on SU(2) projects on the so called Lens Spaces L(p; q). Also for Lens Spaces, we compute\\nthe cut loci (globally). %B SIAM J. Control Optim. 47 (2008) 1851-1878 %G en_US %U http://hdl.handle.net/1963/2144 %1 2099 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-27T08:46:25Z\\nNo. of bitstreams: 1\\nBoscain-Rossi-2007.pdf: 587872 bytes, checksum: 6b4998700cd692ddbd99e14289405bdf (MD5) %R 10.1137/070703727 %0 Report %D 2008 %T Invariant Manifolds for Viscous Profiles of a Class of Mixed Hyperbolic-Parabolic Systems %A Stefano Bianchini %A Laura Spinolo %G en_US %U http://hdl.handle.net/1963/3400 %1 932 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-12-15T12:03:08Z\\nNo. of bitstreams: 1\\nBianchini_Spinolo.pdf: 146920 bytes, checksum: 27283c16ae26e782e9f0d17c1fbb29d4 (MD5) %0 Journal Article %J Comm. Math. Phys. 279 (2008) 77-116 %D 2008 %T The Isospectral Dirac Operator on the 4-dimensional Orthogonal Quantum Sphere %A Francesco D\'Andrea %A Ludwik Dabrowski %A Giovanni Landi %X Equivariance under the action of Uq(so(5)) is used to compute the left regular and (chiral) spinorial representations of the algebra of the quantum Euclidean 4-sphere S^4_q. These representations are the constituents of a spectral triple on this sphere with a Dirac operator which is isospectral to the canonical one of the spin structure of the round undeformed four-sphere and which gives metric dimension four for the noncommutative geometry. Non-triviality of the geometry is proved by pairing the associated Fredholm module with an `instanton\\\' projection. A real structure which satisfies all required properties modulo a suitable ideal of `infinitesimals\\\' is also introduced. %B Comm. Math. Phys. 279 (2008) 77-116 %G en_US %U http://hdl.handle.net/1963/2567 %1 1553 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-01-18T11:00:40Z\\nNo. of bitstreams: 1\\n0611100v1.pdf: 351975 bytes, checksum: 8dd0f817683bd7782e5110ca6b585b91 (MD5) %R 10.1007/s00220-008-0420-x %0 Journal Article %J SIAM J. Control Optim. 47 (2008) 111-143 %D 2008 %T Limit Time Optimal Syntheses for a control-affine system on S² %A Paolo Mason %A Rebecca Salmoni %A Ugo Boscain %A Yacine Chitour %X For $\\\\alpha \\\\in ]0,\\\\pi/2[$, let $(\\\\Sigma)_\\\\alpha$ be the control system $\\\\dot{x}=(F+uG)x$, where $x$ belongs to the two-dimensional unit sphere $S^2$, $u\\\\in [-1,1]$, and $F,G$ are $3\\\\times3$ skew-symmetric matrices generating rotations with perpendicular axes and of respective norms $\\\\cos(\\\\alpha)$ and $\\\\sin(\\\\alpha)$. In this paper, we study the time optimal synthesis (TOS) from the north pole $(0,0,1)^T$ associated to $(\\\\Sigma)_\\\\alpha$, as the parameter $\\\\alpha$ tends to zero; this problem is motivated by specific issues in the control of quantum systems. We first prove that the TOS is characterized by a \\\"two-snakes\\\" configuration on the whole $S^2$, except for a neighborhood $U_\\\\alpha$ of the south pole $(0,0,-1)^T$ of diameter at most ${\\\\cal O}(\\\\alpha)$. We next show that, inside $U_\\\\alpha$, the TOS depends on the relationship between $r(\\\\alpha):=\\\\pi/2\\\\alpha-[\\\\pi/2\\\\alpha]$ and $\\\\alpha$. More precisely, we characterize three main relationships by considering sequences $(\\\\alpha_k)_{k\\\\geq 0}$ satisfying (a) $r(\\\\alpha_k)=\\\\bar{r}$, (b) $r(\\\\alpha_k)=C\\\\alpha_k$, and (c) $r(\\\\alpha_k)=0$, where $\\\\bar{r}\\\\in (0,1)$ and $C>0$. In each case, we describe the TOS and provide, after a suitable rescaling, the limiting behavior, as $\\\\alpha$ tends to zero, of the corresponding TOS inside $U_\\\\alpha$. %B SIAM J. Control Optim. 47 (2008) 111-143 %G en_US %U http://hdl.handle.net/1963/1862 %1 2360 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-09-28T11:24:18Z\\nNo. of bitstreams: 1\\n48-M.pdf: 5823285 bytes, checksum: 7f66cf9d280da78b56a423c415d9078c (MD5) %R 10.1137/060675988 %0 Journal Article %J J.Phys.A: Math.Theor. 41,(2008), 205201-205247 %D 2008 %T On the Logarithmic Asymptotics of the Sixth Painleve\' Equation (Summer 2007) %A Davide Guzzetti %X We study the solutions of the sixth Painlev\'e equation with a logarithmic\r\nasymptotic behavior at a critical point. We compute the monodromy group\r\nassociated to the solutions by the method of monodromy preserving deformations\r\nand we characterize the asymptotic behavior in terms of the monodromy itself. %B J.Phys.A: Math.Theor. 41,(2008), 205201-205247 %I SISSA %G en %U http://hdl.handle.net/1963/6521 %1 6473 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Davide Guzzetti (guzzetti@sissa.it) on 2013-03-12T10:36:09Z\nNo. of bitstreams: 1\n0801.1157v4.pdf: 449572 bytes, checksum: 6c4042b70a0d361af61282bee96d84db (MD5) %R 10.1088/1751-8113/41/20/205201 %0 Journal Article %J Discrete Contin. Dyn. Syst. 21 (2008) 625-641 %D 2008 %T Minimization of non quasiconvex functionals by integro-extremization method %A Sandro Zagatti %B Discrete Contin. Dyn. Syst. 21 (2008) 625-641 %G en_US %U http://hdl.handle.net/1963/2761 %1 1939 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-08-29T10:49:03Z\\nNo. of bitstreams: 1\\ndcdsprep.pdf: 193173 bytes, checksum: dc350ec75ad4fad83ec12ee96aaddabe (MD5) %R 10.3934/dcds.2008.21.625 %0 Journal Article %J Calc. Var. Partial Differential Equations 31 (2008) 511-519 %D 2008 %T Minimizers of non convex scalar functionals and viscosity solutions of Hamilton-Jacobi equations %A Sandro Zagatti %B Calc. Var. Partial Differential Equations 31 (2008) 511-519 %G en_US %U http://hdl.handle.net/1963/2760 %1 1940 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-08-29T10:38:03Z\\nNo. of bitstreams: 1\\nxugrad1.pdf: 129424 bytes, checksum: e067ce39ac2059a9ee78b46fc06884c3 (MD5) %R 10.1007/s00526-007-0124-7 %0 Journal Article %J Adv. Differential Equations 13 (2008) 1109-1129 %D 2008 %T Morse theory and a scalar field equation on compact surfaces %A Andrea Malchiodi %B Adv. Differential Equations 13 (2008) 1109-1129 %I Khayyam Publishing %G en_US %U http://hdl.handle.net/1963/3531 %1 733 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-02-20T09:55:31Z\\nNo. of bitstreams: 1\\nMalchiodi07.pdf: 259636 bytes, checksum: f8380ae02625bce2ba51c6bf7dcb737d (MD5) %0 Journal Article %J Commun. Contemp. Math. 10 (2008) 391-404 %D 2008 %T Multiple bound states for the Schroedinger-Poisson problem %A Antonio Ambrosetti %A David Ruiz %B Commun. Contemp. Math. 10 (2008) 391-404 %G en_US %U http://hdl.handle.net/1963/2679 %1 1421 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-07-01T12:26:30Z\\nNo. of bitstreams: 1\\nAmbrosettiRuiz06.pdf: 226363 bytes, checksum: 59048d8662e1823466ba8f56a48d2808 (MD5) %R 10.1142/S021919970800282X %0 Journal Article %J Int. Math. Res. Not. vol. 2008, Article ID rnn038 %D 2008 %T Noncommutative families of instantons %A Giovanni Landi %A Chiara Pagani %A Cesare Reina %A Walter D. van Suijlekom %X We construct $\\\\theta$-deformations of the classical groups SL(2,H) and Sp(2). Coacting on the basic instanton on a noncommutative four-sphere $S^4_\\\\theta$, we construct a noncommutative family of instantons of charge 1. The family is parametrized by the quantum quotient of $SL_\\\\theta(2,H)$ by $Sp_\\\\theta(2)$. %B Int. Math. Res. Not. vol. 2008, Article ID rnn038 %I Oxford University Press %G en_US %U http://hdl.handle.net/1963/3417 %1 918 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-01-12T09:40:47Z\\nNo. of bitstreams: 1\\n0710.0721v2.pdf: 290960 bytes, checksum: 7203f1e1dd34fd90d8d3201c7b813b44 (MD5) %R 10.1093/imrn/rnn038 %0 Journal Article %J Rev. Math. Phys. 20 (2008) 979-1006 %D 2008 %T The Noncommutative Geometry of the Quantum Projective Plane %A Francesco D\'Andrea %A Ludwik Dabrowski %A Giovanni Landi %X We study the spectral geometry of the quantum projective plane CP^2_q. In particular, we construct a Dirac operator which gives a 0^+ summable triple, equivariant under U_q(su(3)). %B Rev. Math. Phys. 20 (2008) 979-1006 %G en_US %U http://hdl.handle.net/1963/2548 %1 1571 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-01-14T08:17:29Z\\nNo. of bitstreams: 1\\n0712.3401v1.pdf: 305773 bytes, checksum: 85ef21e8ac9485f12064685740331fc2 (MD5) %R 10.1142/S0129055X08003493 %0 Report %D 2008 %T A note on the differentiability of Lipschitz functions and the chain rule in Sobolev spaces %A Massimiliano Morini %G en_US %U http://hdl.handle.net/1963/2654 %1 1469 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-05-12T11:42:20Z\\nNo. of bitstreams: 1\\nchainmor.pdf: 232603 bytes, checksum: 2798c276d92d0d30c48523748c30a163 (MD5) %0 Journal Article %J Proc. R. Soc. A 464 (2008) 733-757 %D 2008 %T Numerical study of a multiscale expansion of the Korteweg-de Vries equation and Painlevé-II equation %A Tamara Grava %A Christian Klein %X The Cauchy problem for the Korteweg de Vries (KdV) equation with small dispersion of order $\\\\e^2$, $\\\\e\\\\ll 1$, is characterized by the appearance of a zone of rapid modulated oscillations. These oscillations are approximately described by the elliptic solution of KdV where the amplitude, wave-number and frequency are not constant but evolve according to the Whitham equations. Whereas the difference between the KdV and the asymptotic solution decreases as $\\\\epsilon$ in the interior of the Whitham oscillatory zone, it is known to be only of order $\\\\epsilon^{1/3}$ near the leading edge of this zone. To obtain a more accurate description near the leading edge of the oscillatory zone we present a multiscale expansion of the solution of KdV in terms of the Hastings-McLeod solution of the Painlev\\\\\\\'e-II equation. We show numerically that the resulting multiscale solution approximates the KdV solution, in the small dispersion limit, to the order $\\\\epsilon^{2/3}$. %B Proc. R. Soc. A 464 (2008) 733-757 %G en_US %U http://hdl.handle.net/1963/2592 %1 1530 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-02-25T15:08:44Z\\nNo. of bitstreams: 1\\n0708.0638v3.pdf: 453744 bytes, checksum: 05291095860df236125f0d9f8c676fbb (MD5) %R 10.1098/rspa.2007.0249 %0 Journal Article %J J. Nonlinear Sci. 18 (2008) 277-302 %D 2008 %T Optimal Strokes for Low Reynolds Number Swimmers: An Example %A Francois Alouges %A Antonio DeSimone %A Aline Lefebvre %X Swimming, i.e., being able to advance in the absence of external forces by performing cyclic shape changes, is particularly demanding at low Reynolds numbers. This is the regime of interest for micro-organisms and micro- or nano-robots. We focus in this paper on a simple yet representative example: the three-sphere swimmer of Najafi and Golestanian (Phys. Rev. E, 69, 062901-062904, 2004). For this system, we show how to cast the problem of swimming in the language of control theory, prove global controllability (which implies that the three-sphere swimmer can indeed swim), and propose a numerical algorithm to compute optimal strokes (which turn out to be suitably defined sub-Riemannian geodesics). %B J. Nonlinear Sci. 18 (2008) 277-302 %I Springer %G en_US %U http://hdl.handle.net/1963/4006 %1 396 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-08-26T10:49:24Z\\nNo. of bitstreams: 1\\nADL2008a.pdf: 273047 bytes, checksum: 36ba2c2914fff62c05124f1ac1453733 (MD5) %R 10.1007/s00332-007-9013-7 %0 Journal Article %J PLoS ONE 3 (2008) e2981 %D 2008 %T Origin of Co-Expression Patterns in E.coli and S.cerevisiae Emerging from Reverse Engineering Algorithms %A Mattia Zampieri %A Nicola Soranzo %A Daniele Bianchini %A Claudio Altafini %X Background: The concept of reverse engineering a gene network, i.e., of inferring a genome-wide graph of putative genegene interactions from compendia of high throughput microarray data has been extensively used in the last few years to deduce/integrate/validate various types of \\\"physical\\\" networks of interactions among genes or gene products. Results: This paper gives a comprehensive overview of which of these networks emerge significantly when reverse engineering large collections of gene expression data for two model organisms, E.coli and S.cerevisiae, without any prior information. For the first organism the pattern of co-expression is shown to reflect in fine detail both the operonal structure of the DNA and the regulatory effects exerted by the gene products when co-participating in a protein complex. For the second organism we find that direct transcriptional control (e.g., transcription factor-binding site interactions) has little statistical significance in comparison to the other regulatory mechanisms (such as co-sharing a protein complex, colocalization on a metabolic pathway or compartment), which are however resolved at a lower level of detail than in E.coli. Conclusion: The gene co-expression patterns deduced from compendia of profiling experiments tend to unveil functional categories that are mainly associated to stable bindings rather than transient interactions. The inference power of this systematic analysis is substantially reduced when passing from E.coli to S.cerevisiae. This extensive analysis provides a way to describe the different complexity between the two organisms and discusses the critical limitations affecting this type of methodologies. %B PLoS ONE 3 (2008) e2981 %G en_US %U http://hdl.handle.net/1963/2722 %1 1379 %2 Physics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-08-25T15:50:20Z\\nNo. of bitstreams: 1\\nPLOSe2981.pdf: 853455 bytes, checksum: 91361e24e96e09bbaa6f3083a73e3db4 (MD5) %R 10.1371/journal.pone.0002981 %0 Journal Article %J Communications on Pure and Applied Analysis %D 2008 %T On periodic elliptic equations with gradient dependence %A Massimiliano Berti %A Matzeu, M %A Valdinoci, E %X We construct entire solutions of Δu = f(x, u, ∇u) which are superpositions of odd, periodic functions and linear ones, with prescribed integer or rational slope. %B Communications on Pure and Applied Analysis %V 7 %P 601-615 %G eng %0 Journal Article %J Math. Models Methods Appl. Sci. 18 (2008) 1-20 %D 2008 %T Relaxation of some transversally isotropic energies and applications to smectic A elastomers %A James Adams %A Sergio Conti %A Antonio DeSimone %A Georg Dolzmann %B Math. Models Methods Appl. Sci. 18 (2008) 1-20 %G en_US %U http://hdl.handle.net/1963/1912 %1 2325 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-02-02T14:15:25Z\\nNo. of bitstreams: 1\\nsma_Preprint_SISSA.pdf: 271875 bytes, checksum: eb0cf2c367021718506356a73bda219a (MD5) %R 10.1142/S0218202508002693 %0 Journal Article %J Calc. Var. Partial Differential Equations 33 (2008) 37-74 %D 2008 %T A second order minimality condition for the Mumford-Shah functional %A Filippo Cagnetti %A Maria Giovanna Mora %A Massimiliano Morini %X A new necessary minimality condition for the Mumford-Shah functional is derived by means of second order variations. It is expressed in terms of a sign condition for a nonlocal quadratic form on $H^1_0(\\\\Gamma)$, $\\\\Gamma$ being a submanifold of the regular part of the discontinuity set of the critical point. Two equivalent formulations are provided: one in terms of the first eigenvalue of a suitable compact operator, the other involving a sort of nonlocal capacity of $\\\\Gamma$. A sufficient condition for minimality is also deduced. Finally, an explicit example is discussed, where a complete characterization of the domains where the second variation is nonnegative can be given. %B Calc. Var. Partial Differential Equations 33 (2008) 37-74 %G en_US %U http://hdl.handle.net/1963/1955 %1 2318 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-03-02T12:54:00Z\\nNo. of bitstreams: 1\\nCMM.pdf: 358759 bytes, checksum: c414c0080a17971ecba1251a5890b94f (MD5) %R 10.1007/s00526-007-0152-3 %0 Journal Article %J Int. Math. Res. Not. vol. 2008, article ID rnn035 %D 2008 %T On semistable principal bundles over a complex projective manifold %A Indranil Biswas %A Ugo Bruzzo %X Let G be a simple linear algebraic group defined over the complex numbers. Fix a proper parabolic subgroup P of G and a nontrivial antidominant character \\\\chi of P. We prove that a holomorphic principal G-bundle E over a connected complex projective manifold M is semistable and the second Chern class of its adjoint bundle vanishes in rational cohomology if and only if the line bundle over E/P defined by \\\\chi is numerically effective. Similar results remain valid for principal bundles with a reductive linear algebraic group as the structure group. These generalize an earlier work of Y. Miyaoka where he gave a characterization of semistable vector bundles over a smooth projective curve. Using these characterizations one can also produce similar criteria for the semistability of parabolic principal bundles over a compact Riemann surface. %B Int. Math. Res. Not. vol. 2008, article ID rnn035 %I Oxford University Press %G en_US %U http://hdl.handle.net/1963/3418 %1 917 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-01-12T09:53:34Z\\nNo. of bitstreams: 1\\n0803.4042v1.pdf: 273878 bytes, checksum: 8f729aa65d9cebf234016c17cacfedbc (MD5) %R 10.1093/imrn/rnn035 %0 Journal Article %J J. Funct. Anal. 254 (2008) 2816-2845 %D 2008 %T Solitons of linearly coupled systems of semilinear non-autonomous equations on Rn %A Antonio Ambrosetti %A Giovanna Cerami %A David Ruiz %X Using concentration compactness type arguments, we prove some results about the existence of positive ground and bound state of linearly coupled systems of nonlinear Schrödinger equations. %B J. Funct. Anal. 254 (2008) 2816-2845 %G en_US %U http://hdl.handle.net/1963/2175 %1 2069 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-04T08:29:15Z\\nNo. of bitstreams: 1\\nambceruiz.pdf: 305881 bytes, checksum: f00a4a8078e5c5d78d4309cceb317906 (MD5) %R 10.1016/j.jfa.2007.11.013 %0 Journal Article %J Commun. Pure Appl. Anal. 7 (2008) 1-21 %D 2008 %T Stability of planar switched systems: the nondiagonalizable case %A Ugo Boscain %A Moussa Balde %B Commun. Pure Appl. Anal. 7 (2008) 1-21 %G en_US %U http://hdl.handle.net/1963/1857 %1 2361 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-09-28T09:15:19Z\\nNo. of bitstreams: 1\\n44-M.pdf: 3158552 bytes, checksum: c4fee14d81a9fcf026efd4448da88c75 (MD5) %R 10.3934/cpaa.2008.7.1 %0 Journal Article %J Algebra Number Theory 2 (2008) 313-345 %D 2008 %T Symmetric obstruction theories and Hilbert schemes of points on threefolds %A Kai Behrend %A Barbara Fantechi %X In an earlier paper by one of us (Behrend), Donaldson-Thomas type invariants were expressed as certain weighted Euler characteristics of the moduli space. The Euler characteristic is weighted by a certain canonical\\nZ-valued constructible function on the moduli space. This constructible function associates to\\nany point of the moduli space a certain invariant of the singularity of the space at the point. Here we evaluate this invariant for the case of a singularity that is an isolated point of a C∗-action and that admits a symmetric obstruction theory compatible with the C∗-action. The answer is (-1)d, where d\\nis the dimension of the Zariski tangent space. We use this result to prove that for any threefold, proper or not, the weighted Euler characteristic of the Hilbert scheme of n points on the threefold is, up to sign, equal to the usual Euler characteristic. For the case of a projective Calabi-Yau threefold, we deduce that the Donaldson-Thomas invariant of the Hilbert scheme of n points is, up to sign, equal to the Euler characteristic. This proves a conjecture of Maulik, Nekrasov, Okounkov and Pandharipande. %B Algebra Number Theory 2 (2008) 313-345 %G en_US %U http://hdl.handle.net/1963/2709 %1 1392 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-08-22T08:20:28Z\\nNo. of bitstreams: 1\\n0512556v1.pdf: 377619 bytes, checksum: ba4796d5d4103e23a359d4fe4d01ca2f (MD5) %0 Thesis %D 2008 %T Symmetries of noncommutative spaces and equivariant cohomology %A Lucio Cirio %K Noncommutative spaces %X As the title suggests, the main subject of this thesis is the study of symmetries of noncommutative spaces and related equivariant cohomologies. We focus on deformations of classical geometries coming from the action of some symmetry. A close relation between the deformation of the symmetry and the deformation of the space on which it acts is at the heart of our approach; we will use this idea to generate noncommutative geometries, and to de¯ne algebraic models for the equivariant cohomology of such actions. %I SISSA %G en %U http://hdl.handle.net/1963/5254 %1 5077 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-01-23T08:57:48Z\\nNo. of bitstreams: 1\\nPhD_Cirio.pdf: 579480 bytes, checksum: 59e7b02846b913cd48e3c84e1e9a2bea (MD5) %0 Journal Article %J Adv. Theor. Math. Phys. 12 (2008) 1429-1446 %D 2008 %T Topological Gauge Theories on Local Spaces and Black Hole Entropy Countings %A Giulio Bonelli %A Alessandro Tanzini %X We study cohomological gauge theories on total spaces of holomorphic line bundles over complex manifolds and obtain their reduction to the base manifold by U(1) equivariant localization of the path integral. We exemplify this general mechanism by proving via exact path integral localization a reduction for local curves conjectured in hep-th/0411280, relevant to the calculation of black hole entropy/Gromov-Witten invariants. Agreement with the four-dimensional gauge theory is recovered by taking into account in the latter non-trivial contributions coming from one-loop fluctuations determinants at the boundary of the total space. We also study a class of abelian gauge theories on Calabi-Yau local surfaces, describing the quantum foam for the A-model, relevant to the calculation of Donaldson-Thomas invariants. %B Adv. Theor. Math. Phys. 12 (2008) 1429-1446 %G en_US %U http://hdl.handle.net/1963/1992 %1 2204 %2 Physics %3 Elementary Particle Theory %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-08-09T12:45:15Z\\nNo. of bitstreams: 1\\nhep-th0706.2633v1.pdf: 170115 bytes, checksum: 16cdd3d36705e91d5d429948e55b15a5 (MD5) %0 Journal Article %J Discrete Contin. Dyn. Syst. 21 (2008) 277-294 %D 2008 %T Topological methods for an elliptic equation with exponential nonlinearities %A Andrea Malchiodi %X We consider a class of variational equations with exponential nonlinearities on compact surfaces. From considerations involving the Moser-Trudinger inequality, we characterize some sublevels of the Euler-Lagrange functional in terms of the topology of the surface and of the data of the equation. This is used together with a min-max argument to obtain existence results. %B Discrete Contin. Dyn. Syst. 21 (2008) 277-294 %G en_US %U http://hdl.handle.net/1963/2594 %1 1528 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-02-26T11:51:21Z\\nNo. of bitstreams: 1\\nnotemalchiodi.pdf: 260737 bytes, checksum: eddd4d053e3aa35b1cd0562f82bd0e7e (MD5) %R 10.3934/dcds.2008.21.277 %0 Journal Article %J Ann. Inst. H. Poincare Anal. Non Lineaire 25 (2008) 609-631 %D 2008 %T Transition layer for the heterogeneous Allen-Cahn equation %A Fethi Mahmoudi %A Andrea Malchiodi %A Juncheng Wei %X We consider the equation $\\\\e^{2}\\\\Delta u=(u-a(x))(u^2-1)$ in $\\\\Omega$, $\\\\frac{\\\\partial u}{\\\\partial \\\\nu} =0$ on $\\\\partial \\\\Omega$, where $\\\\Omega$ is a smooth and bounded domain in $\\\\R^n$, $\\\\nu$ the outer unit normal to $\\\\pa\\\\Omega$, and $a$ a smooth function satisfying $-10} and {a<0}. Assuming $\\\\nabla a \\\\neq 0$ on $K$ and $a\\\\ne 0$ on $\\\\partial \\\\Omega$, we show that there exists a sequence $\\\\e_j \\\\to 0$ such that the above equation has a solution $u_{\\\\e_j}$ which converges uniformly to $\\\\pm 1$ on the compact sets of $\\\\O_{\\\\pm}$ as $j \\\\to + \\\\infty$. %B Ann. Inst. H. Poincare Anal. Non Lineaire 25 (2008) 609-631 %G en_US %U http://hdl.handle.net/1963/2656 %1 1467 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-05-12T13:00:33Z\\nNo. of bitstreams: 1\\n0702878v1.pdf: 345060 bytes, checksum: a1e9182e6448c835b1c66b4f226b0b8d (MD5) %R 10.1016/j.anihpc.2007.03.008 %0 Book Section %B Nonlinear PDE’s and Applications : C.I.M.E. Summer School, Cetraro, Italy 2008 / Stefano Bianchini, Eric A. Carlen, Alexander Mielke, Cédric Villani. Eds. Luigi Ambrosio, Giuseppe Savaré. - Berlin : Springer, 2011. - (Lecture Notes in Mathematics ; 20 %D 2008 %T Transport Rays and Applications to Hamilton–Jacobi Equations %A Stefano Bianchini %A Matteo Gloyer %X The aim of these notes is to introduce the readers to the use of the Disintegration Theorem for measures as an effective tool for reducing problems in transport equations to simpler ones. The basic idea is to partition Rd into one dimensional sets, on which the problem under consideration becomes one space dimensional (and thus much easier, hopefully). %B Nonlinear PDE’s and Applications : C.I.M.E. Summer School, Cetraro, Italy 2008 / Stefano Bianchini, Eric A. Carlen, Alexander Mielke, Cédric Villani. Eds. Luigi Ambrosio, Giuseppe Savaré. - Berlin : Springer, 2011. - (Lecture Notes in Mathematics ; 20 %I Springer %@ 978-3-642-21718-0 %G en %U http://hdl.handle.net/1963/5463 %1 5298 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2012-02-14T08:18:09Z\\nNo. of bitstreams: 1\\n20090907.pdf: 179195 bytes, checksum: bcdd57e58d4e0e0c4843018797e609bd (MD5) %R 10.1007/978-3-642-21861-3_1 %0 Journal Article %J Arch. Ration. Mech. Anal. 189 (2008) 469-544 %D 2008 %T A vanishing viscosity approach to quasistatic evolution in plasticity with softening %A Gianni Dal Maso %A Antonio DeSimone %A Maria Giovanna Mora %A Massimiliano Morini %X We deal with quasistatic evolution problems in plasticity with softening, in the framework of small strain associative elastoplasticity. The presence of a nonconvex term due to the softening phenomenon requires a nontrivial extension of the variational framework for rate-independent problems to the case of a nonconvex energy functional. We argue that, in this case, the use of global minimizers in the corresponding incremental problems is not justified from the mechanical point of view. Thus, we analize a different selection criterion for the solutions of the quasistatic evolution problem, based on a viscous approximation. This leads to a generalized formulation in terms of Young measures, developed in the first part of the paper. In the second part we apply our approach to some concrete examples. %B Arch. Ration. Mech. Anal. 189 (2008) 469-544 %G en_US %U http://hdl.handle.net/1963/1844 %1 2373 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-07-21T11:03:58Z\\nNo. of bitstreams: 1\\nmath.AP-0606718.pdf: 563956 bytes, checksum: 80e8ac8a9120c15b452698af3abc77d1 (MD5) %R 10.1007/s00205-008-0117-5 %0 Journal Article %J NATO Science for Peace and Security Series B: Physics and Biophysics %D 2008 %T Variational methods for Hamiltonian PDEs %A Massimiliano Berti %X We present recent existence results of periodic solutions for completely resonant nonlinear wave equations in which both "small divisor" difficulties and infinite dimensional bifurcation phenomena occur. These results can be seen as generalizations of the classical finite-dimensional resonant center theorems of Weinstein-Moser and Fadell-Rabinowitz. The proofs are based on variational bifurcation theory: after a Lyapunov-Schmidt reduction, the small divisor problem in the range equation is overcome with a Nash-Moser implicit function theorem for a Cantor set of non-resonant parameters. Next, the infinite dimensional bifurcation equation, variational in nature, possesses minimax mountain-pass critical points. The big difficulty is to ensure that they are not in the "Cantor gaps". This is proved under weak non-degeneracy conditions. Finally, we also discuss the existence of forced vibrations with rational frequency. This problem requires variational methods of a completely different nature, such as constrained minimization and a priori estimates derivable from variational inequalities. © 2008 Springer Science + Business Media B.V. %B NATO Science for Peace and Security Series B: Physics and Biophysics %P 391-420 %@ 9781402069628 %G eng %R 10.1007/978-1-4020-6964-2-16 %0 Journal Article %J Comm. Pure Appl. Math. 60 (2007) 1559-1622 %D 2007 %T Asymptotic behaviour of smooth solutions for partially dissipative hyperbolic systems with a convex entropy %A Stefano Bianchini %A Bernard Hanouzet %A Roberto Natalini %X We study the asymptotic time behavior of global smooth solutions to general entropy dissipative hyperbolic systems of balance law in m space dimensions, under the Shizuta-Kawashima condition. %B Comm. Pure Appl. Math. 60 (2007) 1559-1622 %G en_US %U http://hdl.handle.net/1963/1780 %1 2764 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-30T10:33:17Z\\nNo. of bitstreams: 1\\n83M.pdf: 393359 bytes, checksum: f3f7b61564332b98b8706af95942dd69 (MD5) %R 10.1002/cpa.20195 %0 Journal Article %J Ann. Henri Poincar´e 8 (2007), 301–336 %D 2007 %T The Asymptotic Behaviour of the Fourier Transforms of Orthogonal Polynomials II: L.I.F.S. Measures and Quantum Mechanics %A Davide Guzzetti %A Giorgio Mantica %X We study measures generated by systems of linear iterated functions,\r\ntheir Fourier transforms, and those of their orthogonal polynomials. We\r\ncharacterize the asymptotic behaviours of their discrete and continuous averages.\r\nFurther related quantities are analyzed, and relevance of this analysis\r\nto quantum mechanics is briefly discussed %B Ann. Henri Poincar´e 8 (2007), 301–336 %I 2007 Birkh¨auser Verlag Basel/Switzerland %G en %1 6480 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Davide Guzzetti (guzzetti@sissa.it) on 2013-03-13T10:11:23Z\nNo. of bitstreams: 1\n11-GuzMantica07.pdf: 924495 bytes, checksum: 5897cbac3fb5b378b02bf5cdae1273ea (MD5) %R 10.1007/s00023-006-0309-1 %0 Journal Article %J Arch. Ration. Mech. Anal. 183 (2007) 163-185 %D 2007 %T Asymptotic variational wave equations %A Alberto Bressan %A Zhang Ping %A Zheng Yuxi %X We investigate the equation $(u_t + (f(u))_x)_x = f\\\'\\\'(u) (u_x)^2/2$ where $f(u)$ is a given smooth function. Typically $f(u)= u^2/2$ or $u^3/3$. This equation models unidirectional and weakly nonlinear waves for the variational wave equation $u_{tt} - c(u) (c(u)u_x)_x =0$ which models some liquid crystals with a natural sinusoidal $c$. The equation itself is also the Euler-Lagrange equation of a variational problem. Two natural classes of solutions can be associated with this equation. A conservative solution will preserve its energy in time, while a dissipative weak solution loses energy at the time when singularities appear. Conservative solutions are globally defined, forward and backward in time, and preserve interesting geometric features, such as the Hamiltonian structure. On the other hand, dissipative solutions appear to be more natural from the physical point of view.\\nWe establish the well-posedness of the Cauchy problem within the class of conservative solutions, for initial data having finite energy and assuming that the flux function $f$ has Lipschitz continuous second-order derivative. In the case where $f$ is convex, the Cauchy problem is well-posed also within the class of dissipative solutions. However, when $f$ is not convex, we show that the dissipative solutions do not depend continuously on the initial data. %B Arch. Ration. Mech. Anal. 183 (2007) 163-185 %G en_US %U http://hdl.handle.net/1963/2182 %1 2062 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-05T07:08:27Z\\nNo. of bitstreams: 1\\n0502124v1.pdf: 205978 bytes, checksum: a1efb4667d7315509947b4d7a4999bd1 (MD5) %R 10.1007/s00205-006-0014-8 %0 Report %D 2007 %T Black Holes, Instanton Counting on Toric Singularities and q-Deformed Two-Dimensional Yang-Mills Theory %A Luca Griguolo %A Domenico Seminara %A Richard J. Szabo %A Alessandro Tanzini %X We study the relationship between instanton counting in N=4 Yang-Mills theory on a generic four-dimensional toric orbifold and the semi-classical expansion of q-deformed Yang-Mills theory on the blowups of the minimal resolution of the orbifold singularity, with an eye to clarifying the recent proposal of using two-dimensional gauge theories to count microstates of black holes in four dimensions. We describe explicitly the instanton contributions to the counting of D-brane bound states which are captured by the two-dimensional gauge theory. We derive an intimate relationship between the two-dimensional Yang-Mills theory and Chern-Simons theory on generic Lens spaces, and use it to show that the correct instanton counting is only reproduced when the Chern-Simons contributions are treated as non-dynamical boundary conditions in the D4-brane gauge theory. We also use this correspondence to discuss the counting of instantons on higher genus ruled Riemann surfaces. %B Nucl. Phys. B 772 (2007) 1-24 %G en_US %U http://hdl.handle.net/1963/1888 %1 2347 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-11-09T10:57:35Z\\nNo. of bitstreams: 1\\nhep-th0610155.pdf: 340757 bytes, checksum: fb3e5bfec5e2a4c15d97a9ca6f2e8a0a (MD5) %R 10.1016/j.nuclphysb.2007.02.030 %0 Thesis %D 2007 %T Bose-Einstein condensation: Analysis of problems and rigorous results %A Alessandro Michelangeli %K Bose-Einstein condensation %X This work is an up-to-date and partially improved analysis of the basics of the mathematical description of Bose-Einstein condensation in terms of first principles of Quantum Mechanics... %I SISSA %G en %U http://hdl.handle.net/1963/5272 %1 5096 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-01-24T10:19:10Z\\nNo. of bitstreams: 1\\nPhD_Michelangeli.pdf: 1695749 bytes, checksum: 95d156c08cc32b740e854bc7d79fbc5f (MD5) %0 Report %D 2007 %T Bose-Einstein condensation: analysis of problems and rigorous results %A Alessandro Michelangeli %G en_US %U http://hdl.handle.net/1963/2189 %1 2055 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-08T06:59:18Z\\nNo. of bitstreams: 1\\n70-2007MP.pdf: 1694233 bytes, checksum: 36e2ed8af8e03d149a0b11cccfd01634 (MD5) %0 Journal Article %J J. Fixed Point Theory Appl. 1 (2007) 305-336 %D 2007 %T Boundary interface for the Allen-Cahn equation %A Andrea Malchiodi %A Juncheng Wei %B J. Fixed Point Theory Appl. 1 (2007) 305-336 %G en_US %U http://hdl.handle.net/1963/2027 %1 2169 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-03T11:10:26Z\\nNo. of bitstreams: 1\\nMalchiodiWei07.pdf: 379788 bytes, checksum: 4c87f76e7db9858a9acfeca0a8ec75c1 (MD5) %R 10.1007/s11784-007-0016-7 %0 Journal Article %J Pacific Journal of Mathematics 229 (2007), No. 2, 447–468 %D 2007 %T Boundary-clustered interfaces for the Allen–Cahn equation %A Andrea Malchiodi %A Wei-Ming Ni %A Juncheng Wei %B Pacific Journal of Mathematics 229 (2007), No. 2, 447–468 %I Mathematical Sciences Publishers %G en %U http://hdl.handle.net/1963/5089 %1 4905 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-11-17T13:19:29Z\\nNo. of bitstreams: 1\\nmnw-pjm-final.pdf: 287316 bytes, checksum: 2a18e3af66be7b9b793a528138cf493a (MD5) %0 Report %D 2007 %T BV instability for the Lax-Friedrichs scheme %A Paolo Baiti %A Alberto Bressan %A Helge Kristian Jenssen %X It is proved that discrete shock profiles (DSPs) for the Lax-Friedrichs scheme for a system of conservation laws do not necessarily depend continuously in BV on their speed. We construct examples of $2 \\\\times 2$-systems for which there are sequences of DSPs with speeds converging to a rational number. Due to a resonance phenomenon, the difference between the limiting DSP and any DSP in the sequence will contain an order-one amount of variation. %G en_US %U http://hdl.handle.net/1963/2335 %1 1681 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-11-05T09:55:21Z\\nNo. of bitstreams: 1\\n0502043v1.pdf: 257155 bytes, checksum: 5055aa260394ac1339fa775b656f3b15 (MD5) %0 Journal Article %J Comm. Math. Phys. 271 (2007) 289-373 %D 2007 %T Canonical structure and symmetries of the Schlesinger equations %A Boris Dubrovin %A Marta Mazzocco %X The Schlesinger equations S (n,m) describe monodromy preserving deformations of order m Fuchsian systems with n+1 poles. They can be considered as a family of commuting time-dependent Hamiltonian systems on the direct product of n copies of m×m matrix algebras equipped with the standard linear Poisson bracket. In this paper we present a new canonical Hamiltonian formulation ofthe general Schlesinger equations S (n,m) for all n, m and we compute the action of the symmetries of the Schlesinger equations in these coordinates. %B Comm. Math. Phys. 271 (2007) 289-373 %G en_US %U http://hdl.handle.net/1963/1997 %1 2199 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-08-30T08:59:18Z\\nNo. of bitstreams: 1\\nmathDG0311261v4.pdf: 748258 bytes, checksum: c550bb118062fa82741da16a2735b68f (MD5) %R 10.1007/s00220-006-0165-3 %0 Journal Article %J International Journal of Mathematics. Volume 18, Issue 9, October 2007, Pages 1009-1059 %D 2007 %T Chen-Ruan cohomology of ADE singularities %A Fabio Perroni %K Chen-Ruan cohomology, Ruan\'s conjecture, McKay correspondence %X We study Ruan\'s \\textit{cohomological crepant resolution conjecture} for\r\norbifolds with transversal ADE singularities. In the $A_n$-case we compute both\r\nthe Chen-Ruan cohomology ring $H^*_{\\rm CR}([Y])$ and the quantum corrected\r\ncohomology ring $H^*(Z)(q_1,...,q_n)$. The former is achieved in general, the\r\nlater up to some additional, technical assumptions. We construct an explicit\r\nisomorphism between $H^*_{\\rm CR}([Y])$ and $H^*(Z)(-1)$ in the $A_1$-case,\r\nverifying Ruan\'s conjecture. In the $A_n$-case, the family\r\n$H^*(Z)(q_1,...,q_n)$ is not defined for $q_1=...=q_n=-1$. This implies that\r\nthe conjecture should be slightly modified. We propose a new conjecture in the\r\n$A_n$-case which we prove in the $A_2$-case by constructing an explicit\r\nisomorphism. %B International Journal of Mathematics. Volume 18, Issue 9, October 2007, Pages 1009-1059 %I SISSA %G en %U http://hdl.handle.net/1963/6502 %1 6447 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Fabio Perroni (perroni@sissa.it) on 2013-02-27T13:02:56Z\nNo. of bitstreams: 1\nmath_0605207v2.pdf: 502025 bytes, checksum: c85d5727542636dfdf53276f3ceaf9cd (MD5) %R 10.1142/S0129167X07004436 %0 Journal Article %D 2007 %T The cohomological crepant resolution conjecture for P(1,3,4,4) %A Samuel Boissiere %A Fabio Perroni %A Etienne Mann %X We prove the cohomological crepant resolution conjecture of Ruan for the\r\nweighted projective space P(1,3,4,4). To compute the quantum corrected\r\ncohomology ring we combine the results of Coates-Corti-Iritani-Tseng on\r\nP(1,1,1,3) and our previous results. %I SISSA %G en %U http://hdl.handle.net/1963/6513 %1 6464 %2 Mathematics %4 1 %# MAT/03 GEOMETRIA %$ Submitted by Fabio Perroni (perroni@sissa.it) on 2013-02-28T17:55:28Z\nNo. of bitstreams: 1\n0712.3248v1.pdf: 182952 bytes, checksum: a5a581e6ba586472b9418608365283cf (MD5) %0 Journal Article %J Bioinformatics 23 (2007) 1640-1647 %D 2007 %T Comparing association network algorithms for reverse engineering of large scale gene regulatory networks: synthetic vs real data %A Nicola Soranzo %A Ginestra Bianconi %A Claudio Altafini %X Motivation: Inferring a gene regulatory network exclusively from microarray expression profiles is a difficult but important task. The aim of this work is to compare the predictive power of some of the most popular algorithms in different conditions (like data taken at equilibrium or time courses) and on both synthetic and real microarray data. We are in particular interested in comparing similarity measures both of linear type (like correlations and partial correlations) and of nonlinear type (mutual information and conditional mutual information), and in investigating the underdetermined case (less samples than genes). Results: In our simulations we see that all network inference algorithms obtain better performances from data produced with \\\"structural\\\" perturbations, like gene knockouts at steady state, than with any dynamical perturbation. The predictive power of all algorithms is confirmed on a reverse engineering problem from E. coli gene profiling data: the edges of the \\\"physical\\\" network of transcription factor-binding sites are significantly overrepresented among the highest weighting edges of the graph that we infer directly from the data without any structure supervision. Comparing synthetic and in vivo data on the same network graph allows us to give an indication of how much more complex a real transcriptional regulation program is with respect to an artificial model. Availability: Software and supplementary material are freely available at the URL http://people.sissa.it/~altafini/papers/SoBiAl07/ %B Bioinformatics 23 (2007) 1640-1647 %G en_US %U http://hdl.handle.net/1963/2028 %1 2168 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-03T12:44:53Z\\nNo. of bitstreams: 1\\nSoBiAl07.pdf: 261510 bytes, checksum: dde8f62bdbd57a761204f8533569885a (MD5) %R 10.1093/bioinformatics/btm163 %0 Report %D 2007 %T The complete one-loop spin chain for N=2 Super-Yang-Mills %A Paolo Di Vecchia %A Alessandro Tanzini %X We show that the complete planar one-loop mixing matrix of the N=2 Super Yang--Mills theory can be obtained from a reduction of that of the N=4 theory. For composite operators of scalar fields, this yields an anisotropic XXZ spin chain, whose spectrum of excitations displays a mass gap. %G en_US %U http://hdl.handle.net/1963/2309 %1 1707 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-29T14:28:13Z\\nNo. of bitstreams: 1\\n0412283v1.pdf: 110673 bytes, checksum: 9f881078e3eb69765e2c6e294569fd70 (MD5) %0 Report %D 2007 %T Computing Amplitudes in topological M-theory %A Giulio Bonelli %A Alessandro Tanzini %A Maxim Zabzine %X We define a topological quantum membrane theory on a seven dimensional manifold of $G_2$ holonomy. We describe in detail the path integral evaluation for membrane geometries given by circle bundles over Riemann surfaces. We show that when the target space is $CY_3\\\\times S^1$ quantum amplitudes of non-local observables of membranes wrapping the circle reduce to the A-model amplitudes. \\nIn particular for genus zero we show that our model computes the Gopakumar-Vafa invariants. Moreover, for membranes wrapping calibrated homology spheres in the $CY_3$, we find that the amplitudes of our model are related to Joyce invariants. %B JHEP 03 (2007) 023 %G en_US %U http://hdl.handle.net/1963/1901 %1 2335 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-12-07T16:26:28Z\\nNo. of bitstreams: 1\\nhep-th0611327.pdf: 307312 bytes, checksum: 9a3a9891aca40624a44c7a531765695b (MD5) %R 10.1088/1126-6708/2007/03/023 %0 Journal Article %J Adv. Math. 209 (2007) 460-525 %D 2007 %T Concentration on minimal submanifolds for a singularly perturbed Neumann problem %A Fethi Mahmoudi %A Andrea Malchiodi %X We consider the equation $- \\\\e^2 \\\\D u + u= u^p$ in $\\\\Omega \\\\subseteq \\\\R^N$, where $\\\\Omega$ is open, smooth and bounded, and we prove concentration of solutions along $k$-dimensional minimal submanifolds of $\\\\partial \\\\O$, for $N \\\\geq 3$ and for $k \\\\in \\\\{1, ..., N-2\\\\}$. We impose Neumann boundary conditions, assuming $13 or with two inputs for n=4 and n=5, up to state-feedback transformations, preserving the affine structure. First using the Poincare series of moduli numbers we introduce the intrinsic numbers of functional moduli of each prescribed number of variables on which a classification problem depends. In order to classify affine systems with scalar input we associate with such a system the canonical frame by normalizing some structural functions in a commutative relation of the vector fields, which define our control system. Then, using this canonical frame, we introduce the canonical coordinates and find a complete system of state-feedback invariants of the system. It also gives automatically the micro-local (i.e. local in state-input space) classification of the generic non-affine n-dimensional control system with scalar input for n>2. Further we show how the problem of feedback-equivalence of affine systems with two-dimensional input in state space of dimensions 4 and 5 can be reduced to the same problem for affine systems with scalar input. In order to make this reduction we distinguish the subsystem of our control system, consisting of the directions of all extremals in dimension 4 and all abnormal extremals in dimension 5 of the time optimal problem, defined by the original control system. In each classification problem under consideration we find the intrinsic numbers of functional moduli of each prescribed number of variables according to its Poincare series. %B SIAM J. Control Optim. 46 (2007) 1431-1460 %G en_US %U http://hdl.handle.net/1963/2186 %1 2058 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-05T09:10:03Z\\nNo. of bitstreams: 1\\n0502031v2.pdf: 352804 bytes, checksum: 261d7075283ef8321d485a773ab50353 (MD5) %R 10.1137/050623711 %0 Report %D 2007 %T Feedback control of spin systems %A Claudio Altafini %X The feedback stabilization problem for ensembles of coupled spin 1/2 systems is discussed from a control theoretic perspective. The noninvasive nature of the bulk measurement allows for a fully unitary and deterministic closed loop. The Lyapunov-based feedback design presented does not require spins that are selectively addressable. With this method, it is possible to obtain control inputs also for difficult tasks, like suppressing undesired couplings in identical spin systems. %B Quantum Inf. Process. 6 (2007) 9-36 %G en_US %U http://hdl.handle.net/1963/1808 %1 2406 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-04-12T07:08:54Z\\nNo. of bitstreams: 1\\nquant-ph0601016.pdf: 557249 bytes, checksum: 7285125f31ec5e7e75c04033506d986b (MD5) %R 10.1007/s11128-006-0038-x %0 Journal Article %J 45th IEEE Conference on Decision and Control (2007) 2471-2476 %D 2007 %T Feedback stabilization of quantum ensembles: a global convergence analysis on complex flag manifolds %A Claudio Altafini %X In an N-level quantum mechanical system, the problem of unitary feedback stabilization of mixed density operators to periodic orbits admits a natural Lyapunov-based time-varying feedback design. A global description of the domain of attraction of the closed-loop system can be provided based on a \\\"root-space\\\"-like structure of the space of density operators. This convex set foliates as a complex flag manifold where each leaf is identified with the coadjoint orbit of the eigenvalues of the density operator. The converging conditions are time-independent but depend from the topology of the flag manifold: it is shown that the closed loop must have a number of equilibria at least equal to the Euler characteristic of the manifold, thus imposing obstructions of topological nature to global stabilizability. %B 45th IEEE Conference on Decision and Control (2007) 2471-2476 %G en_US %U http://hdl.handle.net/1963/1729 %1 2422 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-01-30T13:15:57Z\\nNo. of bitstreams: 1\\nquant-ph0506268.pdf: 339036 bytes, checksum: 0deeffc30853814638abac71df2a136d (MD5) %R 10.1109/CDC.2006.377774 %0 Journal Article %J Ann. Inst. Henri Poincare-Prob. Stat. 43 (2007) 399-415 %D 2007 %T On finite-dimensional projections of distributions for solutions of randomly forced PDE\\\'s %A Andrei Agrachev %A Sergei Kuksin %A Andrey Sarychev %A Armen Shirikyan %X The paper is devoted to studying the image of probability measures on a Hilbert space under finite-dimensional analytic maps. We establish sufficient conditions under which the image of a measure has a density with respect to the Lebesgue measure and continuously depends on the map. The results obtained are applied to the 2D Navier-Stokes equations perturbed by various random forces of low dimension. %B Ann. Inst. Henri Poincare-Prob. Stat. 43 (2007) 399-415 %G en_US %U http://hdl.handle.net/1963/2012 %1 2184 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-08-31T09:21:55Z\\nNo. of bitstreams: 1\\nmathAP0603295v1.pdf: 316127 bytes, checksum: 6686ad78dcb2dbc5efb64a959b30750c (MD5) %R 10.1016/j.anihpb.2006.06.001 %0 Journal Article %J Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 18 (2007) 333-342 %D 2007 %T Gaussian estimates for hypoelliptic operators via optimal control %A Ugo Boscain %A Sergio Polidoro %X We obtain Gaussian lower bounds for the fundamental solution of a class of hypoelliptic equations, by using repeatedly an invariant Harnack inequality. Our main result is given in terms of the value function of a suitable optimal control problem. %B Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 18 (2007) 333-342 %G en_US %U http://hdl.handle.net/1963/1994 %1 2202 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-08-09T13:14:42Z\\nNo. of bitstreams: 1\\n45-2007M.pdf: 181670 bytes, checksum: 6f262dccd2b3004cfd0b0b711bd011b2 (MD5) %R 10.4171/RLM/499 %0 Report %D 2007 %T High-order angles in almost-Riemannian geometry %A Ugo Boscain %A Mario Sigalotti %X Let X and Y be two smooth vector fields on a two-dimensional manifold M. If X and Y are everywhere linearly independent, then they define a Riemannian metric on M (the metric for which they are orthonormal) and they give to M the structure of metric space. If X and Y become linearly dependent somewhere on M, then the corresponding Riemannian metric has singularities, but under generic conditions the metric structure is still well defined. Metric structures that can be defined locally in this way are called almost-Riemannian structures. The main result of the paper is a generalization to almost-Riemannian structures of the Gauss-Bonnet formula for domains with piecewise-C2 boundary. The main feature of such formula is the presence of terms that play the role of high-order angles at the intersection points with the set of singularities. %G en_US %U http://hdl.handle.net/1963/1995 %1 2201 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-08-24T12:00:46Z\\nNo. of bitstreams: 1\\nhigh-order.pdf: 168685 bytes, checksum: 11d6f55bf9b07b4da01dae3f3deb969a (MD5) %0 Journal Article %J JHEP 10 (2007) 060 %D 2007 %T The holomorphic anomaly for open string moduli %A Giulio Bonelli %A Alessandro Tanzini %X We complete the holomorphic anomaly equations for topological strings with their dependence on open moduli. We obtain the complete system by standard path integral arguments generalizing the analysis of BCOV (Commun. Math. Phys. 165 (1994) 311) to strings with boundaries. We study both the anti-holomorphic dependence on open moduli and on closed moduli in presence of Wilson lines. By providing the compactification a\\\' la Deligne-Mumford of the moduli space of Riemann surfaces with boundaries, we show that the open holomorphic anomaly equations are structured on the (real codimension one) boundary components of this space. %B JHEP 10 (2007) 060 %G en_US %U http://hdl.handle.net/1963/2113 %1 2576 %2 Physics %3 Elementary Particle Theory %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-17T09:24:42Z\\nNo. of bitstreams: 1\\n0708.2627v2.pdf: 199897 bytes, checksum: 38929fe4fa52ddd01dd4af02292f3058 (MD5) %R 10.1088/1126-6708/2007/10/060 %0 Journal Article %J Phys. Rev. Lett. 98 (2007) 030404 %D 2007 %T Luther-Emery Phase and Atomic-Density Waves in a Trapped Fermion Gas %A Gao Xianlong %A Matteo Rizzi %A Marco Polini %A Rosario Fazio %A Mario P. Tosi %A Vivaldo L. Jr. Campo %A Klaus Capelle %X The Luther-Emery liquid is a state of matter that is predicted to occur in one-dimensional systems of interacting fermions and is characterized by a gapless charge spectrum and a gapped spin spectrum. In this Letter we discuss a realization of the Luther-Emery phase in a trapped cold-atom gas. We study by means of the density-matrix renormalization-group technique a two-component atomic Fermi gas with attractive interactions subject to parabolic trapping inside an optical lattice. We demonstrate how this system exhibits compound phases characterized by the coexistence of spin pairing and atomic-density waves. A smooth crossover occurs with increasing magnitude of the atom-atom attraction to a state in which tightly bound spin-singlet dimers occupy the center of the trap. The existence of atomic-density waves could be detected in the elastic contribution to the light-scattering diffraction pattern. %B Phys. Rev. Lett. 98 (2007) 030404 %G en_US %U http://hdl.handle.net/1963/2056 %1 2140 %2 Physics %3 Condensed Matter Theory %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-06T11:46:28Z\\nNo. of bitstreams: 1\\ncond-mat0609346v1.pdf: 218755 bytes, checksum: 06a409d540e05ece03bbac85198ee19c (MD5) %R 10.1103/PhysRevLett.98.030404 %0 Report %D 2007 %T On the Maz\\\'ya inequalities: existence and multiplicity results for an elliptic problem involving cylindrical weights %A Marita Gazzini %A Roberta Musina %G en_US %U http://hdl.handle.net/1963/2522 %1 1596 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-12-11T12:04:02Z\\nNo. of bitstreams: 1\\nGazzini.pdf: 266073 bytes, checksum: eb239636fd06715d381d38055d96481e (MD5) %0 Journal Article %J J. Reine Angew. Math. 612 (2007) 59-79 %D 2007 %T Metrics on semistable and numerically effective Higgs bundles %A Ugo Bruzzo %A Beatriz Grana-Otero %X We consider fibre metrics on Higgs vector bundles on compact K\\\\\\\"ahler manifolds, providing notions of numerical effectiveness and numerical flatness in terms of such metrics. We prove several properties of bundles satisfying such conditions and in particular we show that numerically flat Higgs bundles have vanishing Chern classes, and that they admit filtrations whose quotients are stable flat Higgs bundles. We compare these definitions with those previously given in the case of projective varieties. Finally we study the relations between numerically effectiveness and semistability, providing semistability criteria for Higgs bundles on projective manifolds of any dimension. %B J. Reine Angew. Math. 612 (2007) 59-79 %G en_US %U http://hdl.handle.net/1963/1840 %1 2376 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-06-19T08:20:16Z\\nNo. of bitstreams: 1\\nmath.DG-0605659.pdf: 242976 bytes, checksum: b5e79cfd73f6c6533a0ae12bad3e3c90 (MD5) %R 10.1515/CRELLE.2007.084 %0 Report %D 2007 %T Multi-bump solitons to linearly coupled systems of nonlinear Schrödinger equations %A Antonio Ambrosetti %A Eduardo Colorado %A David Ruiz %B Calc. Var. Partial Differential Equations 30 (2007) 85-112 %G en_US %U http://hdl.handle.net/1963/1835 %1 2381 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-06-13T09:30:35Z\\nNo. of bitstreams: 1\\n29M-2006.pdf: 394371 bytes, checksum: de96976aa35a5289ec5ab93a664b9be5 (MD5) %R 10.1007/s00526-006-0079-0 %0 Journal Article %J Ann. Inst. H. Poincare Anal. Non Lineaire 24 (2007) 279-310 %D 2007 %T Nearly time optimal stabilizing patchy feedbacks %A Fabio Ancona %A Alberto Bressan %X We consider the time optimal stabilization problem for a nonlinear control system $\\\\dot x=f(x,u)$. Let $\\\\tau(y)$ be the minimum time needed to steer the system from the state $y\\\\in\\\\R^n$ to the origin, and call $\\\\A(T)$ the set of initial states that can be steered to the origin in time $\\\\tau(y)\\\\leq T$. Given any $\\\\ve>0$, in this paper we construct a patchy feedback $u=U(x)$ such that every solution of $\\\\dot x=f(x, U(x))$, $x(0)=y\\\\in \\\\A(T)$ reaches an $\\\\ve$-neighborhood of the origin within time $\\\\tau(y)+\\\\ve$. %B Ann. Inst. H. Poincare Anal. Non Lineaire 24 (2007) 279-310 %G en_US %U http://hdl.handle.net/1963/2185 %1 2059 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-05T08:22:02Z\\nNo. of bitstreams: 1\\n0512531v1.pdf: 428805 bytes, checksum: 8eae0ca68a7339938991d987a677d6f9 (MD5) %R 10.1016/j.anihpc.2006.03.010 %0 Journal Article %J J. Eur. Math. Soc. (JEMS) 9 (2007) 219-252 %D 2007 %T Necessary and sufficient conditions for the chain rule in $W\\\\sp 1,1\\\\sb \\\\rm loc(\\\\Bbb R\\\\sp N;\\\\Bbb R\\\\sp d)$ and $\\\\rm BV\\\\sb \\\\rm loc(\\\\Bbb R\\\\sp N;\\\\Bbb R\\\\sp d)$ %A Giovanni Leoni %A Massimiliano Morini %X In this paper we prove necessary and sufficient conditions for the validity of the classical chain rule in Sobolev spaces and in the space of functions of bounded variation. %B J. Eur. Math. Soc. (JEMS) 9 (2007) 219-252 %G en_US %U http://hdl.handle.net/1963/2037 %1 2159 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-03T16:39:37Z\\nNo. of bitstreams: 1\\n05-CNA-001.pdf: 331793 bytes, checksum: b6fd9f7cf79aacffa4d60dda74d183a6 (MD5) %R 10.4171/JEMS/78 %0 Report %D 2007 %T A new model for contact angle hysteresis %A Antonio DeSimone %A Natalie Gruenewald %A Felix Otto %X We present a model which explains several experimental observations relating contact angle hysteresis with surface roughness. The model is based on the balance between released energy and dissipation, and it describes the stick-slip behavior of drops on a rough surface using ideas similar to those employed in dry friction, elasto-plasticity and fracture mechanics. The main results of our analysis are formulas giving the interval of stable contact angles as a function of the surface roughness. These formulas show that the difference between advancing and receding angles is much larger for a drop in complete contact with the substrate (Wenzel drop) than for one whose cavities are filled with air (Cassie-Baxter drop). This fact is used as the key tool to interpret the experimental evidence. %B Netw. Heterog. Media 2 (2007) 211-225 %G en_US %U http://hdl.handle.net/1963/1848 %1 2369 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-07-26T09:50:36Z\\nNo. of bitstreams: 1\\n37-2006M.pdf: 313357 bytes, checksum: ac507409dc660fba3ec468e50c4fe9b1 (MD5) %0 Thesis %D 2007 %T Noncommutative geometry and quantum group symmetries %A Francesco D\'Andrea %K Noncommutative geometry %X It is a widespread belief that mathematics originates from the desire to understand (and eventually to formalize) some aspects of the real world. Quoting [Man07], «we are doing mathematics in order to understand, create, and handle things, and perhaps this understanding is mathematics» . Let me thus begin with a brief discussion of the physical ideas that motivated the development of Noncommutative Geometry and Quantum Group Theory - the areas of mathematics to which this dissertation belongs. Some physicists believe, and Einstein himself expressed this view in [Ein98a], that physics progresses in stages: there is no `final\\\' theory of Nature, but simply a sequence of theories which provide more and more accurate descriptions of the real world... %I SISSA %G en %U http://hdl.handle.net/1963/5269 %1 5093 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-01-24T08:56:37Z\\nNo. of bitstreams: 1\\nPhD_D\\\'Andrea_Francesco.pdf: 1636959 bytes, checksum: 0d673f9b1d591a36bd4883bedc49422a (MD5) %0 Journal Article %J NoDEA 13 (2007) 713-734 %D 2007 %T On a notion of unilateral slope for the Mumford-Shah functional %A Gianni Dal Maso %A Rodica Toader %X In this paper we introduce a notion of unilateral slope for the Mumford-Shah functional, and provide an explicit formula in the case of smooth cracks. We show that the slope is not lower semicontinuous and study the corresponding relaxed functional. %B NoDEA 13 (2007) 713-734 %G en_US %U http://hdl.handle.net/1963/2059 %1 2137 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-06T14:02:51Z\\nNo. of bitstreams: 1\\n0410525v1.pdf: 214576 bytes, checksum: 3722f413401cdb51f778a8c15eeebe71 (MD5) %R 10.1007/s00030-006-4054-4 %0 Journal Article %J J. Phys. A 40 (2007) 14819-14842 %D 2007 %T The number of eigenvalues of three-particle Schrödinger operators on lattices %A Sergio Albeverio %A Gianfausto Dell'Antonio %A Saidakhmat N. Lakaev %X We consider the Hamiltonian of a system of three quantum mechanical particles (two identical fermions and boson)on the three-dimensional lattice $\\\\Z^3$ and interacting by means of zero-range attractive potentials. We describe the location and structure of the essential spectrum of the three-particle discrete Schr\\\\\\\"{o}dinger operator $H_{\\\\gamma}(K),$ $K$ being the total quasi-momentum and $\\\\gamma>0$ the ratio of the mass of fermion and boson.\\nWe choose for $\\\\gamma>0$ the interaction $v(\\\\gamma)$ in such a way the system consisting of one fermion and one boson has a zero energy resonance.\\nWe prove for any $\\\\gamma> 0$ the existence infinitely many eigenvalues of the operator $H_{\\\\gamma}(0).$ We establish for the number $N(0,\\\\gamma; z;)$ of eigenvalues lying below $z<0$ the following asymptotics $$ \\\\lim_{z\\\\to 0-}\\\\frac{N(0,\\\\gamma;z)}{\\\\mid \\\\log \\\\mid z\\\\mid \\\\mid}={U} (\\\\gamma) .$$ Moreover, for all nonzero values of the quasi-momentum $K \\\\in T^3 $ we establish the finiteness of the number $ N(K,\\\\gamma;\\\\tau_{ess}(K))$ of eigenvalues of $H(K)$ below the bottom of the essential spectrum and we give an asymptotics for the number $N(K,\\\\gamma;0)$ of eigenvalues below zero. %B J. Phys. A 40 (2007) 14819-14842 %G en_US %U http://hdl.handle.net/1963/2576 %1 1545 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-01-28T14:20:38Z\\nNo. of bitstreams: 1\\n0703191v1.pdf: 254244 bytes, checksum: a662f118f430d7b424e751fa5f07ed92 (MD5) %R 10.1088/1751-8113/40/49/015 %0 Report %D 2007 %T Numerical solution of the small dispersion limit of Korteweg de Vries and Whitham equations %A Tamara Grava %A Christian Klein %X The Cauchy problem for the Korteweg de Vries (KdV) equation with small dispersion of order $\\\\epsilon^2$, is characterized by the appearance of a zone of rapid modulated oscillations of wave-length of order $\\\\epsilon$. These oscillations are approximately described by the elliptic solution of KdV where the amplitude, wave-number and frequency are not constant but evolve according to the Whitham equations. In this manuscript we give a quantitative analysis of the discrepancy between the numerical solution of the KdV equation in the small dispersion limit and the corresponding approximate solution for values of $\\\\epsilon$ between $10^{-1}$ and $10^{-3}$. The numerical results are compatible with a difference of order $\\\\epsilon$ within the `interior\\\' of the Whitham oscillatory zone, of order $\\\\epsilon^{1/3}$ at the left boundary outside the Whitham zone and of order $\\\\epsilon^{1/2}$ at the right boundary outside the Whitham zone. %B Comm. Pure Appl. Math. 60 (2007) 1623-1664 %G en_US %U http://hdl.handle.net/1963/1788 %1 2756 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-30T13:45:26Z\\nNo. of bitstreams: 1\\n91FM-2005.pdf: 905542 bytes, checksum: 8505fe7c8ac2e5f1da7248d62ae542b2 (MD5) %R 10.1002/cpa.20183 %0 Report %D 2007 %T Numerical study of a multiscale expansion of KdV and Camassa-Holm equation %A Tamara Grava %A Christian Klein %X We study numerically solutions to the Korteweg-de Vries and Camassa-Holm equation close to the breakup of the corresponding solution to the dispersionless equation. The solutions are compared with the properly rescaled numerical solution to a fourth order ordinary differential equation, the second member of the Painlev\\\\\\\'e I hierarchy. It is shown that this solution gives a valid asymptotic description of the solutions close to breakup. We present a detailed analysis of the situation and compare the Korteweg-de Vries solution quantitatively with asymptotic solutions obtained via the solution of the Hopf and the Whitham equations. We give a qualitative analysis for the Camassa-Holm equation %G en_US %U http://hdl.handle.net/1963/2527 %1 1591 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-12-12T12:39:23Z\\nNo. of bitstreams: 1\\n0702038v1.pdf: 367188 bytes, checksum: f88c96f6ff42a7c5378de0118866d4bb (MD5) %0 Report %D 2007 %T Numerically flat Higgs vector bundles %A Ugo Bruzzo %A Beatriz Grana-Otero %X After providing a suitable definition of numerical effectiveness for Higgs bundles, and a related notion of numerical flatness, in this paper we prove, together with some side results, that all Chern classes of a Higgs-numerically flat Higgs bundle vanish, and that a Higgs bundle is Higgs-numerically flat if and only if it is has a filtration whose quotients are flat stable Higgs bundles. We also study the relation between these numerical properties of Higgs bundles and (semi)stability. %B Commun. Contemp. Math. 9 (2007) 437-446 %G en_US %U http://hdl.handle.net/1963/1757 %1 2787 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-21T15:59:56Z\\nNo. of bitstreams: 1\\n39_2005_fm.pdf: 192887 bytes, checksum: 1d32aff78ef27b80046dfc391135d55a (MD5) %R 10.1142/S0219199707002526 %0 Journal Article %J C. R. Math. 345 (2007) 647-652 %D 2007 %T Parametrized curves in Lagrange Grassmannians %A Igor Zelenko %A Li Chengbo %B C. R. Math. 345 (2007) 647-652 %G en_US %U http://hdl.handle.net/1963/2560 %1 1559 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-01-17T13:49:21Z\\nNo. of bitstreams: 1\\n0708.1100v1.pdf: 336234 bytes, checksum: d04e21a2139ddd8622a28c31cd370eed (MD5) %R 10.1016/j.crma.2007.10.034 %0 Report %D 2007 %T Perturbation techniques applied to the real vanishing viscosity approximation of an initial boundary value problem %A Stefano Bianchini %I SISSA %G en %U http://preprints.sissa.it/handle/1963/35315 %1 35623 %2 Mathematics %4 1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2018-05-22T11:26:14Z No. of bitstreams: 1 boundarysingular.pdf: 312896 bytes, checksum: 59e29e4c3042b208b70e76cde63fbf32 (MD5) %0 Report %D 2007 %T Quasistatic crack growth for a cohesive zone model with prescribed crack path %A Gianni Dal Maso %A Chiara Zanini %X In this paper we study the quasistatic crack growth for a cohesive zone model. We assume that the crack path is prescribed and we study the time evolution of the crack in the framework of the variational theory of rate-independent processes. %B Proc. Roy. Soc. Edinburgh Sect. A 137 (2007) 253-279 %G en_US %U http://hdl.handle.net/1963/1686 %1 2447 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2005-06-20T12:05:32Z\\nNo. of bitstreams: 1\\nDM-Zan-04.pdf: 312529 bytes, checksum: 2373a684663d7901c85daad77c7aa8b6 (MD5) %R 10.1017/S030821050500079X %0 Journal Article %J Milan J. Math. 75 (2007) 117-134 %D 2007 %T Quasistatic evolution problems for pressure-sensitive plastic materials %A Gianni Dal Maso %A Alexey Demyanov %A Antonio DeSimone %X We study quasistatic evolution problems for pressure-sensitive plastic materials in the context of small strain associative perfect plasticity. %B Milan J. Math. 75 (2007) 117-134 %G en_US %U http://hdl.handle.net/1963/1962 %1 2231 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-05-15T10:32:12Z\\nNo. of bitstreams: 1\\nSissa27_2007M.pdf: 223083 bytes, checksum: a4cdbb7a1018403355c560749680e47a (MD5) %R 10.1007/s00032-007-0071-y %0 Journal Article %J J. Phys. A 40 (2007) 10769-10790 %D 2007 %T Reciprocal transformations and flat metrics on Hurwitz spaces %A Simonetta Abenda %A Tamara Grava %X We consider hydrodynamic systems which possess a local Hamiltonian structure of Dubrovin-Novikov type. To such a system there are also associated an infinite number of nonlocal Hamiltonian structures. We give necessary and sufficient conditions so that, after a nonlinear transformation of the independent variables, the reciprocal system still possesses a local Hamiltonian structure of Dubrovin-Novikov type. We show that, under our hypotheses, bi-hamiltonicity is preserved by the reciprocal transformation. Finally we apply such results to reciprocal systems of genus g Whitham-KdV modulation equations. %B J. Phys. A 40 (2007) 10769-10790 %G en_US %U http://hdl.handle.net/1963/2210 %1 2034 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-12T09:26:01Z\\nNo. of bitstreams: 1\\n0704.1779v2.pdf: 286756 bytes, checksum: 3d2d03a6f16be9191b242adb35638601 (MD5) %R 10.1088/1751-8113/40/35/004 %0 Report %D 2007 %T Reduced density matrices and Bose-Einstein condensation %A Alessandro Michelangeli %X Emergence and applications of the ubiquitous tool of reduced density matrices in the rigorous analysis of Bose Einstein condensation is reviewed, and new related results are added. The need and the nature of scaling limits of infinitely many particles is discussed, which imposes that a physically meaningful and mathematically well-posed definition of asymptotic condensation is placed at the level of marginals.\\nThe topic of correlations in the condensed state is addressed in order to show their influence at this level of marginals, both in the true condensed state and in the suitable trial functions one introduces to approximate the many-body structure and energy. Complete condensation is shown to be equivalently defined at any fixed k-body level, both for pure and mixed states. Further, it is proven to be equivalent to some other characterizations in terms of asymptotic factorization of the many-body state, which are currently present in the literature. %G en_US %U http://hdl.handle.net/1963/1986 %1 2210 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-08-07T12:22:30Z\\nNo. of bitstreams: 1\\n39-2007MP.pdf: 563889 bytes, checksum: b6688b840128220a2e61def6a60ff7d9 (MD5) %0 Journal Article %J Differential equations and quantum groups, IRMA Lect. Math. Theor. Phys. 9 (2007) 157-187 %D 2007 %T On the reductions and classical solutions of the Schlesinger equations %A Boris Dubrovin %A Marta Mazzocco %X The Schlesinger equations S(n,m) describe monodromy preserving\\r\\ndeformations of order m Fuchsian systems with n+1 poles. They\\r\\ncan be considered as a family of commuting time-dependent Hamiltonian\\r\\nsystems on the direct product of n copies of m×m matrix algebras\\r\\nequipped with the standard linear Poisson bracket. In this paper we address\\r\\nthe problem of reduction of particular solutions of “more complicated”\\r\\nSchlesinger equations S(n,m) to “simpler” S(n′,m′) having n′ < n\\r\\nor m′ < m. %B Differential equations and quantum groups, IRMA Lect. Math. Theor. Phys. 9 (2007) 157-187 %I SISSA %G en %U http://hdl.handle.net/1963/6472 %1 6418 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Boris Dubrovin (dubrovin@sissa.it) on 2013-02-11T14:52:15Z\\nNo. of bitstreams: 1\\ndubrovin_mazzocco_2007_irma.pdf: 300042 bytes, checksum: 85252eedf7d0fbbdf06061c20b471d44 (MD5) %0 Journal Article %J Atti .Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 18 (2007) 209-219 %D 2007 %T On the regularity of weak solutions to H-systems %A Roberta Musina %X Abstract. In this paper we prove that every weak solution to the H-surface equation is locally bounded, provided the prescibed mean curvatore H is asymptotic to a constant at infinity (with a suitable decay rate). No smoothness ssumptions are required on H. We consider also the Dirichlet problem.... %B Atti .Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 18 (2007) 209-219 %G en_US %U http://hdl.handle.net/1963/1753 %1 2791 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-20T11:28:05Z\\nNo. of bitstreams: 1\\n36M.pdf: 150157 bytes, checksum: 61fa8ec27fb7c35396978c1aa4dd26fd (MD5) %0 Journal Article %J J. Math. Phys. 48 (2007) 102102 %D 2007 %T Role of scaling limits in the rigorous analysis of Bose-Einstein condensation %A Alessandro Michelangeli %X In the context of the rigorous analysis of Bose-Einstein condensation, recent achievements have been obtained in the form of asymptotic results when some appropriate scaling is performed in the Hamiltonian, and the limit of infinite number of particles is taken. In particular, two modified thermodynamic limits of infinite dilution turned out to provide an insight in this analysis, the so-\\ncalled Gross-Pitaevskii limit and the related Tomas-Fermi limit. Here such scalings are discussed with respect to their physical and mathematical motivations, and to the currently known results obtained within this framework. %B J. Math. Phys. 48 (2007) 102102 %G en_US %U http://hdl.handle.net/1963/1984 %1 2212 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-07-26T14:30:55Z\\nNo. of bitstreams: 1\\n14-2007-MP.pdf: 485881 bytes, checksum: 3cf7764eded7853d876ad4793569bdfa (MD5) %R 10.1063/1.2783114 %0 Report %D 2007 %T Semistable principal Higgs bundles %A Ugo Bruzzo %A Beatriz Grana-Otero %G en_US %U http://hdl.handle.net/1963/2533 %1 1585 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-12-17T09:52:22Z\\nNo. of bitstreams: 1\\nPrincHiggs-2.pdf: 197562 bytes, checksum: 44797463786b3c14408f7d1898531202 (MD5) %0 Report %D 2007 %T Smooth toric DM stacks %A Barbara Fantechi %A Etienne Mann %A Fabio Nironi %X We give a new definition of smooth toric DM stacks in the same spirit of toric varieties. We show that our definition is equivalent to the one of Borisov, Chen and Smith in terms of stacky fans. In particular, we give a geometric interpretation of the combinatorial data contained in a stacky fan. We also give a bottom up classification in terms of simplicial toric varieties and fiber products of root stacks. %G en_US %U http://hdl.handle.net/1963/2120 %1 2123 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-18T06:41:10Z\\nNo. of bitstreams: 1\\ntoricarxiv.pdf: 426672 bytes, checksum: e73e63b89023046b5d53b7f7f6c2e580 (MD5) %0 Report %D 2007 %T Soft elasticity and microstructure in smectic C elastomers %A Antonio DeSimone %A James Adams %A Sergio Conti %X Smectic C elastomers are layered materials exhibiting a solid-like elastic response along the layer normal and a rubbery one in the plane. The set of strains minimizing the elastic energy contains a one-parameter family of simple stretches associated with an internal degree of freedom, coming from the in-plane component of the director. We investigate soft elasticity and the corresponding microstructure by determining the quasiconvex hull of the set , and use this to propose experimental tests that should make the predicted soft response observable. %B Contin. Mech. Thermodyn. 18 (2007) 319-334 %G en_US %U http://hdl.handle.net/1963/1811 %1 2403 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-04-12T09:42:24Z\\nNo. of bitstreams: 1\\nsissa05M-06.pdf: 394760 bytes, checksum: 95c4183d6cb1210bf2a689ae083a3cb7 (MD5) %R 10.1007/s00161-006-0031-8 %0 Journal Article %J J. Math. Anal. Appl. 335 (2007) 1143-1160 %D 2007 %T Solutions of vectorial Hamilton-Jacobi equations and minimizers of nonquasiconvex functionals %A Sandro Zagatti %X We provide a unified approach to prove existence results for the Dirichlet problem for Hamilton-Jacobi equations and for the minimum problem for nonquasiconvex functionals of the Calculus of Variations with affine boundary data. The idea relies on the definition of integro-extremal solutions introduced in the study of nonconvex scalar variational problem. %B J. Math. Anal. Appl. 335 (2007) 1143-1160 %G en_US %U http://hdl.handle.net/1963/2763 %1 1937 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-08-29T11:05:58Z\\nNo. of bitstreams: 1\\nhjcvjmaa2.pdf: 158429 bytes, checksum: 712208cb11d8543ac2f9f5f01956dcfe (MD5) %R 10.1016/j.jmaa.2007.02.034 %0 Report %D 2007 %T Solutions to the nonlinear Schroedinger equation carrying momentum along a curve. Part II: proof of the existence result %A Fethi Mahmoudi %A Andrea Malchiodi %X We prove existence of a special class of solutions to the (elliptic) Nonlinear Schroedinger Equation $- \\\\epsilon^2 \\\\Delta \\\\psi + V(x) \\\\psi = |\\\\psi|^{p-1} \\\\psi$ on a manifold or in the Euclidean space. Here V represents the potential, p is an exponent greater than 1 and $\\\\epsilon$ a small parameter corresponding to the Planck constant. As $\\\\epsilon$ tends to zero (namely in the semiclassical limit) we prove existence of complex-valued solutions which concentrate along closed curves, and whose phase in highly oscillatory. Physically, these solutions carry quantum-mechanical momentum along the limit curves. In the first part of this work we identified the limit set and constructed approximate solutions, while here we give the complete proof of our main existence result. %G en_US %U http://hdl.handle.net/1963/2111 %1 2578 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-17T08:58:17Z\\nNo. of bitstreams: 1\\n0708.0104v1.pdf: 663755 bytes, checksum: bbc4a382b0338288fa6ce9002872d955 (MD5) %0 Report %D 2007 %T Solutions to the nonlinear Schroedinger equation carrying momentum along a curve. Part I: study of the limit set and approximate solutions %A Fethi Mahmoudi %A Andrea Malchiodi %A Marcelo Montenegro %X We prove existence of a special class of solutions to the (elliptic) Nonlinear Schroeodinger Equation $- \\\\epsilon^2 \\\\Delta \\\\psi + V(x) \\\\psi = |\\\\psi|^{p-1} \\\\psi$, on a manifold or in the Euclidean space. Here V represents the potential, p an exponent greater than 1 and $\\\\epsilon$ a small parameter corresponding to the Planck constant. As $\\\\epsilon$ tends to zero (namely in the semiclassical limit) we prove existence of complex-valued solutions which concentrate along closed curves, and whose phase is highly oscillatory. Physically, these solutions carry quantum-mechanical momentum along the limit curves. In this first part we provide the characterization of the limit set, with natural stationarity and non-degeneracy conditions. We then construct an approximate solution up to order $\\\\epsilon^2$, showing that these conditions appear naturally in a Taylor expansion of the equation in powers of $\\\\epsilon$. Based on these, an existence result will be proved in the second part. %G en_US %U http://hdl.handle.net/1963/2112 %1 2577 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-17T09:14:27Z\\nNo. of bitstreams: 1\\n0708.0125v1.pdf: 498331 bytes, checksum: 95036be8fb1f07136be4d6bdc1aab642 (MD5) %0 Journal Article %J Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 18 (2007) 391-412 %D 2007 %T Some existence results for the Toda system on closed surfaces %A Andrea Malchiodi %A Cheikh Birahim Ndiaye %X Given a compact closed surface $\\\\Sig$, we consider the {\\\\em generalized Toda} system of equations on $\\\\Sig$: $- \\\\D u_i = \\\\sum_{j=1}^2 \\\\rho_j a_{ij} \\\\left( \\\\frac{h_j e^{u_j}}{\\\\int_\\\\Sig h_j e^{u_j} dV_g} - 1 \\\\right)$ for $i = 1, 2$, where $\\\\rho_1, \\\\rho_2$ are real parameters and $h_1, h_2$ are smooth positive functions. Exploiting the variational structure of the problem and using a new minimax scheme we prove existence of solutions for generic values of $\\\\rho_1$ and for $\\\\rho_2 < 4 \\\\pi$. %B Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 18 (2007) 391-412 %G en_US %U http://hdl.handle.net/1963/1775 %1 2769 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-29T08:29:06Z\\nNo. of bitstreams: 1\\n75M.pdf: 258110 bytes, checksum: 18821ff73b71e5079c15c32f59961ad9 (MD5) %R 10.4171/RLM/504 %0 Journal Article %J NoDEA Nonlinear Differential Equations Appl. 14 (2007) 569-592 %D 2007 %T Stability of front tracking solutions to the initial and boundary value problem for systems of conservation laws %A Andrea Marson %A Carlotta Donadello %B NoDEA Nonlinear Differential Equations Appl. 14 (2007) 569-592 %G en_US %U http://hdl.handle.net/1963/1769 %1 2775 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-28T10:29:02Z\\nNo. of bitstreams: 1\\n68M.pdf: 209186 bytes, checksum: 79dcb94eb1405cbadb411592b2cffe66 (MD5) %R 10.1007/s00030-007-5010-7 %0 Report %D 2007 %T Standing waves of some coupled Nonlinear Schrödinger Equations %A Antonio Ambrosetti %A Eduardo Colorado %X We deal with a class of systems of NLS equations, proving the existence of bound and ground states provided the coupling parameter is small, respectively, large. %B J. Lond. Math. Soc. 75 (2007) 67-82 %G en_US %U http://hdl.handle.net/1963/1821 %1 2393 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-04-18T14:55:22Z\\nNo. of bitstreams: 1\\nsissa,2_2006_M.pdf: 431407 bytes, checksum: 0e294e77a4423c4b41ce178df2187dd3 (MD5) %R 10.1112/jlms/jdl020 %0 Report %D 2007 %T Strengthened convergence of marginals to the cubic nonlinear Schroedinger equation %A Alessandro Michelangeli %X We rewrite a recent derivation of the cubic non-linear Schroedinger equation by Adami, Golse, and Teta in the more natural formof the asymptotic factorisation of marginals at any fixed time and in the trace norm. This is the standard form in which the emergence of the\\nnon-linear effective dynamics of a large system of interacting bosons is\\nproved in the literature. %G en_US %U http://hdl.handle.net/1963/1977 %1 2218 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-06-06T09:21:56Z\\nNo. of bitstreams: 1\\nstrengthened.pdf: 228368 bytes, checksum: c87b1b3ae8fd722412cf906c5f44df5b (MD5) %0 Journal Article %J Arch. Rational Mech. Anal. 183 (2007) 411-456 %D 2007 %T Surfactants in Foam Stability: A Phase-Field Model %A Irene Fonseca %A Massimiliano Morini %A Valeriy Slastikov %X The role of surfactants in stabilizing the formation of bubbles in foams is studied using a phase-field model. The analysis is centered on a van der Walls-Cahn-Hilliard-type energy with an added term accounting for the interplay between the presence of a surfactant density and the creation of interfaces. In particular, it is concluded that the surfactant segregates to the interfaces, and that the prescriptionof the distribution of surfactant will dictate the locus of interfaces, what is in agreement with experimentation. %B Arch. Rational Mech. Anal. 183 (2007) 411-456 %G en_US %U http://hdl.handle.net/1963/2035 %1 2161 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-03T15:51:40Z\\nNo. of bitstreams: 1\\n05-CNA-012.pdf: 414998 bytes, checksum: 3c44841388edba53080d531beadad798 (MD5) %R 10.1007/s00205-006-0012-x %0 Journal Article %J 46th IEEE Conference on Decision and Control (2007) 5389 - 5394 %D 2007 %T Time optimal swing-up of the planar pendulum %A Mireille E. Broucke %A Paolo Mason %A Benedetto Piccoli %X This paper presents qualitative and numerical results on the global structure of the time optimal trajectories of the planar pendulum on a cart. %B 46th IEEE Conference on Decision and Control (2007) 5389 - 5394 %G en_US %U http://hdl.handle.net/1963/1867 %1 2355 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-10-11T06:54:22Z\\nNo. of bitstreams: 1\\n50-2006M.pdf: 688756 bytes, checksum: d32f46138cc2e7400dfec38315fdb24a (MD5) %R 10.1109/CDC.2007.4434688 %0 Report %D 2007 %T Time-dependent systems of generalized Young measures %A Gianni Dal Maso %A Antonio DeSimone %A Maria Giovanna Mora %A Massimiliano Morini %X In this paper some new tools for the study of evolution problems in the framework of Young measures are introduced. A suitable notion of time-dependent system of generalized Young measures is defined, which allows to extend the classical notions of total variation and absolute continuity with respect to time, as well as the notion of time derivative. The main results are a Helly type theorem for sequences of systems of generalized Young measures and a theorem about the existence of the time derivative for systems with bounded variation with respect to time. %B Netw. Heterog. Media 2 (2007) 1-36 %G en_US %U http://hdl.handle.net/1963/1795 %1 2749 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-04-04T13:16:42Z\\nNo. of bitstreams: 1\\n98M-2005.pdf: 339547 bytes, checksum: 695874ce74733dc0020a7e357f04cb1b (MD5) %0 Report %D 2007 %T Twisted noncommutative equivariant %A Lucio Cirio %X We propose Weil and Cartan models for the equivariant cohomology of covariant actions on toric deformation manifolds. The construction is based on the noncommutative Weil algebra of Alekseev and Meinrenken; we show that one can implement a Drinfeld twist of their models in order to take into account the noncommutativity of the spaces we are acting on. %G en_US %U http://hdl.handle.net/1963/1991 %1 2205 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-08-09T12:36:58Z\\nNo. of bitstreams: 1\\nmathQA0706.3602v2.pdf: 303765 bytes, checksum: 74571e1a7df81268457a3ae54726fd75 (MD5) %0 Journal Article %J J. Convex Anal. 14 (2007) 705-727 %D 2007 %T Uniqueness and continuous dependence on boundary data for integro-extremal minimizers of the functional of the gradient %A Sandro Zagatti %X We study some qualitative properties of the integro-extremal minimizers of the functional of the gradient defined on Sobolev spaces with Dirichlet boundary conditions. We discuss their use in the non-convex case via viscosity methods and give conditions under which they are unique and depend continuously on boundary data. %B J. Convex Anal. 14 (2007) 705-727 %G en_US %U http://hdl.handle.net/1963/2762 %1 1938 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-08-29T10:56:35Z\\nNo. of bitstreams: 1\\nwpca3.pdf: 193462 bytes, checksum: 05e86c2307278ebd530e02f2baf5072e (MD5) %0 Journal Article %J J. Hyperbolic Differ. Equ. 4 (2007) 771-795 %D 2007 %T Viscosity solutions of Hamilton-Jacobi equations with discontinuous coefficients %A Giuseppe Maria Coclite %A Nils Henrik Risebro %X We consider Hamilton--Jacobi equations, where the Hamiltonian depends discontinuously on both the spatial and temporal location. Our main results are the existence and well--posedness of a viscosity solution to the Cauchy problem. We define a viscosity solution by treating the discontinuities in the coefficients analogously to \\\"internal boundaries\\\". By defining an appropriate penalization function, we prove that viscosity solutions are unique. The existence of viscosity solutions is established by showing that a sequence of front tracking approximations is compact in $L^\\\\infty$, and that the limits are viscosity solutions. %B J. Hyperbolic Differ. Equ. 4 (2007) 771-795 %I World Scientific %G en_US %U http://hdl.handle.net/1963/2907 %1 1793 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-11T10:55:33Z\\nNo. of bitstreams: 1\\nmath.AP0303288.pdf: 286583 bytes, checksum: ec274415af1f87dc1406bdc76cab8159 (MD5) %R 10.1142/S0219891607001355 %0 Journal Article %J Calc. Var. Partial Differential Equations 27 (2006) 233-253 %D 2006 %T 2-d stability of the Néel wall %A Antonio DeSimone %A Hans Knuepfer %A Felix Otto %X We are interested in thin-film samples in micromagnetism, where the magnetization m is a 2-d unit-length vector field. More precisely we are interested in transition layers which connect two opposite magnetizations, so called Néel walls. %B Calc. Var. Partial Differential Equations 27 (2006) 233-253 %G en_US %U http://hdl.handle.net/1963/2194 %1 2050 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-10T12:14:45Z\\nNo. of bitstreams: 1\\nstability.pdf: 226255 bytes, checksum: dec90ada941ac865d9451848ca2faa5f (MD5) %R 10.1007/s00526-006-0019-z %0 Journal Article %J Phys. Rev. B 73 (2006) 100502(R) %D 2006 %T 4e-condensation in a fully frustrated Josephson junction diamond chain %A Matteo Rizzi %A Vittorio Cataudella %A Rosario Fazio %X Fully frustrated one-dimensional diamond Josephson chains have been shown [B. Dou\\\\c{c}ot and J. Vidal, Phys. Rev. Lett. {\\\\bf 88}, 227005 (2002)] to posses a remarkable property: The superfluid phase occurs through the condensation of pairs of Cooper pairs. By means of Monte Carlo simulations we analyze quantitatively the Insulator to $4e$-Superfluid transition. We determine the location of the critical point and discuss the behaviour of the phase-phase correlators. For comparison we also present the case of a diamond chain at zero and 1/3 frustration where the standard $2e$-condensation is observed. %B Phys. Rev. B 73 (2006) 100502(R) %G en_US %U http://hdl.handle.net/1963/2400 %1 2297 %2 Physics %3 Condensed Matter Theory %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-11-13T08:27:31Z\\nNo. of bitstreams: 1\\n0511423v1.pdf: 197406 bytes, checksum: 754c3576bbb6a549f4dac12eeb8fc92d (MD5) %R 10.1103/PhysRevB.73.100502 %0 Report %D 2006 %T Almost Global Stochastic Feedback Stabilization of Conditional Quantum Dynamics %A Claudio Altafini %A Francesco Ticozzi %X We propose several parametrization-free solutions to the problem of quantum state reduction control by means of continuous measurement and smooth quantum feedback. In particular, we design a feedback law for which almost global stochastic feedback stabilization can be proved analytically by means of Lyapunov techinques. This synthesis arises very naturally from the physics of the problem, as it relies on the variance associated with the quantum filtering process. %G en_US %U http://hdl.handle.net/1963/1727 %1 2424 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-01-30T12:56:41Z\\nNo. of bitstreams: 1\\nquant-ph0510222.pdf: 574764 bytes, checksum: d53ebd4e4afe123a6476bed544c4b9df (MD5) %0 Report %D 2006 %T An artificial viscosity approach to quasistatic crack growth %A Rodica Toader %A Chiara Zanini %X We introduce a new model of irreversible quasistatic crack growth in which the evolution of cracks is the limit of a suitably modified $\\\\epsilon$-gradient flow of the energy functional, as the \\\"viscosity\\\" parameter $\\\\epsilon$ tends to zero. %G en_US %U http://hdl.handle.net/1963/1850 %1 2367 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-07-26T10:13:38Z\\nNo. of bitstreams: 1\\nmath.AP-0607596.pdf: 297980 bytes, checksum: 7a13d5d5fe36a4577923b3ccd0b0acaf (MD5) %0 Journal Article %J SIAM J. Math. Anal. 37 (2006) 83-102 %D 2006 %T A Birkhoff-Lewis-Type Theorem for Some Hamiltonian PDEs %A Dario Bambusi %A Massimiliano Berti %X In this paper we give an extension of the Birkhoff--Lewis theorem to some semilinear PDEs. Accordingly we prove existence of infinitely many periodic orbits with large period accumulating at the origin. Such periodic orbits bifurcate from resonant finite dimensional invariant tori of the fourth order normal form of the system. Besides standard nonresonance and nondegeneracy assumptions, our main result is obtained assuming a regularizing property of the nonlinearity. We apply our main theorem to a semilinear beam equation and to a nonlinear Schr\\\\\\\"odinger equation with smoothing nonlinearity. %B SIAM J. Math. Anal. 37 (2006) 83-102 %G en_US %U http://hdl.handle.net/1963/2159 %1 2085 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-02T09:24:09Z\\nNo. of bitstreams: 1\\n0310182v1.pdf: 221749 bytes, checksum: 1ca47fecc44576d771b14ead5f53db0e (MD5) %R 10.1137/S0036141003436107 %0 Report %D 2006 %T Born approximation in the problem of the rigorous derivation of the Gross-Pitaevskii equation %A Alessandro Michelangeli %X \\\"It has a flavour of Mathematical Physics...\\\"With these words, just few years ago, prof. Di Giacomo\\nused to introduce the topic of the Born approximation within a nonrelativistic potential theory, in his `oversize\\\' course of Theoretical Physics in Pisa. Something maybe too fictitious inside the formal theory of the scattering he was teaching us at that point of the course. Now that I\\\'m (studying to become) a Mathematical Physicist indeed, dealing with such an `exotic tasting\\\' topic, those words come back to the mind, into a new perspective. Here the very recent problem of the rigorous derivation of\\nthe cubic nonlinear Schrödinger equation (the Gross-Pitaevskiî equation) is reviewed and discussed, with respect to the role of the Born approximation that one ends up with in an appropriate scaling limit %G en_US %U http://hdl.handle.net/1963/1819 %1 2395 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-04-18T13:24:51Z\\nNo. of bitstreams: 1\\nSISSA13-2006FM.pdf: 154961 bytes, checksum: 6a952a2dc9b448e8b3476560ad108a93 (MD5) %0 Journal Article %J C. R. Acad. Sci. Paris, Ser. I 342 (2006) 453-458 %D 2006 %T Bound and ground states of coupled nonlinear Schrödinger equations %A Antonio Ambrosetti %A Eduardo Colorado %X We prove existence of bound and ground states of some systems of coupled nonlinear Schrodinger equations. %B C. R. Acad. Sci. Paris, Ser. I 342 (2006) 453-458 %G en_US %U http://hdl.handle.net/1963/2149 %1 2094 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-28T10:05:04Z\\nNo. of bitstreams: 1\\nAmbrosettiColorado05.pdf: 205538 bytes, checksum: 7ada83c882cd1488c72316a917a79c87 (MD5) %R 10.1016/j.crma.2006.01.024 %0 Journal Article %J J. Anal. Math. 98 (2006) 317-348 %D 2006 %T Bound states of Nonlinear Schroedinger Equations with Potentials Vanishing at Infinity %A Antonio Ambrosetti %A Andrea Malchiodi %A David Ruiz %B J. Anal. Math. 98 (2006) 317-348 %G en_US %U http://hdl.handle.net/1963/1756 %1 2788 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-21T12:13:53Z\\nNo. of bitstreams: 1\\n18M-2005.pdf: 300610 bytes, checksum: cf46904521c6dfea82ac4f4516bc9fe0 (MD5) %R 10.1007/BF02790279 %0 Journal Article %J Self-Similar Solutions of Nonlinear PDE / Ed. Piotr Biler and Grzegorz Karch. - Banach Center Publ. 74 (2006) 13-31 %D 2006 %T On Bressan\\\'s conjecture on mixing properties of vector fields %A Stefano Bianchini %B Self-Similar Solutions of Nonlinear PDE / Ed. Piotr Biler and Grzegorz Karch. - Banach Center Publ. 74 (2006) 13-31 %G en_US %U http://hdl.handle.net/1963/1806 %1 2408 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-04-06T13:44:58Z\\nNo. of bitstreams: 1\\n70M.pdf: 252974 bytes, checksum: 6abff10ab36790484305a3078d9cbfd7 (MD5) %0 Report %D 2006 %T On a Camassa-Holm type equation with two dependent variables %A Gregorio Falqui %X We consider a generalization of the Camassa Holm (CH) equation with two dependent variables, called CH2, introduced in [16]. We briefly provide an alternative derivation of it based on the theory of Hamiltonian structures\\non (the dual of) a Lie Algebra. The Lie Algebra here involved is the same algebra underlying the NLS hierarchy. We study the structural properties of the CH2 hierarchy within the bihamiltonian theory of integrable PDEs, and\\nprovide its Lax representation. Then we explicitly discuss how to construct classes of solutions, both of peakon and of algebro-geometrical type. We finally sketch the construction of a class of singular solutions, defined by setting to zero one of the two dependent variables. %B J. Phys. A 39 (2006) 327-342 %G en_US %U http://hdl.handle.net/1963/1721 %1 2430 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-01-24T09:13:43Z\\nNo. of bitstreams: 1\\nnlin.SI0505059.pdf: 237623 bytes, checksum: cb1fb914c67ff1b46cf842d1c6853364 (MD5) %R 10.1088/0305-4470/39/2/004 %0 Report %D 2006 %T A Canonical Frame for Nonholonomic Rank Two Distributions of Maximal Class %A Boris Doubrov %A Igor Zelenko %X In 1910 E. Cartan constructed the canonical frame and found the most symmetric case for maximally nonholonomic rank 2 distributions in R5. We solve the analogous problems for rank 2 distributions in Rn for arbitrary n > 5. Our method is a kind of symplectification of the problem and it is completely different from the Cartan method of equivalence. %B C. R. Math. Acad. Sci. Paris 342 (2006) 589-594 %G en_US %U http://hdl.handle.net/1963/1712 %1 2439 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-01-18T10:08:04Z\\nNo. of bitstreams: 1\\nmath.DG0504319.pdf: 158321 bytes, checksum: 4a76e9fa42a9ea4440d0fcd628df9c34 (MD5) %R 10.1016/j.crma.2006.02.010 %0 Journal Article %J Duke Math. J. 134 (2006) 359-419 %D 2006 %T Cantor families of periodic solutions for completely resonant nonlinear wave equations %A Massimiliano Berti %A Philippe Bolle %X We prove the existence of small amplitude, $2\\\\pi \\\\slash \\\\om$-periodic in time solutions of completely resonant nonlinear wave equations with Dirichlet boundary conditions, for any frequency $ \\\\om $ belonging to a Cantor-like set of positive measure and for a new set of nonlinearities. The proof relies on a suitable Lyapunov-Schmidt decomposition and a variant of the Nash-Moser Implicit Function Theorem. In spite of the complete resonance of the equation we show that we can still reduce the problem to a {\\\\it finite} dimensional bifurcation equation. Moreover, a new simple approach for the inversion of the linearized operators required by the Nash-Moser scheme is developed. It allows to deal also with nonlinearities which are not odd and with finite spatial regularity. %B Duke Math. J. 134 (2006) 359-419 %G en_US %U http://hdl.handle.net/1963/2161 %1 2083 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-02T09:53:35Z\\nNo. of bitstreams: 1\\n0410618v1.pdf: 427752 bytes, checksum: 08750b5fadd830fbe76aa48d54824f17 (MD5) %R 10.1215/S0012-7094-06-13424-5 %0 Journal Article %J J. Math. Sci. 135 (2006) 3109-3124 %D 2006 %T Classification of stable time-optimal controls on 2-manifolds %A Ugo Boscain %A Igor Nikolaev %A Benedetto Piccoli %B J. Math. Sci. 135 (2006) 3109-3124 %G en_US %U http://hdl.handle.net/1963/2196 %1 2048 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-11T07:48:50Z\\nNo. of bitstreams: 1\\nboscain-paper.pdf: 322031 bytes, checksum: 560c6fdce3f93d196d1cc9d9c4115edb (MD5) %R 10.1007/s10958-006-0148-0 %0 Journal Article %J SIAM J. Control Optim. 45 (2006) 226-245 %D 2006 %T Common Polynomial Lyapunov Functions for Linear Switched Systems %A Paolo Mason %A Ugo Boscain %A Yacine Chitour %X In this paper, we consider linear switched systems $\\\\dot x(t)=A_{u(t)} x(t)$, $x\\\\in\\\\R^n$, $u\\\\in U$, and the problem of asymptotic stability for arbitrary switching functions, uniform with respect to switching ({\\\\bf UAS} for short). We first prove that, given a {\\\\bf UAS} system, it is always possible to build a common polynomial Lyapunov function. Then our main result is that the degree of that common polynomial Lyapunov function is not uniformly bounded over all the {\\\\bf UAS} systems. This result answers a question raised by Dayawansa and Martin. A generalization to a class of piecewise-polynomial Lyapunov functions is given. %B SIAM J. Control Optim. 45 (2006) 226-245 %G en_US %U http://hdl.handle.net/1963/2181 %1 2063 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-04T14:36:21Z\\nNo. of bitstreams: 1\\n0403209v2.pdf: 244831 bytes, checksum: 1762d79876f9eb915a68dbc25d9a3a21 (MD5) %R 10.1137/040613147 %0 Journal Article %J J. Reine Angew. Math. 594 (2006) 137-174 %D 2006 %T Compactness of solutions to some geometric fourth-order equations %A Andrea Malchiodi %X We prove compactness of solutions to some fourth order equations with exponential nonlinearities on four manifolds. The proof is based on a refined bubbling analysis, for which the main estimates are given in integral form. Our result is used in a subsequent paper to find critical points (via minimax arguments) of some geometric functional, which give rise to conformal metrics of constant $Q$-curvature. As a byproduct of our method, we also obtain compactness of such metrics. %B J. Reine Angew. Math. 594 (2006) 137-174 %G en_US %U http://hdl.handle.net/1963/2126 %1 2117 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-18T08:13:05Z\\nNo. of bitstreams: 1\\n0410140v2.pdf: 335757 bytes, checksum: 30341fcdac6b4d8f187b4bab1191c993 (MD5) %R 10.1515/CRELLE.2006.038 %0 Journal Article %J Atti Accad. Naz Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 17 (2006) 279-290 %D 2006 %T Concentration at manifolds of arbitrary dimension for a singularly perturbed Neumann problem %A Fethi Mahmoudi %A Andrea Malchiodi %X We consider the equation $- \\\\e^2 \\\\D u + u = u^p$ in $\\\\O \\\\subseteq \\\\R^N$, where $\\\\O$ is open, smooth and bounded, and we prove concentration of solutions along $k$-dimensional minimal submanifolds of $\\\\pa \\\\O$, for $N \\\\geq 3$ and for $k \\\\in \\\\{1, \\\\dots, N-2\\\\}$. We impose Neumann boundary conditions, assuming $1<\\\\frac{N-k+2}{N-k-2}$ and $\\\\e \\\\to 0^+$. This result settles in full generality a phenomenon previously considered only in the particular case $N = 3$ and $k = 1$. %B Atti Accad. Naz Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 17 (2006) 279-290 %G en_US %U http://hdl.handle.net/1963/2170 %1 2074 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-03T12:23:19Z\\nNo. of bitstreams: 1\\nMahmoudiMalchiodi06.pdf: 624613 bytes, checksum: 030160de63323a3b0c3864b8f5102b0b (MD5) %0 Journal Article %J Comm. Math. Phys. 266 (2006) 471-497 %D 2006 %T Conservative Solutions to a Nonlinear Variational Wave Equation %A Alberto Bressan %A Zheng Yuxi %X We establish the existence of a conservative weak solution to the Cauchy problem for the nonlinear variational wave equation $u_{tt} - c(u)(c(u)u_x)_x=0$, for initial data of finite energy. Here $c(\\\\cdot)$ is any smooth function with uniformly positive bounded values. %B Comm. Math. Phys. 266 (2006) 471-497 %G en_US %U http://hdl.handle.net/1963/2184 %1 2060 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-05T08:06:00Z\\nNo. of bitstreams: 1\\n0502058v1.pdf: 265359 bytes, checksum: 77983b4834210b17aa4c758dbf189d4a (MD5) %R 10.1007/s00220-006-0047-8 %0 Journal Article %J Int. J. Mod. Phys. A 21 (2006) 3133-3150 %D 2006 %T A cyclic integral on k-Minkowski noncommutative space-time %A Alessandra Agostini %A Giovanni Amelino-Camelia %A Michele Arzano %A Francesco D\'Andrea %X We examine some alternative possibilities for an action functional for $\\\\kappa$-Minkowski noncommutative spacetime, with an approach which should be applicable to other spacetimes with coordinate-dependent commutators of the spacetime coordinates ($[x_\\\\mu,x_\\\\nu]=f_{\\\\mu,\\\\nu}(x)$). Early works on $\\\\kappa$-Minkowski focused on $\\\\kappa$-Poincar\\\\\\\'e covariance and the dependence of the action functional on the choice of Weyl map, renouncing to invariance under cyclic permutations of the factors composing the argument of the action functional. A recent paper (hep-th/0307149), by Dimitrijevic, Jonke, Moller, Tsouchnika, Wess and Wohlgenannt, focused on a specific choice of Weyl map and, setting aside the issue of $\\\\kappa$-Poincar\\\\\\\'e covariance of the action functional, introduced in implicit form a cyclicity-inducing measure. We provide an explicit formula for (and derivation of) a choice of measure which indeed ensures cyclicity of the action functional, and we show that the same choice of measure is applicable to all the most used choices of Weyl map. We find that this ``cyclicity-inducing measure\\\'\\\' is not covariant under $\\\\kappa$-Poincar\\\\\\\'e transformations. We also notice that the cyclicity-inducing measure can be straightforwardly derived using a map which connects the $\\\\kappa$-Minkowski spacetime coordinates and the spacetime coordinates of a ``canonical\\\'\\\' noncommutative spacetime, with coordinate-independent commutators. %B Int. J. Mod. Phys. A 21 (2006) 3133-3150 %G en_US %U http://hdl.handle.net/1963/2158 %1 2086 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-02T08:56:14Z\\nNo. of bitstreams: 1\\n0407227v1.pdf: 219700 bytes, checksum: 4a7f6665bddfb66793e39aa4a8e3ce25 (MD5) %R 10.1142/S0217751X06031077 %0 Journal Article %J Arch. Ration. Mech. Anal. 181 (2006) 1-42 %D 2006 %T The Dirichlet problem for H-systems with small boundary data: blowup phenomena and nonexistence results %A Paolo Caldiroli %A Roberta Musina %B Arch. Ration. Mech. Anal. 181 (2006) 1-42 %G en_US %U http://hdl.handle.net/1963/2252 %1 1995 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-18T07:32:51Z\\nNo. of bitstreams: 1\\nCaldiroliMusina04.pdf: 395788 bytes, checksum: f37ad36b2fc2eb85d6430053a575ed8c (MD5) %R 10.1007/s00205-005-0398-x %0 Journal Article %J ESAIM Control Optim. Calc. Var. 12 (2006) 409-441 %D 2006 %T An estimation of the controllability time for single-input systems on compact Lie Groups %A Andrei Agrachev %A Thomas Chambrion %X Geometric control theory and Riemannian techniques are used to describe the reachable set at time t of left invariant single-input control systems on semi-simple compact Lie groups and to estimate the minimal time needed to reach any point from identity. This method provides an effective way to give an upper and a lower bound for the minimal time needed to transfer a controlled quantum system with a drift from a given initial position to a given final position. The bounds include diameters of the flag manifolds; the latter are also explicitly computed in the paper. %B ESAIM Control Optim. Calc. Var. 12 (2006) 409-441 %G en_US %U http://hdl.handle.net/1963/2135 %1 2108 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-24T13:09:42Z\\nNo. of bitstreams: 1\\ncocv0452.pdf: 441157 bytes, checksum: 7c8ead7c835051e17567fe9bb8a60fbe (MD5) %R 10.1051/cocv:2006007 %0 Journal Article %J Molecular pharmacology. 2006 Jul; 70(1):373-82 %D 2006 %T Experimental and modeling studies of desensitization of P2X3 receptors. %A Elena Sokolova %A Andrei Skorinkin %A Igor Moiseev %A Andrei Agrachev %A Andrea Nistri %A Rashid Giniatullin %X The function of ATP-activated P2X3 receptors involved in pain sensation is modulated by desensitization, a phenomenon poorly understood. The present study used patch-clamp recording from cultured rat or mouse sensory neurons and kinetic modeling to clarify the properties of P2X3 receptor desensitization. Two types of desensitization were observed, a fast process (t1/2 = 50 ms; 10 microM ATP) following the inward current evoked by micromolar agonist concentrations, and a slow process (t1/2 = 35 s; 10 nM ATP) that inhibited receptors without activating them. We termed the latter high-affinity desensitization (HAD). Recovery from fast desensitization or HAD was slow and agonist-dependent. When comparing several agonists, there was analogous ranking order for agonist potency, rate of desensitization and HAD effectiveness, with 2-methylthioadenosine triphosphate the strongest and beta,gamma-methylene-ATP the weakest. HAD was less developed with recombinant (ATP IC50 = 390 nM) than native P2X3 receptors (IC50 = 2.3 nM). HAD could also be induced by nanomolar ATP when receptors seemed to be nondesensitized, indicating that resting receptors could express high-affinity binding sites. Desensitization properties were well accounted for by a cyclic model in which receptors could be desensitized from either open or closed states. Recovery was assumed to be a multistate process with distinct kinetics dependent on the agonist-dependent dissociation rate from desensitized receptors. Thus, the combination of agonist-specific mechanisms such as desensitization onset, HAD, and resensitization could shape responsiveness of sensory neurons to P2X3 receptor agonists. By using subthreshold concentrations of an HAD-potent agonist, it might be possible to generate sustained inhibition of P2X3 receptors for controlling chronic pain. %B Molecular pharmacology. 2006 Jul; 70(1):373-82 %I the American Society for Pharmacology and Experimental Therapeutics %G en %U http://hdl.handle.net/1963/4974 %1 4799 %2 Neuroscience %3 Neurobiology %4 -1 %$ Submitted by Alireza Alemi-neissi (alemi@sissa.it) on 2011-10-30T18:23:32Z\\nNo. of bitstreams: 0 %R 10.1124/mol.106.023564 %0 Report %D 2006 %T Extended affine Weyl groups and Frobenius manifolds -- II %A Boris Dubrovin %A Zhang Youjin %A Zuo Dafeng %X For the root system of type $B_l$ and $C_l$, we generalize the result of \\\\cite{DZ1998} by showing the existence of a Frobenius manifold structure on the orbit space of the extended affine Weyl group that corresponds to any vertex of the Dynkin diagram instead of a particular choice of \\\\cite{DZ1998}. %G en_US %U http://hdl.handle.net/1963/1787 %1 2757 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-30T13:34:27Z\\nNo. of bitstreams: 1\\n90FM-2005.pdf: 254524 bytes, checksum: abdf833c0cf0b01fb79663489dd6acc2 (MD5) %0 Journal Article %J Ann. Inst. H. Poincaré Anal. Non Linéaire 23 (2006) 439-474 %D 2006 %T Forced vibrations of wave equations with non-monotone nonlinearities %A Massimiliano Berti %A Luca Biasco %X We prove existence and regularity of periodic in time solutions of completely resonant nonlinear forced wave equations with Dirichlet boundary conditions for a large class of non-monotone forcing terms. Our approach is based on a variational Lyapunov-Schmidt reduction. It turns out that the infinite dimensional bifurcation equation exhibits an intrinsic lack of compactness. We solve it via a minimization argument and a-priori estimate methods inspired to regularity theory of Rabinowitz. %B Ann. Inst. H. Poincaré Anal. Non Linéaire 23 (2006) 439-474 %G en_US %U http://hdl.handle.net/1963/2160 %1 2084 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-02T09:35:53Z\\nNo. of bitstreams: 1\\n0410619v1.pdf: 401724 bytes, checksum: 1aeb5616e38d96fffc8efa0b0e6cdc14 (MD5) %R 10.1016/j.anihpc.2005.05.004 %0 Journal Article %J J. Dyn. Control Syst. 12 (2006) 247-276 %D 2006 %T Fundamental form and Cartan tensor of (2,5)-distributions coincide %A Igor Zelenko %X In our previous paper for generic rank 2 vector distributions on n-dimensional manifold (n greater or equal to 5) we constructed a special differential invariant, the fundamental form. In the case n=5 this differential invariant has the same algebraic nature, as the covariant binary biquadratic form, constructed by E.Cartan in 1910, using his ``reduction- prolongation\\\'\\\' procedure (we call this form Cartan\\\'s tensor). In the present paper we prove that our fundamental form coincides (up to constant factor -35) with Cartan\\\'s tensor. This result explains geometric reason for existence of Cartan\\\'s tensor (originally this tensor was obtained by very sophisticated algebraic manipulations) and gives the true analogs of this tensor in Riemannian geometry. In addition, as a part of the proof, we obtain a new useful formula for Cartan\\\'s tensor in terms of structural functions of any frame naturally adapted to the distribution. %B J. Dyn. Control Syst. 12 (2006) 247-276 %G en_US %U http://hdl.handle.net/1963/2187 %1 2057 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-05T10:55:36Z\\nNo. of bitstreams: 1\\n0402195v2.pdf: 284986 bytes, checksum: dae1f8053a160dbaf2913b802569c21a (MD5) %R 10.1007/s10450-006-0383-1 %0 Journal Article %J J. Math. Sci. 135 (2006) 3168-3194 %D 2006 %T On geodesic equivalence of Riemannian metrics and sub-Riemannian metrics on distributions of corank 1 %A Igor Zelenko %X The present paper is devoted to the problem of (local) geodesic equivalence of Riemannian metrics and sub-Riemannian metrics on generic corank 1 distributions. Using Pontryagin Maximum Principle, we treat Riemannian and sub-Riemannian cases in an unified way and obtain some algebraic necessary conditions for the geodesic equivalence of (sub-)Riemannian metrics. In this way first we obtain a new elementary proof of classical Levi-Civita\\\'s Theorem about the classification of all Riemannian geodesically equivalent metrics in a neighborhood of so-called regular (stable) point w.r.t. these metrics. Secondly we prove that sub-Riemannian metrics on contact distributions are geodesically equivalent iff they are constantly proportional. Then we describe all geodesically equivalent sub-Riemannian metrics on quasi-contact distributions. Finally we make the classification of all pairs of geodesically equivalent Riemannian metrics on a surface, which proportional in an isolated point. This is the simplest case, which was not covered by Levi-Civita\\\'s Theorem. %B J. Math. Sci. 135 (2006) 3168-3194 %G en_US %U http://hdl.handle.net/1963/2205 %1 2039 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-11T13:59:27Z\\nNo. of bitstreams: 1\\n0406111v1.pdf: 375215 bytes, checksum: cc4213e75a28857f98f01a294abff5e0 (MD5) %R 10.1007/s10958-006-0151-5 %0 Report %D 2006 %T Glimm interaction functional for BGK schemes %A Stefano Bianchini %G en_US %U http://hdl.handle.net/1963/1770 %1 2774 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-28T10:37:13Z\\nNo. of bitstreams: 1\\n69M.pdf: 213784 bytes, checksum: 597991852480bdc1aed7ed05ecc610c5 (MD5) %0 Report %D 2006 %T On Hamiltonian perturbations of hyperbolic systems of conservation laws, II: universality of critical behaviour %A Boris Dubrovin %X Hamiltonian perturbations of the simplest hyperbolic equation $u_t + a(u) u_x=0$ are studied. We argue that the behaviour of solutions to the perturbed equation near the point of gradient catastrophe of the unperturbed one should be essentially independent on the choice of generic perturbation neither on the choice of generic solution. Moreover, this behaviour is described by a special solution to an integrable fourth order ODE. %B Comm. Math. Phys. 267 (2006) 117-139 %G en_US %U http://hdl.handle.net/1963/1786 %1 2758 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-30T13:22:52Z\\nNo. of bitstreams: 1\\n89FM-2005.pdf: 250067 bytes, checksum: 1e057f524c879ec57fa25833b141b6b6 (MD5) %R 10.1007/s00220-006-0021-5 %0 Journal Article %J Comm. Pure Appl. Math. 59 (2006) 559-615 %D 2006 %T On Hamiltonian perturbations of hyperbolic systems of conservation laws I: quasitriviality of bihamiltonian perturbations %A Boris Dubrovin %A Liu Si-Qi %A Zhang Youjin %X We study the general structure of formal perturbative solutions to the Hamiltonian perturbations of spatially one-dimensional systems of hyperbolic PDEs. Under certain genericity assumptions it is proved that any bihamiltonian perturbation can be eliminated in all orders of the perturbative expansion by a change of coordinates on the infinite jet space depending rationally on the derivatives. The main tools is in constructing of the so-called quasi-Miura transformation of jet coordinates eliminating an arbitrary deformation of a semisimple bihamiltonian structure of hydrodynamic type (the quasitriviality theorem). We also describe, following \\\\cite{LZ1}, the invariants of such bihamiltonian structures with respect to the group of Miura-type transformations depending polynomially on the derivatives. %B Comm. Pure Appl. Math. 59 (2006) 559-615 %G en_US %U http://hdl.handle.net/1963/2535 %1 1583 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-12-18T13:01:41Z\\nNo. of bitstreams: 1\\n0410027v2.pdf: 508002 bytes, checksum: 4e8fc8db5fc7512dd54eb832cc52192d (MD5) %R 10.1002/cpa.20111 %0 Journal Article %J IEEE Trans. Automat. Control 51 (2006) 1566-1571 %D 2006 %T Homogeneous polynomial forms for simultaneous stabilizability of families of linear control systems: a tensor product approach %A Claudio Altafini %X The paper uses the formalism of tensor products in order to deal with the problem of simultaneous\\nstabilizability of a family of linear control systems by means of Lyapunov functions which are homogeneous polynomial forms. While the feedback synthesis seems to be nonconvex, the simultaneous stability by means of homogeneous polynomial forms of the uncontrollable modes yields (convex) necessary but not sufficient conditions for simultaneous stabilizability. %B IEEE Trans. Automat. Control 51 (2006) 1566-1571 %G en_US %U http://hdl.handle.net/1963/2226 %1 2018 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-15T14:17:52Z\\nNo. of bitstreams: 1\\nhompol.pdf: 129083 bytes, checksum: b5ec376b1dc4ee7dde55d731b63ac25c (MD5) %R 10.1109/TAC.2006.880811 %0 Journal Article %J Commun. Math. Phys. 263 (2006) 65-88 %D 2006 %T A Hopf bundle over a quantum four-sphere from the symplectic group %A Giovanni Landi %A Chiara Pagani %A Cesare Reina %X We construct a quantum version of the SU(2) Hopf bundle $S^7 \\\\to S^4$. The quantum sphere $S^7_q$ arises from the symplectic group $Sp_q(2)$ and a quantum 4-sphere $S^4_q$ is obtained via a suitable self-adjoint idempotent $p$ whose entries generate the algebra $A(S^4_q)$ of polynomial functions over it. This projection determines a deformation of an (anti-)instanton bundle over the classical sphere $S^4$. We compute the fundamental $K$-homology class of $S^4_q$ and pair it with the class of $p$ in the $K$-theory getting the value -1 for the topological charge. There is a right coaction of $SU_q(2)$ on $S^7_q$ such that the algebra $A(S^7_q)$ is a non trivial quantum principal bundle over $A(S^4_q)$ with structure quantum group $A(SU_q(2))$. %B Commun. Math. Phys. 263 (2006) 65-88 %G en_US %U http://hdl.handle.net/1963/2179 %1 2065 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-04T12:11:37Z\\nNo. of bitstreams: 1\\n0407342v2.pdf: 282873 bytes, checksum: e4341c8c3cce9ea132fe6c6916a61526 (MD5) %R 10.1007/s00220-005-1494-3 %0 Report %D 2006 %T Infinite Horizon Noncooperative Differential Games %A Alberto Bressan %A Fabio S. Priuli %X For a non-cooperative differential game, the value functions of the various players satisfy a system of Hamilton-Jacobi equations. In the present paper, we consider a class of infinite-horizon games with nonlinear costs exponentially discounted in time. By the analysis of the value\\nfunctions, we establish the existence of Nash equilibrium solutions in feedback form and provide results and counterexamples on their uniqueness and stability. %B J. Differential Equations 227 (2006) 230-257 %G en_US %U http://hdl.handle.net/1963/1720 %1 2431 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-01-24T09:08:57Z\\nNo. of bitstreams: 1\\nmath.AP0505212.pdf: 267217 bytes, checksum: 4c2f5eb11250fa9b31d9b46983c201e0 (MD5) %R 10.1016/j.jde.2006.01.005 %0 Journal Article %J Comm. Pure Appl. Math. 59 (2006) 1604-1638 %D 2006 %T An instability of the Godunov scheme %A Alberto Bressan %A Helge Kristian Jenssen %A Paolo Baiti %X We construct a solution to a $2\\\\times 2$ strictly hyperbolic system of conservation laws, showing that the Godunov scheme \\\\cite{Godunov59} can produce an arbitrarily large amount of oscillations. This happens when the speed of a shock is close to rational, inducing a resonance with the grid. Differently from the Glimm scheme or the vanishing viscosity method, for systems of conservation laws our counterexample indicates that no a priori BV bounds or $L^1$ stability estimates can in general be valid for finite difference schemes. %B Comm. Pure Appl. Math. 59 (2006) 1604-1638 %G en_US %U http://hdl.handle.net/1963/2183 %1 2061 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-05T07:52:50Z\\nNo. of bitstreams: 1\\n0502125v1.pdf: 337578 bytes, checksum: 41193faac363c00e9f80d6c05c0b098c (MD5) %R 10.1002/cpa.20141 %0 Report %D 2006 %T Large Parameter Behavior of Equilibrium Measures %A Tamara Grava %A Fei-Ran Tian %X We study the equilibrium measure for a logarithmic potential in the presence of an external field V*(x) + tp(x), where t is a parameter, V*(x) is a smooth function and p(x) a monic polynomial. When p(x) is of an odd degree, the equilibrium measure is shown to be supported on a single interval as |t| is sufficiently large. When p(x) is of an even degree, the equilibrium measure is supported on two disjoint intervals as t is negatively large; it is supported on a single interval for convex p(x) as t is positively large and is likely to be supported on multiple disjoint intervals for non-convex p(x). %B Commun. Math. Sci. 4 (2006) 551-573 %G en_US %U http://hdl.handle.net/1963/1789 %1 2755 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-30T13:50:45Z\\nNo. of bitstreams: 1\\n92FM-2005.pdf: 291341 bytes, checksum: 132e37e5c4fc64315d52903eed85753f (MD5) %0 Report %D 2006 %T Local Index Formula on the Equatorial Podles Sphere %A Francesco D\'Andrea %A Ludwik Dabrowski %X We discuss spectral properties of the equatorial Podles sphere. As a preparation we also study the `degenerate\\\' (i.e. $q=0$) case (related to the quantum disk). We consider two different spectral triples: one related to the Fock representation of the Toeplitz algebra and the isopectral one.... %B Lett. Math. Phys. 75 (2006) 235-254 %G en_US %U http://hdl.handle.net/1963/1782 %1 2762 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-30T11:54:30Z\\nNo. of bitstreams: 1\\n85FM-2005.pdf: 241084 bytes, checksum: 22ea5eb072a67393221cdb0284ab323d (MD5) %R 10.1007/s11005-005-0047-1 %0 Journal Article %J Journal of Physics A: Mathematical and General, Volume 39, Issue 39, 29 September 2006, Article numberS02, Pages 11973-12031 %D 2006 %T Matching Procedure for the Sixth Painlevé Equation (May 2006) %A Davide Guzzetti %X We present a constructive procedure to obtain the critical behavior of\r\nPainleve\' VI transcendents and solve the connection problem. This procedure\r\nyields two and one parameter families of solutions, including trigonometric and\r\nlogarithmic behaviors, and three classes of solutions with Taylor expansion at\r\na critical point. %B Journal of Physics A: Mathematical and General, Volume 39, Issue 39, 29 September 2006, Article numberS02, Pages 11973-12031 %I SISSA %G en %U http://hdl.handle.net/1963/6524 %1 6474 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Davide Guzzetti (guzzetti@sissa.it) on 2013-03-12T10:58:15Z\nNo. of bitstreams: 1\n1010.1952v1.pdf: 554736 bytes, checksum: 574f14d78ead655022ad9c30ebed720f (MD5) %R doi:10.1088/0305-4470/39/39/S02 %0 Report %D 2006 %T N=1 superpotentials from multi-instanton calculus %A Francesco Fucito %A Jose F. Morales %A Rubik Poghossian %A Alessandro Tanzini %X In this paper we compute gaugino and scalar condensates in N = 1 supersymmetric gauge\\ntheories with and without massive adjoint matter, using localization formulae over the multi-instanton moduli space. Furthermore we compute the chiral ring relations among the correlators of the N = 1* theory and check this result against the multi-instanton computation finding agreement. %B JHEP01(2006)031 %G en_US %U http://hdl.handle.net/1963/1773 %1 2771 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-29T07:58:23Z\\nNo. of bitstreams: 1\\n73FM-2005.pdf: 325303 bytes, checksum: 89f205e907378d543e7a51042f437c8a (MD5) %R 10.1088/1126-6708/2006/01/031 %0 Report %D 2006 %T Normal bundles to Laufer rational curves in local Calabi-Yau threefolds %A Ugo Bruzzo %A Antonio Ricco %X We prove a conjecture by F. Ferrari. Let X be the total space of a nonlinear deformation of a rank 2 holomorphic vector bundle on a smooth rational curve, such that X has trivial canonical bundle and has sections. Then the normal bundle to such sections is computed in terms of the rank of the Hessian of a suitably defined superpotential at its critical points. %B Lett. Math. Phys. 76 (2006) 57-63 %G en_US %U http://hdl.handle.net/1963/1785 %1 2759 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-30T13:06:11Z\\nNo. of bitstreams: 1\\n88FM-2005.pdf: 106989 bytes, checksum: c39c0a1665f5c8185a573959a67e9a72 (MD5) %R 10.1007/s11005-006-0057-7 %0 Journal Article %J Adv. Differential Equations 11 (2006) 931-960 %D 2006 %T On Palais-Smale sequences for H-systems: some examples %A Paolo Caldiroli %A Roberta Musina %X We exhibit a series of examples of Palais-Smale sequences for the Dirichlet problem associated to the mean curvature equation with null boundary condition, and we show that in the case of nonconstant mean curvature functions different kinds of blow up phenomena appear and Palais-Smale sequences may have quite wild behaviour. %B Adv. Differential Equations 11 (2006) 931-960 %G en_US %U http://hdl.handle.net/1963/2157 %1 2087 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-02T07:36:26Z\\nNo. of bitstreams: 1\\n32M.pdf: 296654 bytes, checksum: 7052b4b72f783376708b6bc60c882375 (MD5) %0 Journal Article %J Atti della Accademia Nazionale dei Lincei, Classe di Scienze Fisiche, Matematiche e Naturali, Rendiconti Lincei Matematica e Applicazioni %D 2006 %T Periodic solutions of nonlinear wave equations for asymptotically full measure sets of frequencies %A Baldi, P %A Massimiliano Berti %X We prove existence and multiplicity of small amplitude periodic solutions of completely resonant nonlinear wave equations with Dirichlet boundary conditions for asymptotically full measure sets of frequencies, extending the results of [7] to new types of nonlinearities. %B Atti della Accademia Nazionale dei Lincei, Classe di Scienze Fisiche, Matematiche e Naturali, Rendiconti Lincei Matematica e Applicazioni %V 17 %P 257-277 %G eng %0 Journal Article %J J. Differential Geom. 73 (2006) 1-44 %D 2006 %T Q-curvature flow on S^4 %A Andrea Malchiodi %A Michael Struwe %B J. Differential Geom. 73 (2006) 1-44 %G en_US %U http://hdl.handle.net/1963/2193 %1 2051 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-10T11:52:21Z\\nNo. of bitstreams: 1\\nQ-curv-Nov-05.pdf: 298052 bytes, checksum: 2916315e6ffcef99b7748745e768d831 (MD5) %0 Journal Article %J Czechoslovak Journal of Physics 56 (2006), n. 10-11, 1143-1148 %D 2006 %T Quantisation of bending flows %A Gregorio Falqui %A Fabio Musso %X We briefly review the Kapovich-Millson notion of Bending flows as an integrable system on the space of polygons in ${\\\\bf R}^3$, its connection with a specific Gaudin XXX system, as well as the generalisation to $su(r), r>2$. Then we consider the quantisation problem of the set of Hamiltonians pertaining to the problem, quite naturally called Bending Hamiltonians, and prove that their commutativity is preserved at the quantum level. %B Czechoslovak Journal of Physics 56 (2006), n. 10-11, 1143-1148 %G en_US %U http://hdl.handle.net/1963/2537 %1 1582 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-12-19T10:53:01Z\\nNo. of bitstreams: 1\\n0610003v1.pdf: 113471 bytes, checksum: 34a8a67eda45bff5d2e70aaa0c1edf65 (MD5) %R 10.1007/s10582-006-0415-9 %0 Journal Article %J Comm. Partial Differential Equations 31 (2006) 959 - 985 %D 2006 %T Quasi-periodic solutions of completely resonant forced wave equations %A Massimiliano Berti %A Michela Procesi %X We prove existence of quasi-periodic solutions with two frequencies of completely resonant, periodically forced nonlinear wave equations with periodic spatial boundary conditions. We consider both the cases the forcing frequency is: (Case A) a rational number and (Case B) an irrational number. %B Comm. Partial Differential Equations 31 (2006) 959 - 985 %G en_US %U http://hdl.handle.net/1963/2234 %1 2010 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-16T07:48:45Z\\nNo. of bitstreams: 1\\n0504406v1.pdf: 330239 bytes, checksum: 5dbf59bdd590a6876ea206f70cf0ecc9 (MD5) %R 10.1080/03605300500358129 %0 Journal Article %J Arch. Ration. Mech. Anal. 180 (2006) 237-291 %D 2006 %T Quasistatic evolution problems for linearly elastic-perfectly plastic materials %A Gianni Dal Maso %A Antonio DeSimone %A Maria Giovanna Mora %X The problem of quasistatic evolution in small strain associative elastoplasticity is studied in the framework of the variational theory for rate-independent processes. Existence of solutions is proved through the use of incremental variational problems in spaces of functions with bounded deformation. This provides a new approximation result for the solutions of the quasistatic evolution problem, which are shown to be absolutely continuous in time. Four equivalent formulations of the problem in rate form are derived. A strong formulation of the flow rule is obtained by introducing a precise definition of the stress on the singular set of the plastic strain. %B Arch. Ration. Mech. Anal. 180 (2006) 237-291 %G en_US %U http://hdl.handle.net/1963/2129 %1 2114 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-18T10:14:12Z\\nNo. of bitstreams: 1\\n0412212v1.pdf: 419970 bytes, checksum: fa4e3c2a5db22bfa28aa4f682cb55da4 (MD5) %R 10.1007/s00205-005-0407-0 %0 Journal Article %J Proc. Roy. Soc. Edinburgh Sect. A 136 (2006) 889-907 %D 2006 %T Radial solutions concentrating on spheres of nonlinear Schrödinger equations with vanishing potentials %A Antonio Ambrosetti %A David Ruiz %X We prove the existence of radial solutions of 1.2) concentrating at a sphere for potentials which might be zero and might decay to zero at\\r\\ninfinity. The proofs use a perturbation technique in a variational setting, through a Lyapunov-Schmidt reduction. %B Proc. Roy. Soc. Edinburgh Sect. A 136 (2006) 889-907 %G en_US %U http://hdl.handle.net/1963/1755 %1 2789 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-20T13:11:31Z\\r\\nNo. of bitstreams: 1\\r\\n38M.pdf: 251285 bytes, checksum: e0773652a2fcb13cab0758778b6ea906 (MD5) %R 10.1017/S0308210500004789 %0 Book Section %B The science of hysteresis / eds. Giorgio Bertotti, Isaak D. Mayergoyz. - Amsterdam: Elsevier, 2006. Vol.2, 269-381. %D 2006 %T Recent analytical developments in micromagnetics %A Antonio DeSimone %A Robert V. Kohn %A Stefan Mueller %A Felix Otto %B The science of hysteresis / eds. Giorgio Bertotti, Isaak D. Mayergoyz. - Amsterdam: Elsevier, 2006. Vol.2, 269-381. %@ 978-0-12-480874-4 %G en_US %U http://hdl.handle.net/1963/2230 %1 2014 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-15T15:16:57Z\\nNo. of bitstreams: 1\\nDKMO.pdf: 1644450 bytes, checksum: 4c1079e4854e372d31af9a285f87f400 (MD5) %0 Journal Article %J J. Math. Phys. 47 (2006) 032104 %D 2006 %T Reflection symmetries for multiqubit density operators %A Claudio Altafini %A Timothy F. Havel %X For multiqubit density operators in a suitable tensorial basis, we show that a number of nonunitary operations used in the detection and synthesis of entanglement are classifiable as reflection symmetries, i.e., orientation changing rotations. While one-qubit reflections correspond to antiunitary symmetries, as is known for example from the partial transposition criterion, reflections on the joint density of two or more qubits are not accounted for by the Wigner Theorem and are well-posed only for sufficiently mixed states. One example of such nonlocal reflections is the unconditional NOT operation on a multiparty density, i.e., an operation yelding another density and such that the sum of the two is the identity operator. This nonphysical operation is admissible only for sufficiently mixed states. %B J. Math. Phys. 47 (2006) 032104 %G en_US %U http://hdl.handle.net/1963/2121 %1 2122 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-18T06:51:45Z\\nNo. of bitstreams: 1\\n0405123v2.pdf: 247264 bytes, checksum: c504f911bff46e503941a0298617759a (MD5) %R 10.1063/1.2181827 %0 Journal Article %J Differential Geom. Appl. 24 (2006) 403-416 %D 2006 %T Semistability vs. nefness for (Higgs) vector bundles %A Ugo Bruzzo %A Daniel Hernandez Ruiperez %X According to Miyaoka, a vector bundle E on a smooth projective curve is semistable if and only if a certain numerical class in the projectivized bundle PE is nef. We establish a similar criterion for the semistability of Higgs bundles: namely, such a bundle is semistable if and only if for every integer s between 0 and the rank of E, a suitable numerical class in the scheme parametrizing the rank s locally-free Higgs quotients of E is nef. We also extend this result to higher-dimensional complex projective varieties by showing that the nefness of the above mentioned classes is equivalent to the semistability of the Higgs bundle E together with the vanishing of the discriminant of E. %B Differential Geom. Appl. 24 (2006) 403-416 %G en_US %U http://hdl.handle.net/1963/2237 %1 2007 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-16T09:06:35Z\\nNo. of bitstreams: 1\\n0310040v3.pdf: 216788 bytes, checksum: 574f5aac93686c2348a6313bd129cb61 (MD5) %R 10.1016/j.difgeo.2005.12.007 %0 Report %D 2006 %T On Separation of Variables for Homogeneous SL(r) Gaudin Systems %A Gregorio Falqui %A Fabio Musso %X By means of a recently introduced bihamiltonian structure for the homogeneous Gaudin models, we find a new set of Separation Coordinates for the sl(r) case. %B Math. Phys. Anal. Geom. 9 (2006), n. 3, 233-262 (2007) %G en_US %U http://hdl.handle.net/1963/2538 %1 1581 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-12-19T11:26:08Z\\nNo. of bitstreams: 1\\n0402026v1.pdf: 312976 bytes, checksum: e99c241d72908de5b5bf69b0a7dd1c5c (MD5) %R 10.1007/s11040-006-9012-1 %0 Journal Article %J J. Math. Phys. 47 (2006) 062105 %D 2006 %T Spectral geometry of $\\\\kappa$-Minkowski space %A Francesco D\'Andrea %X After recalling Snyder\\\'s idea of using vector fields over a smooth manifold as `coordinates on a noncommutative space\\\', we discuss a two dimensional toy-model whose `dual\\\' noncommutative coordinates form a Lie algebra: this is the well known $\\\\kappa$-Minkowski space.\\nWe show how to improve Snyder\\\'s idea using the tools of quantum groups and noncommutative geometry. We find a natural representation of the coordinate algebra of $\\\\kappa$-Minkowski as linear operators on an Hilbert space study its `spectral properties\\\' and discuss how to obtain a Dirac operator for this space. We describe two Dirac operators. The first is associated with a spectral triple. We prove that the cyclic integral of M. Dimitrijevic et al. can be obtained as Dixmier trace associated to this triple. The second Dirac operator is equivariant for the action of the quantum Euclidean group, but it has unbounded commutators with the algebra. %B J. Math. Phys. 47 (2006) 062105 %G en_US %U http://hdl.handle.net/1963/2131 %1 2112 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-18T11:48:16Z\\nNo. of bitstreams: 1\\n0503012v4.pdf: 270606 bytes, checksum: b96bcb17609481fbf7d542681a2c0cfa (MD5) %R 10.1063/1.2204808 %0 Report %D 2006 %T Stability of planar nonlinear switched systems %A Ugo Boscain %A Grégoire Charlot %A Mario Sigalotti %X We consider the time-dependent nonlinear system ˙ q(t) = u(t)X(q(t)) + (1 − u(t))Y (q(t)), where q ∈ R2, X and Y are two smooth vector fields, globally asymptotically stable at the origin and u : [0,∞) → {0, 1} is an arbitrary measurable function. Analysing the topology of the set where X and Y are parallel, we give some sufficient and some necessary conditions for global asymptotic stability, uniform with respect to u(.). Such conditions can be verified without any integration or construction of a Lyapunov function, and they are robust under small perturbations of the vector fields. %B Discrete Contin. Dyn. Syst. 15 (2006) 415-432 %G en_US %U http://hdl.handle.net/1963/1710 %1 2441 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-01-18T08:35:31Z\\nNo. of bitstreams: 1\\nmath.OC0502361.pdf: 322404 bytes, checksum: e56f0d709d97e2e300e3cb9d4a629a1b (MD5) %0 Journal Article %J Lett. Math. Phys. 76 (2006) 187-214 %D 2006 %T Thomae type formulae for singular Z_N curves %A Victor Z. Enolski %A Tamara Grava %X We give an elementary and rigorous proof of the Thomae type formula for singular $Z_N$ curves. To derive the Thomae formula we use the traditional variational method which goes back to Riemann, Thomae and Fuchs. An important step of the proof is the use of the Szego kernel computed explicitly in algebraic form for non-singular 1/N-periods. The proof inherits principal points of Nakayashiki\\\'s proof [31], obtained for non-singular ZN curves. %B Lett. Math. Phys. 76 (2006) 187-214 %G en_US %U http://hdl.handle.net/1963/2125 %1 2118 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-09-18T08:04:36Z\\nNo. of bitstreams: 1\\n0602017v1.pdf: 315977 bytes, checksum: 2f5c46aa04d9dd6c02200ff627d69a00 (MD5) %R 10.1007/s11005-006-0073-7 %0 Report %D 2006 %T Time Minimal Trajectories for a Spin 1/2 Particle in a Magnetic field %A Ugo Boscain %A Paolo Mason %X In this paper we consider the minimum time population transfer problem for the z-component\\nof the spin of a (spin 1/2) particle driven by a magnetic field, controlled along the x axis, with bounded amplitude. On the Bloch sphere (i.e. after a suitable Hopf projection), this problem can be attacked with techniques of optimal syntheses on 2-D manifolds. Let (-E,E) be the two energy levels, and |omega (t)| ≤ M the bound on the field amplitude. For each couple of values E and M, we determine the time optimal synthesis starting from the level -E and we provide the explicit expression of the time optimal trajectories steering the state one to the state two, in terms of a parameter that can be computed solving numerically a suitable equation. For M/E << 1, every time optimal trajectory is bang-bang and in particular the corresponding control is periodic with frequency of the order of the resonance frequency wR = 2E. On the other side, for M/E > 1, the time optimal trajectory steering the state one to the state two is bang-bang with exactly one switching. Fixed E we also prove that for M → ∞ the time needed to reach the state two tends to zero. In the case M/E > 1 there are time optimal trajectories containing a singular arc. Finally we compare these results with some known results of Khaneja, Brockett and Glaser and with those obtained by controlling the magnetic field both on the x and y directions (or with one external field, but in the rotating wave approximation). As byproduct we prove that the qualitative shape of the time optimal synthesis presents different patterns, that cyclically alternate as M/E → 0, giving a partial proof of a conjecture formulated in a previous paper. %B Journal of Mathematical Physics 47, 062101 (2006) %G en_US %U http://hdl.handle.net/1963/1734 %1 2418 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-02-03T08:14:36Z\\nNo. of bitstreams: 1\\nquant-ph0512074.pdf: 550597 bytes, checksum: 588a3483219fa1360d5f71c131e2488e (MD5) %R 10.1063/1.2203236 %0 Report %D 2006 %T On topological M-theory %A Giulio Bonelli %A Alessandro Tanzini %A Maxim Zabzine %X We construct a gauge fixed action for topological membranes on G2-manifolds such that its bosonic part is the standard membrane theory in a particular gauge. We prove that quantum mechanically the path-integral in this gauge localizes on associative submanifolds. %B Adv. Theor. Math. Phys. 10 (2006) 239-260 %G en_US %U http://hdl.handle.net/1963/1765 %1 2779 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-23T14:41:22Z\\nNo. of bitstreams: 1\\n64FM.pdf: 240192 bytes, checksum: 3c2a8717b7a8a0d235cc7a6ef9e76369 (MD5) %0 Journal Article %J J. Geom. Phys. 56 (2006) 2379-2401 %D 2006 %T Topological symmetry of forms, N=1 supersymmetry and S-duality on special manifolds %A Laurent Baulieu %A Alessandro Tanzini %X We study the quantization of a holomorphic two-form coupled to a Yang-Mills field on special manifolds in various dimensions, and we show that it yields twisted supersymmetric theories. The construction determines ATQFT\\\'s (Almost Topological Quantum Field Theories), that is, theories with observables that are invariant under changes of metrics belonging to restricted classes. For Kahler manifolds in four dimensions, our topological model is related to N=1 Super Yang-Mills theory. Extended supersymmetries are recovered by considering the coupling with chiral multiplets. We also analyse Calabi-Yau manifolds in six and eight dimensions, and seven dimensional G_2 manifolds of the kind recently discussed by Hitchin. We argue that the two-form field could play an interesting role for the study of the conjectured S-duality in topological string. We finally show that in the case of real forms in six dimensions the partition function of our topological model is related to the square of that of the holomorphic Chern-Simons theory, and we discuss the uplift to seven dimensions and its relation with the recent proposals for the topological M-theory. %B J. Geom. Phys. 56 (2006) 2379-2401 %G en_US %U http://hdl.handle.net/1963/2168 %1 2076 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-03T07:58:25Z\\nNo. of bitstreams: 1\\n0412014v2.pdf: 317935 bytes, checksum: a9478cff2fa4dc504efece63810fb6ed (MD5) %R 10.1016/j.geomphys.2005.12.006 %0 Book Section %B Geometry, topology, and mathematical physics : S.P. Novikov\\\'s seminar : 2006-2007 / V.M. Buchstaber, I.M. Krichever, editors. - Providence, R.I. : American Mathematical Society, 2008. - pages : 59-109 %D 2006 %T On universality of critical behaviour in Hamiltonian PDEs %A Boris Dubrovin %X Our main goal is the comparative study of singularities of solutions to\\r\\nthe systems of rst order quasilinear PDEs and their perturbations containing higher\\r\\nderivatives. The study is focused on the subclass of Hamiltonian PDEs with one\\r\\nspatial dimension. For the systems of order one or two we describe the local structure\\r\\nof singularities of a generic solution to the unperturbed system near the point of\\r\\n\\\\gradient catastrophe\\\" in terms of standard objects of the classical singularity theory;\\r\\nwe argue that their perturbed companions must be given by certain special solutions\\r\\nof Painlev e equations and their generalizations. %B Geometry, topology, and mathematical physics : S.P. Novikov\\\'s seminar : 2006-2007 / V.M. Buchstaber, I.M. Krichever, editors. - Providence, R.I. : American Mathematical Society, 2008. - pages : 59-109 %I American Mathematical Society %@ 978-0-8218-4674-2 %G en %U http://hdl.handle.net/1963/6491 %1 6417 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Boris Dubrovin (dubrovin@sissa.it) on 2013-02-11T14:49:10Z\\nNo. of bitstreams: 1\\ndubrovin_2008_ams.pdf: 671674 bytes, checksum: 08be98e78f30199030c7a4062cfcb8cf (MD5) %0 Journal Article %J Differential Geom. Appl. 24 (2006) 235-259 %D 2006 %T On variational approach to differential invariants of rank two distributions %A Igor Zelenko %X n the present paper we construct differential invariants for generic rank 2 vector distributions on n-dimensional manifold. In the case n=5 (the first case containing functional parameters) E. Cartan found in 1910 the covariant fourth-order tensor invariant for such distributions, using his \\\"reduction-prolongation\\\" procedure. After Cartan\\\'s work the following questions remained open: first the geometric reason for existence of Cartan\\\'s tensor was not clear; secondly it was not clear how to generalize this tensor to other classes of distributions; finally there were no explicit formulas for computation of Cartan\\\'s tensor. Our paper is the first in the series of papers, where we develop an alternative approach, which gives the answers to the questions mentioned above. It is based on the investigation of dynamics of the field of so-called abnormal extremals (singular curves) of rank 2 distribution and on the general theory of unparametrized curves in the Lagrange Grassmannian, developed in our previous works with A. Agrachev . In this way we construct the fundamental form and the projective Ricci curvature of rank 2 vector distributions for arbitrary n greater than 4.\\nFor n=5 we give an explicit method for computation of these invariants and demonstrate it on several examples. In our next paper we show that in the case n=5 our fundamental form coincides with Cartan\\\'s tensor. %B Differential Geom. Appl. 24 (2006) 235-259 %G en_US %U http://hdl.handle.net/1963/2188 %1 2056 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-05T11:38:23Z\\nNo. of bitstreams: 1\\n0402171v2.pdf: 447361 bytes, checksum: e7f578202115704506587340079a39d3 (MD5) %R 10.1016/j.difgeo.2005.09.004 %0 Report %D 2006 %T Variational problems in fracture mechanics %A Gianni Dal Maso %X We present some recent existence results for the variational model of crack growth in brittle materials proposed by Francfort and Marigo in 1998. These results, obtained in collaboration with Francfort and Toader, cover the case of arbitrary space dimension with a general quasiconvex bulk energy and with prescribed boundary deformations and applied loads. %G en_US %U http://hdl.handle.net/1963/1816 %1 2398 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-04-18T12:50:25Z\\nNo. of bitstreams: 1\\nmath.AP0602614.pdf: 122115 bytes, checksum: 8a582db939c08c52510bcc1c7da7c563 (MD5) %0 Book Section %B Encyclopedia of Mathematical Physics. Vol 1 A : A-C. Oxford: Elsevier, 2006, p. 438-447 %D 2006 %T WDVV equations and Frobenius manifolds %A Boris Dubrovin %B Encyclopedia of Mathematical Physics. Vol 1 A : A-C. Oxford: Elsevier, 2006, p. 438-447 %I SISSA %@ 0125126611 %G en %U http://hdl.handle.net/1963/6473 %1 6419 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Boris Dubrovin (dubrovin@sissa.it) on 2013-02-11T14:55:56Z\\nNo. of bitstreams: 1\\ndubrovin_2006_enc.pdf: 16392102 bytes, checksum: 90fed38af94f1692c7c4375ca8bf30c3 (MD5) %0 Journal Article %J Comm. Anal. Geom. 13 (2005) 187-252 %D 2005 %T Asymptotic Morse theory for the equation $\\\\Delta v=2v\\\\sb x\\\\wedge v\\\\sb y$ %A Sagun Chanillo %A Andrea Malchiodi %X Given a smooth bounded domain ${\\\\O}\\\\subseteq \\\\R^2$, we consider the equation $\\\\D v = 2 v_x \\\\wedge v_y$ in $\\\\O$, where $v: {\\\\O}\\\\to \\\\R^3$. We prescribe Dirichlet boundary datum, and consider the case in which this datum converges to zero. An asymptotic study of the corresponding Euler functional is performed, analyzing multiple-bubbling phenomena. This allows us to settle a particular case of a question raised by H. Brezis and J.M. Coron. %B Comm. Anal. Geom. 13 (2005) 187-252 %I International Press %G en_US %U http://hdl.handle.net/1963/3533 %1 731 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-02-20T10:28:24Z\\nNo. of bitstreams: 1\\n0205106v1.pdf: 508637 bytes, checksum: 9894eb1ef04ac61cd02aebdee04ff5fa (MD5) %0 Journal Article %J SIAM J. Control Optim. 43 (2005) 2166-2190 %D 2005 %T On the attainable set for Temple class systems with boundary controls %A Fabio Ancona %A Giuseppe Maria Coclite %X Consider the initial-boundary value problem for a strictly hyperbolic, genuinely nonlinear, Temple class system of conservation laws % $$ u_t+f(u)_x=0, \\\\qquad u(0,x)=\\\\ov u(x), \\\\qquad {{array}{ll} &u(t,a)=\\\\widetilde u_a(t), \\\\noalign{\\\\smallskip} &u(t,b)=\\\\widetilde u_b(t), {array}. \\\\eqno(1) $$ on the domain $\\\\Omega =\\\\{(t,x)\\\\in\\\\R^2 : t\\\\geq 0, a \\\\le x\\\\leq b\\\\}.$ We study the mixed problem (1) from the point of view of control theory, taking the initial data $\\\\bar u$ fixed, and regarding the boundary data $\\\\widetilde u_a, \\\\widetilde u_b$ as control functions that vary in prescribed sets $\\\\U_a, \\\\U_b$, of $\\\\li$ boundary controls. In particular, we consider the family of configurations $$ \\\\A(T) \\\\doteq \\\\big\\\\{u(T,\\\\cdot); ~ u {\\\\rm is a sol. to} (1), \\\\quad \\\\widetilde u_a\\\\in \\\\U_a, \\\\widetilde u_b \\\\in \\\\U_b \\\\big\\\\} $$ that can be attained by the system at a given time $T>0$, and we give a description of the attainable set $\\\\A(T)$ in terms of suitable Oleinik-type conditions. We also establish closure and compactness of the set $\\\\A(T)$ in the $lu$ topology. %B SIAM J. Control Optim. 43 (2005) 2166-2190 %I SISSA Library %G en %U http://hdl.handle.net/1963/1581 %1 2537 %2 Mathematics %3 Functional Analysis and Applications %$ Made available in DSpace on 2004-09-01T13:04:51Z (GMT). No. of bitstreams: 1\\nmath.AP0205167.pdf: 356214 bytes, checksum: 05474bd7744107031887816262b561b3 (MD5)\\n Previous issue date: 2002 %R 10.1137/S0363012902407776 %0 Journal Article %J Discrete Contin. Dyn. Syst. 13 (2005) 1-12 %D 2005 %T On the Blow-up for a Discrete Boltzmann Equation in the Plane %A Alberto Bressan %A Massimo Fonte %X We study the possibility of finite-time blow-up for a two dimensional Broadwell model. In a set of rescaled variables, we prove that no self-similar blow-up solution exists, and derive some a priori bounds on the blow-up rate. In the final section, a possible blow-up scenario is discussed. %B Discrete Contin. Dyn. Syst. 13 (2005) 1-12 %G en_US %U http://hdl.handle.net/1963/2244 %1 2000 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-17T09:31:05Z\\nNo. of bitstreams: 1\\n0403047v2.pdf: 116770 bytes, checksum: a7432c5b660f4e4672c952003dd0210f (MD5) %0 Journal Article %J Phys. Rev. A 72 (2005) 012112 %D 2005 %T Commuting multiparty quantum observables and local compatibility %A Claudio Altafini %X A formula for the commutator of tensor product matrices is used to shows that, for qubits, compatibility of quantum multiparty observables almost never implies local compatibility at each site and to predict when this happens/does not happen in a concise manner. In particular, it is shown that two ``fully nontrivial\\\'\\\' $n$-qubit observables are compatible locally and globally if and only if they are equal up to sign. In addition, the formula gives insight into the construction of new paradoxes of the type of the Kochen-Specker Theorem, which can then be easily rephrased into proposals for new no hidden variable experiments of the type of the ``Bell Theorem without inequalities\\\'\\\'. %B Phys. Rev. A 72 (2005) 012112 %G en_US %U http://hdl.handle.net/1963/2228 %1 2016 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-15T14:36:34Z\\nNo. of bitstreams: 1\\nqu-ent-comm.pdf: 168766 bytes, checksum: 05858df702df633ee1fa71d76f76d1b4 (MD5) %R 10.1103/PhysRevA.72.012112 %0 Book Section %B Differential geometry and its applications, 367-382, Matfyzpress, Prague, 2005 %D 2005 %T Complete systems of invariants for rank 1 curves in Lagrange Grassmannians %A Igor Zelenko %X Curves in Lagrange Grassmannians naturally appear when one studies intrinsically \\\"the Jacobi equations for extremals\\\", associated with control systems and geometric structures. In this way one reduces the problem of construction of the curvature-type invariants for these objects to the much more concrete problem of finding of invariants of curves in Lagrange Grassmannians w.r.t. the action of the linear Symplectic group. In the present paper we develop a new approach to differential geometry of so-called rank 1 curves in Lagrange Grassmannian, i.e., the curves with velocities being rank one linear mappings (under the standard identification of the tangent space to a point of the Lagrange Grassmannian with an appropriate space of linear mappings). The curves of this class are associated with \\\"the Jacobi equations for extremals\\\", corresponding to control systems with scalar control and to rank 2 vector distributions. In particular, we construct the tuple of m principal invariants, where m is equal to half of dimension of the ambient linear symplectic space, such that for a given tuple of arbitrary m smooth functions there exists the unique, up to a symplectic transformation, rank 1 curve having this tuple, as the tuple of the principal invariants. This approach extends and essentially simplifies some results of our previous paper (J. Dynamical and Control Systems, 8, 2002, No. 1, 93-140), where only the uniqueness part was proved and in rather cumbersome way. It is based on the construction of the new canonical moving frame with the most simple structural equation. %B Differential geometry and its applications, 367-382, Matfyzpress, Prague, 2005 %G en_US %U http://hdl.handle.net/1963/2310 %1 1706 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-29T14:39:11Z\\nNo. of bitstreams: 1\\n0411190v1.pdf: 227302 bytes, checksum: f4c17631a146df10f7ea9facaa0949b2 (MD5) %0 Journal Article %J Geometric and Functional Analysis 15 (6) 1162-1222 (2005) %D 2005 %T Concentration at curves for a singularly perturbed Neumann problem in three-dimensional domains %A Andrea Malchiodi %X We prove new concentration phenomena for the equation −ɛ2 Δu + u = up in a smooth bounded domain R3 and with Neumann boundary conditions. Here p > 1 and ɛ > 0 is small. We show that concentration of solutions occurs at some geodesics of ∂Ω when ɛ → 0. %B Geometric and Functional Analysis 15 (6) 1162-1222 (2005) %I Springer %G en %U http://hdl.handle.net/1963/4866 %1 4645 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-20T13:51:52Z\\nNo. of bitstreams: 1\\nMalchiodi03.pdf: 521628 bytes, checksum: 3aa8a237bad84b04bdd17669f210e057 (MD5) %R 10.1007/s00039-005-0542-7 %0 Journal Article %J SIAM J. Math. Anal. 36 (2005) 1293-1309 %D 2005 %T Conservation laws with time dependent discontinuous coefficients %A Giuseppe Maria Coclite %A Nils Henrik Risebro %X We consider scalar conservation laws where the flux function depends discontinuously on both the spatial and temporal location. Our main results are the existence and well-posedness of an entropy solution to the Cauchy problem. The existence is established by showing that a sequence of front tracking approximations is compact in L1, and that the limits are entropy solutions. Then, using the definition of an entropy solution taken form [11], we show that the solution operator is L1 contractive. These results generalize the corresponding results from [16] and [11]. %B SIAM J. Math. Anal. 36 (2005) 1293-1309 %I SISSA Library %G en %U http://hdl.handle.net/1963/1666 %1 2452 %2 Mathematics %3 Functional Analysis and Applications %$ Made available in DSpace on 2004-09-01T13:06:09Z (GMT). No. of bitstreams: 1\\n96_02.pdf: 3363466 bytes, checksum: 5ed39a522bb68737585e74668afafc5a (MD5)\\n Previous issue date: 2002 %R 10.1137/S0036141002420005 %0 Journal Article %J J. Dyn. Control Syst. 11 (2005) 297-327 %D 2005 %T On curvatures and focal points of distributions of dynamical Lagrangian distributions and their reductions by first integrals %A Andrei Agrachev %A Natalia N. Chtcherbakova %A Igor Zelenko %X Pairs (Hamiltonian system, Lagrangian distribution), called dynamical Lagrangian distributions, appear naturally in Differential Geometry, Calculus of Variations and Rational Mechanics. The basic differential invariants of a dynamical Lagrangian distribution w.r.t. the action of the group of symplectomorphisms of the ambient symplectic manifold are the curvature operator and the curvature form. These invariants can be seen as generalizations of the classical curvature tensor in Riemannian Geometry. In particular, in terms of these invariants one can localize the focal points along extremals of the corresponding variational problems. In the present paper we study the behavior of the curvature operator, the curvature form and the focal points of a dynamical Lagrangian distribution after its reduction by arbitrary first integrals in involution. The interesting phenomenon is that the curvature form of so-called monotone increasing Lagrangian dynamical distributions, which appear naturally in mechanical systems, does not decrease after reduction. It also turns out that the set of focal points to the given point w.r.t. the monotone increasing dynamical Lagrangian distribution and the corresponding set of focal points w.r.t. its reduction by one integral are alternating sets on the corresponding integral curve of the Hamiltonian system of the considered dynamical distributions. Moreover, the first focal point corresponding to the reduced Lagrangian distribution comes before any focal point related to the original dynamical distribution. We illustrate our results on the classical $N$-body problem. %B J. Dyn. Control Syst. 11 (2005) 297-327 %G en_US %U http://hdl.handle.net/1963/2254 %1 1993 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-18T08:53:27Z\\nNo. of bitstreams: 1\\n0409152v1.pdf: 335893 bytes, checksum: bf4dfeb39ad05ff60c2c2cc745fa0fc1 (MD5) %R 10.1007/s10883-005-6581-4 %0 Journal Article %J J. Phys. A 38 (2005) 4769-4781 %D 2005 %T Decay of a bound state under a time-periodic perturbation: a toy case %A Michele Correggi %A Gianfausto Dell'Antonio %X We study the time evolution of a three dimensional quantum particle, initially in a bound state, under the action of a time-periodic zero range interaction with ``strength\\\'\\\' (\\\\alpha(t)). Under very weak generic conditions on the Fourier coefficients of (\\\\alpha(t)), we prove complete ionization as (t \\\\to \\\\infty). We prove also that, under the same conditions, all the states of the system are scattering states. %B J. Phys. A 38 (2005) 4769-4781 %G en_US %U http://hdl.handle.net/1963/2298 %1 1718 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-25T08:22:58Z\\nNo. of bitstreams: 1\\n0408003v2.pdf: 207599 bytes, checksum: 256b29c96ea071184e9455fd1dd92717 (MD5) %R 10.1088/0305-4470/38/22/002 %0 Journal Article %J Commun. Math. Phys. 259 (2005) 729-759 %D 2005 %T The Dirac operator on SU_q(2) %A Ludwik Dabrowski %A Giovanni Landi %A Andrzej Sitarz %A Walter Daniël Van Suijlekom %A Joseph C. Varilly %X We construct a 3^+ summable spectral triple (A(SU_q(2)),H,D) over the quantum group SU_q(2) which is equivariant with respect to a left and a right action of U_q(su(2)). The geometry is isospectral to the classical case since the spectrum of the operator D is the same as that of the usual Dirac operator on the 3-dimensional round sphere. The presence of an equivariant real structure J demands a modification in the axiomatic framework of spectral geometry, whereby the commutant and first-order properties need be satisfied only modulo infinitesimals of arbitrary high order. %B Commun. Math. Phys. 259 (2005) 729-759 %I Springer %G en %U http://hdl.handle.net/1963/4425 %1 4175 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-04T08:01:47Z No. of bitstreams: 1 math_0411609v2.pdf: 293099 bytes, checksum: cfa2846ded2ecf161e83f4269b65e9b2 (MD5) %R 10.1007/s00220-005-1383-9 %0 Journal Article %J Systems and Control Letters, 54 (11):1121-1130, 2005 %D 2005 %T Explicit Wei–Norman formulae for matrix Lie groups via Putzer\\\'s method %A Claudio Altafini %X The Wei–Norman formula locally relates the Magnus solution of a system of linear time-varying ODEs with the solution expressed in terms of products of exponentials by means of a set of nonlinear differential equations in the parameters of the two types of solutions. A closed form expression of such formula is proposed based on the use of Putzer\\\'s method. %B Systems and Control Letters, 54 (11):1121-1130, 2005 %I Elsevier %G en %U http://hdl.handle.net/1963/4538 %1 4299 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-06T12:04:23Z\\nNo. of bitstreams: 1\\nwei-norman.pdf: 201660 bytes, checksum: 6081c4fd935c318f831c791518f8b9c9 (MD5) %R 10.1016/j.sysconle.2005.03.006 %0 Journal Article %J C. R. Acad. Sci. Paris, Ser. I 340 (2005) 341-346. %D 2005 %T A fourth order uniformization theorem on some four manifolds with large total Q-curvature %A Zindine Djadli %A Andrea Malchiodi %X Given a four-dimensional manifold (M,g), we study the existence of a conformal metric for which the Q-curvature, associated to a conformally invariant fourth-order operator (the Paneitz operator), is constant. Using a topological argument, we obtain a new result in cases which were still open. %B C. R. Acad. Sci. Paris, Ser. I 340 (2005) 341-346. %I Elsevier %G en %U http://hdl.handle.net/1963/4868 %1 4649 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-20T14:43:43Z\\nNo. of bitstreams: 1\\nexistencep81.pdf: 151457 bytes, checksum: 024bd42cba2f35fe4c206a1ef0f9a125 (MD5) %R 10.1016/j.crma.2005.01.013 %0 Report %D 2005 %T Gel\\\'fand-Zakharevich Systems and Algebraic Integrability: the Volterra Lattice Revisited %A Gregorio Falqui %A Marco Pedroni %X In this paper we will discuss some features of the bi-Hamiltonian method for solving the Hamilton-Jacobi (H-J) equations by Separation of Variables, and make contact with the theory of Algebraic Complete Integrability and, specifically, with the Veselov-Novikov notion of algebro-geometric (AG) Poisson brackets. %B Regul. Chaotic Dyn. 10 (2005) 399-412 %G en_US %U http://hdl.handle.net/1963/1689 %1 2444 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2005-06-20T13:56:39Z\\nNo. of bitstreams: 1\\nnlin.SI0505018.pdf: 230177 bytes, checksum: 9f91c8fd8d698b1a0a0ad018661f1d34 (MD5) %R 10.1070/RD2005v010n04ABEH000322 %0 Journal Article %J SIAM J. Math. Anal. 37 (2005) 996-1026 %D 2005 %T Global solutions of the Hunter-Saxton equation %A Alberto Bressan %A Adrian Constantin %X We construct a continuous semigroup of weak, dissipative solutions to a nonlinear partial differential equations modeling nematic liquid crystals. A new distance functional, determined by a problem of optimal transportation, yields sharp estimates on the continuity of solutions with respect to the initial data. %B SIAM J. Math. Anal. 37 (2005) 996-1026 %G en_US %U http://hdl.handle.net/1963/2256 %1 1991 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-18T10:16:52Z\\nNo. of bitstreams: 1\\n0502059v1.pdf: 276204 bytes, checksum: ba0bfd37b8aa3a5ef2c0ef7358081cf9 (MD5) %R 10.1137/050623036 %0 Journal Article %J J. Eur. Math. Soc. 7 (2005) 117-144 %D 2005 %T Ground states of nonlinear Schroedinger equations with potentials vanishing at infinity %A Antonio Ambrosetti %A Veronica Felli %A Andrea Malchiodi %X We deal with a class on nonlinear Schr\\\\\\\"odinger equations \\\\eqref{eq:1} with potentials $V(x)\\\\sim |x|^{-\\\\a}$, $0<\\\\a<2$, and $K(x)\\\\sim |x|^{-\\\\b}$, $\\\\b>0$. Working in weighted Sobolev spaces, the existence of ground states $v_{\\\\e}$ belonging to $W^{1,2}(\\\\Rn)$ is proved under the assumption that $p$ satisfies \\\\eqref{eq:p}. Furthermore, it is shown that $v_{\\\\e}$ are {\\\\em spikes} concentrating at a minimum of ${\\\\cal A}=V^{\\\\theta}K^{-2/(p-1)}$, where $\\\\theta= (p+1)/(p-1)-1/2$. %B J. Eur. Math. Soc. 7 (2005) 117-144 %G en_US %U http://hdl.handle.net/1963/2352 %1 1664 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-11-07T08:16:53Z\\nNo. of bitstreams: 1\\nGround states.pdf: 901500 bytes, checksum: 741c3d55677b872a40e8e3ff2df2a5d2 (MD5) %0 Journal Article %J SIAM J. Control Optim. 43 (2005) 1867-1887 %D 2005 %T Hybrid necessary principle %A Mauro Garavello %A Benedetto Piccoli %X We consider a hybrid control system and general optimal control problems for this system. We suppose that the switching strategy imposes restrictions on control sets and we provide necessary conditions for an optimal hybrid trajectory, stating a hybrid necessary principle (HNP). Our result generalizes various necessary principles available in the literature. %B SIAM J. Control Optim. 43 (2005) 1867-1887 %I SIAM %G en %U http://hdl.handle.net/1963/1641 %1 2477 %2 Mathematics %3 Functional Analysis and Applications %$ Made available in DSpace on 2004-09-01T13:05:44Z (GMT). No. of bitstreams: 0\\n Previous issue date: 2002 %R 10.1137/S0363012903416219 %0 Journal Article %J Comm. Math. Phys. 257 (2005) 169-192 %D 2005 %T Ionization for Three Dimensional Time-dependent Point Interactions %A Michele Correggi %A Gianfausto Dell'Antonio %A Rodolfo Figari %A Andrea Mantile %X We study the time evolution of a three dimensional quantum particle under the action of a time-dependent point interaction fixed at the origin. We assume that the ``strength\\\'\\\' of the interaction (\\\\alpha(t)) is a periodic function with an arbitrary mean. Under very weak conditions on the Fourier coefficients of (\\\\alpha(t)), we prove that there is complete ionization as (t \\\\to \\\\infty), starting from a bound state at time (t = 0). Moreover we prove also that, under the same conditions, all the states of the system are scattering states. %B Comm. Math. Phys. 257 (2005) 169-192 %G en_US %U http://hdl.handle.net/1963/2297 %1 1719 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-25T08:14:45Z\\nNo. of bitstreams: 1\\n0402011v2.pdf: 306766 bytes, checksum: 7efb2bcceb4c2699d662ae1af9e7dd76 (MD5) %R 10.1007/s00220-005-1293-x %0 Journal Article %J K-Theory 35 (2005) 375-394 %D 2005 %T The local index formula for SUq(2) %A Walter van Suijlekom %A Ludwik Dabrowski %A Giovanni Landi %A Andrzej Sitarz %A Joseph C. Varilly %X We discuss the local index formula of Connes-Moscovici for the isospectral noncommutative geometry that we have recently constructed on quantum SU(2). We work out the cosphere bundle and the dimension spectrum as well as the local cyclic cocycles yielding the index formula. %B K-Theory 35 (2005) 375-394 %G en_US %U http://hdl.handle.net/1963/1713 %1 2438 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-01-18T10:14:50Z\\nNo. of bitstreams: 1\\nmath.QA0501287.pdf: 189281 bytes, checksum: 75a780cbe958f6093e340102ad9bf176 (MD5) %R 10.1007/s10977-005-3116-4 %0 Journal Article %J Annali della Scuola Normale Superiore di Pisa, Classe di Scienze (5), 4 (2005) 129-177. %D 2005 %T Minimal surfaces in pseudohermitian geometry %A Jih-Hsin Cheng %A JennFang Hwang %A Andrea Malchiodi %A Paul Yang %X We consider surfaces immersed in three-dimensional pseudohermitian manifolds. We define the notion of (p-)mean curvature and of the associated (p-)minimal surfaces, extending some concepts previously given for the (flat) Heisenberg group. We interpret the p-mean curvature not only as the tangential sublaplacian of a defining function, but also as the curvature of a characteristic curve, and as a quantity in terms of calibration geometry. As a differential equation, the p-minimal surface equation is degenerate (hyperbolic and elliptic). To analyze the singular set, we formulate some {\em extension} theorems, which describe how the characteristic curves meet the singular set. This allows us to classify the entire solutions to this equation and to solve a Bernstein-type problem (for graphs over the $xy$-plane) in the Heisenberg group $H_1$. In $H_{1}$, identified with the Euclidean space $R^{3}$, the p-minimal surfaces are classical ruled surfaces with the rulings generated by Legendrian lines. We also prove a uniqueness theorem for the Dirichlet problem under a condition on the size of the singular set in two dimensions, and generalize to higher dimensions without any size control condition. We also show that there are no closed, connected, $C^{2}$ smoothly immersed constant p-mean curvature or p-minimal surfaces of genus greater than one in the standard $S^{3}.$ This fact continues to hold when $S^{3}$ is replaced by a general spherical pseudohermitian 3-manifold. %B Annali della Scuola Normale Superiore di Pisa, Classe di Scienze (5), 4 (2005) 129-177. %I Scuola Normale Superiore %G en %U http://hdl.handle.net/1963/4579 %1 4347 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-07T09:39:45Z No. of bitstreams: 1 math_0401136v3.pdf: 476553 bytes, checksum: 85c9b54a1f7e6c159e8fbc2486849a53 (MD5) %R 10.2422/2036-2145.2005.1.05 %0 Journal Article %J SIAM J. Math. Anal. 37 (2005) 982-995 %D 2005 %T On the Minimum Problem for Nonconvex Scalar Functionals %A Sandro Zagatti %X We study the minimum problem for scalar nonconvex functionals defined on Sobolev maps satisfying a Dirichlet boundary condition and refine well-known existence results under standard regularity assumptions. %B SIAM J. Math. Anal. 37 (2005) 982-995 %G en_US %U http://hdl.handle.net/1963/2764 %1 1936 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-08-29T11:16:58Z\\nNo. of bitstreams: 1\\ngrad3.pdf: 146157 bytes, checksum: 596c11c76c56b834876568a2157e2202 (MD5) %R 10.1137/040612506 %0 Journal Article %J Ann. Inst. Fourier (Grenoble) 55 (2005) 1803-1834 %D 2005 %T Modulation of the Camassa-Holm equation and reciprocal transformations %A Simonetta Abenda %A Tamara Grava %X We derive the modulation equations or Whitham equations for the Camassa-Holm (CH) equation. We show that the modulation equations are hyperbolic and admit bi-Hamiltonian structure. Furthermore they are connected by a reciprocal transformation to the modulation equations of the first negative flow of the Korteweg de Vries (KdV) equation. The reciprocal transformation is generated by the Casimir of the second Poisson bracket of the KdV averaged flow. We show that the geometry of the bi-Hamiltonian structure of the KdV and CH modulation equations is quite different: indeed the KdV averaged bi-Hamiltonian structure can always be related to a semisimple Frobenius manifold while the CH one cannot. %B Ann. Inst. Fourier (Grenoble) 55 (2005) 1803-1834 %G en_US %U http://hdl.handle.net/1963/2305 %1 1711 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-29T10:50:29Z\\nNo. of bitstreams: 1\\n0506042v2.pdf: 305542 bytes, checksum: 045f6c919e0338003f17f6827528ad0d (MD5) %0 Journal Article %J Ann. Inst. H. Poincare Anal. Non Lineaire 22 (2005) 143-163 %D 2005 %T Multiple clustered layer solutions for semilinear Neumann problems on a ball %A Andrea Malchiodi %A Wei-Ming Ni %A Juncheng Wei %B Ann. Inst. H. Poincare Anal. Non Lineaire 22 (2005) 143-163 %I Elsevier %G en_US %U http://hdl.handle.net/1963/3532 %1 732 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-02-20T10:15:49Z\\nNo. of bitstreams: 1\\nMalchiodiNiWei04.pdf: 340366 bytes, checksum: a0bb6df9ca59c557fdacb5e7142ecf3d (MD5) %R 10.1016/j.anihpc.2004.05.003 %0 Journal Article %J Discrete Contin. Dyn. Syst. Ser. B 5 (2005) 957-990 %D 2005 %T Nonisotropic 3-level quantum systems: complete solutions for minimum time and minimum energy %A Ugo Boscain %A Thomas Chambrion %A Grégoire Charlot %X We apply techniques of subriemannian geometry on Lie groups and of optimal synthesis on 2-D manifolds to the population transfer problem in a three-level quantum system driven by two laser pulses, of arbitrary shape and frequency. In the rotating wave approximation, we consider a nonisotropic model i.e. a model in which the two coupling constants of the lasers are different. The aim is to induce transitions from the first to the third level, minimizing 1) the time of the transition (with bounded laser amplitudes),\\n2) the energy of lasers (with fixed final time). After reducing the problem to real variables, for the purpose 1) we develop a theory of time optimal syntheses for distributional problem on 2-D-manifolds, while for the purpose 2) we use techniques of subriemannian geometry on 3-D Lie groups. The complete optimal syntheses are computed. %B Discrete Contin. Dyn. Syst. Ser. B 5 (2005) 957-990 %G en_US %U http://hdl.handle.net/1963/2259 %1 1988 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-18T11:55:27Z\\nNo. of bitstreams: 1\\n0409022v2.pdf: 578605 bytes, checksum: db7298996e781c3a8546c3d01ee28384 (MD5) %0 Report %D 2005 %T Nonlinear Schrödinger Equations with vanishing and decaying potentials %A Antonio Ambrosetti %A Wang Zhi-Qiang %B Differential Integral Equations 18 (2005), no. 12, 1321-1332 %G en_US %U http://hdl.handle.net/1963/1760 %1 2784 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-03-22T09:32:48Z\\nNo. of bitstreams: 1\\n52M-2005.pdf: 2540023 bytes, checksum: a022763e63174283e8e626a5c191eb2a (MD5) %0 Report %D 2005 %T An Optimal Transportation Metric for Solutions of the Camassa-Holm Equation %A Alberto Bressan %A Massimo Fonte %X In this paper we construct a global, continuous flow of solutions to the Camassa-Holm equation on the entire space H1. Our solutions are conservative, in the sense that the total energy int[(u2 + u2x) dx] remains a.e. constant in time. Our new approach is based on a distance functional J(u, v), defined in terms of an optimal transportation problem, which satisfies d dtJ(u(t), v(t)) ≤ κ · J(u(t), v(t)) for every couple of solutions. Using this new distance functional, we can construct arbitrary solutions as the uniform limit of multi-peakon solutions, and prove a general uniqueness result. %B Methods Appl. Anal. 12 (2005) 191-219 %G en_US %U http://hdl.handle.net/1963/1719 %1 2432 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-01-24T09:03:54Z\\nNo. of bitstreams: 1\\nmath.AP0504450.pdf: 261370 bytes, checksum: 75945d031343a82836b46ab9705ed6de (MD5) %0 Thesis %D 2005 %T Orbifold Cohomology of ADE-singularities %A Fabio Perroni %K Orbifolds %I SISSA %G en %U http://hdl.handle.net/1963/5298 %1 5126 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-01-30T10:36:29Z\\r\\nNo. of bitstreams: 1\\r\\nPhD_Perroni_Fabio.pdf: 7453469 bytes, checksum: 82a5b59cbd1ef1a905a839ec06133c62 (MD5) %0 Journal Article %J Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 16 (2005), no. 2, 117-124 %D 2005 %T Periodic solutions of nonlinear wave equations with non-monotone forcing terms %A Massimiliano Berti %A Luca Biasco %B Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 16 (2005), no. 2, 117-124 %I Accademia Nazionale dei Lincei %G en %U http://hdl.handle.net/1963/4581 %1 4349 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-07T10:23:29Z\\nNo. of bitstreams: 1\\nBertiBiasco04-1.pdf: 267180 bytes, checksum: 2e0e4b98f4985c1e79dc4c03fb30618e (MD5) %0 Journal Article %J Comm. Math. Phys. 260 (2005) 203-225 %D 2005 %T Principal fibrations from noncommutative spheres %A Giovanni Landi %A Walter van Suijlekom %X We construct noncommutative principal fibrations S_\\\\theta^7 \\\\to S_\\\\theta^4 which are deformations of the classical SU(2) Hopf fibration over the four sphere. We realize the noncommutative vector bundles associated to the irreducible representations of SU(2) as modules of coequivariant maps and construct corresponding projections. The index of Dirac operators with coefficients in the associated bundles is computed with the Connes-Moscovici local index formula. The algebra inclusion $A(S_\\\\theta^4) \\\\into A(S_\\\\theta^7)$ is an example of a not trivial quantum principal bundle. %B Comm. Math. Phys. 260 (2005) 203-225 %G en_US %U http://hdl.handle.net/1963/2284 %1 1732 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-22T14:25:11Z\\nNo. of bitstreams: 1\\n0410077v3.pdf: 291352 bytes, checksum: 91d11a43e2221278d597a48ce274e4a5 (MD5) %R 10.1007/s00220-005-1377-7 %0 Journal Article %J Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 16 (2005), no. 2, 109-116 %D 2005 %T Quasi-periodic oscillations for wave equations under periodic forcing %A Massimiliano Berti %A Michela Procesi %B Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 16 (2005), no. 2, 109-116 %I Accademia Nazionale dei Lincei %G en %U http://hdl.handle.net/1963/4583 %1 4350 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-07T10:27:05Z\\nNo. of bitstreams: 1\\nBertiProcesi05-1.pdf: 211758 bytes, checksum: b6c3ae059191cddb5c025aee61a23799 (MD5) %0 Journal Article %J Arch. Ration. Mech. Anal. 176 (2005) 165-225 %D 2005 %T Quasistatic Crack Growth in Nonlinear Elasticity %A Gianni Dal Maso %A Gilles A. Francfort %A Rodica Toader %X In this paper, we prove a new existence result for a variational model of crack growth in brittle materials proposed in [15]. We consider the case of $n$-dimensional finite elasticity, for an arbitrary $n\\\\ge1$, with a quasiconvex bulk energy and with prescribed boundary deformations and applied loads, both depending on time. %B Arch. Ration. Mech. Anal. 176 (2005) 165-225 %G en_US %U http://hdl.handle.net/1963/2293 %1 1723 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-24T09:12:09Z\\nNo. of bitstreams: 1\\n0401196v1.pdf: 664295 bytes, checksum: cb1000c44e6ae356984e24b55ee97117 (MD5) %R 10.1007/s00205-004-0351-4 %0 Journal Article %J Journal of Mathematical Sciences 126 (2005) 1561-1573 %D 2005 %T Regularity properties of optimal trajectories of single-input control systems in dimension three %A Mario Sigalotti %X Let q=f(q)+ug(q) be a smooth control system on a three-dimensional manifold. Given a point q 0 of the manifold at which the iterated Lie brackets of f and g satisfy some prescribed independence condition, we analyze the structure of a control function u(t) corresponding to a time-optimal trajectory lying in a neighborhood of q 0. The control turns out to be the concatenation of some bang-bang and some singular arcs. More general optimality criteria than time-optimality are considered. The paper is a step toward to the analysis of generic single-input systems affine in the control in dimension 3. The main techniques used are second-order optimality conditions and, in particular, the index of the second variation of the switching times for bang-bang trajectories. %B Journal of Mathematical Sciences 126 (2005) 1561-1573 %I Springer %G en %U http://hdl.handle.net/1963/4794 %1 4564 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-17T08:06:19Z\\nNo. of bitstreams: 1\\nsuz.pdf: 199707 bytes, checksum: 1d18998eb7281177da4a442135d9b77d (MD5) %R 10.1007/s10958-005-0044-z %0 Journal Article %J Comput. Methods Appl. Mech. Engrg. 194 (2005) 2534-2549 %D 2005 %T Self-similar folding patterns and energy scaling in compressed elastic sheets %A Sergio Conti %A Antonio DeSimone %A Stefan Mueller %X Thin elastic sheets under isotropic compression, such as for example blisters formed by thin films which debonded from the substrate, can exhibit remarkably complex folding patterns. We discuss the scaling of the elastic energy with respect to the film thickness, and show that in certain regimes the optimal energy scaling can be reached\\nby self-similar folding patterns that refine towards the boundary, in agreement with experimental observations. We then extend the analysis\\nto anisotropic compression, and discuss a simplified scalar model which suggests the presence of a transition between a regime where\\nthe deformation is governed by global properties of the domain and another one where the direction of maximal compression dominates and the scale of the folds is mainly determined by the distance to the boundary in the direction of the folds themselves. %B Comput. Methods Appl. Mech. Engrg. 194 (2005) 2534-2549 %I Elsevier %G en_US %U http://hdl.handle.net/1963/3000 %1 1333 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-10-01T10:37:14Z\\nNo. of bitstreams: 1\\npreprint2004_3.pdf: 907333 bytes, checksum: 2b22c209b91ba2ddacc1a1c14a9054a2 (MD5) %R 10.1016/j.cma.2004.07.044 %0 Book Section %B Contrôle non linéaire et applications: Cours donnés à l\\\'école d\\\'été du Cimpa de l\\\'Université de Tlemcen / Sari Tewfit [ed.]. - Paris: Hermann, 2005 %D 2005 %T A short introduction to optimal control %A Ugo Boscain %A Benedetto Piccoli %B Contrôle non linéaire et applications: Cours donnés à l\\\'école d\\\'été du Cimpa de l\\\'Université de Tlemcen / Sari Tewfit [ed.]. - Paris: Hermann, 2005 %@ 2 7056 6511 0 %G en_US %U http://hdl.handle.net/1963/2257 %1 1990 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-18T11:30:24Z\\nNo. of bitstreams: 1\\nNotes-OptCont.pdf: 442775 bytes, checksum: 196e4d9cc52950dd18cf17feb0e89808 (MD5) %0 Generic %D 2005 %T Solutions of Neumann problems in domains with cracks and applications to fracture mechanics %A Gianni Dal Maso %G en_US %U http://hdl.handle.net/1963/1684 %1 79 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2005-05-20T07:18:38Z\\nNo. of bitstreams: 1\\nmath.AP0105132.pdf: 225826 bytes, checksum: d7308b70020a416522235ed54b404379 (MD5) %0 Journal Article %J C. R. Math. 340 (2005) 819-822 %D 2005 %T The spectral geometry of the equatorial Podles sphere %A Ludwik Dabrowski %A Giovanni Landi %A Mario Paschke %A Andrzej Sitarz %X We propose a slight modification of the properties of a spectral geometry a la Connes, which allows for some of the algebraic relations to be satisfied only modulo compact operators. On the equatorial Podles sphere we construct suq2-equivariant Dirac operator and real structure which satisfy these modified properties. %B C. R. Math. 340 (2005) 819-822 %G en_US %U http://hdl.handle.net/1963/2275 %1 1972 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-22T09:37:10Z\\nNo. of bitstreams: 1\\n0408034v2.pdf: 95565 bytes, checksum: 1c0e7836d4006a796eb943f128938773 (MD5) %R 10.1016/j.crma.2005.04.003 %0 Journal Article %J J. Math. Anal. Appl. 308 (2005) 221-239 %D 2005 %T Stability of solutions of quasilinear parabolic equations %A Giuseppe Maria Coclite %A Helge Holden %X We bound the difference between solutions $u$ and $v$ of $u_t = a\\\\Delta u+\\\\Div_x f+h$ and $v_t = b\\\\Delta v+\\\\Div_x g+k$ with initial data $\\\\phi$ and $ \\\\psi$, respectively, by $\\\\Vert u(t,\\\\cdot)-v(t,\\\\cdot)\\\\Vert_{L^p(E)}\\\\le A_E(t)\\\\Vert \\\\phi-\\\\psi\\\\Vert_{L^\\\\infty(\\\\R^n)}^{2\\\\rho_p}+ B(t)(\\\\Vert a-b\\\\Vert_{\\\\infty}+ \\\\Vert \\\\nabla_x\\\\cdot f-\\\\nabla_x\\\\cdot g\\\\Vert_{\\\\infty}+ \\\\Vert f_u-g_u\\\\Vert_{\\\\infty} + \\\\Vert h-k\\\\Vert_{\\\\infty})^{\\\\rho_p} \\\\abs{E}^{\\\\eta_p}$. Here all functions $a$, $f$, and $h$ are smooth and bounded, and may depend on $u$, $x\\\\in\\\\R^n$, and $t$. The functions $a$ and $h$ may in addition depend on $\\\\nabla u$. Identical assumptions hold for the functions that determine the solutions $v$. Furthermore, $E\\\\subset\\\\R^n$ is assumed to be a bounded set, and $\\\\rho_p$ and $\\\\eta_p$ are fractions that depend on $n$ and $p$. The diffusion coefficients $a$ and $b$ are assumed to be strictly positive and the initial data are smooth. %B J. Math. Anal. Appl. 308 (2005) 221-239 %I Elsevier %G en_US %U http://hdl.handle.net/1963/2892 %1 1808 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-10T12:48:15Z\\nNo. of bitstreams: 1\\n0306160v1.pdf: 240791 bytes, checksum: 4654ca0f7a1735bc7ee6666d37a2d57a (MD5) %R 10.1016/j.jmaa.2005.01.026 %0 Journal Article %J Int. J. Numer. Anal. Met. 29 (2005) 73-101 %D 2005 %T Stress-dilatancy based modelling of granular materials and extensions to soils with crushable grains %A Antonio DeSimone %A Claudio Tamagnini %X Stress-dilatancy relations have played a crucial role in the understanding of the mechanical behaviour of soils and in the development of realistic constitutive models for their response. Recent investigations on the mechanical behaviour of materials with crushable grains have called into question the validity of classical relations such as those used in critical state soil mechanics.\\nIn this paper, a method to construct thermodynamically consistent (isotropic, three-invariant) elasto-plastic models based on a given stress-dilatancy relation is discussed. Extensions to cover the case of granular materials with crushable grains are also presented, based on the interpretation of some classical model parameters (e.g. the stress ratio at critical state) as internal variables that evolve according to suitable hardening laws. %B Int. J. Numer. Anal. Met. 29 (2005) 73-101 %G en_US %U http://hdl.handle.net/1963/2165 %1 2079 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-02T12:02:04Z\\nNo. of bitstreams: 1\\nDeSimoneTamagnini_2005.pdf: 1179767 bytes, checksum: 23b892b2314ea8e2199cc2b2449386b0 (MD5) %R 10.1002/nag.405 %0 Report %D 2005 %T Time minimal trajectories for two-level quantum systems with drift %A Ugo Boscain %A Paolo Mason %X On a two-level quantum system driven by an external field, we consider the population transfer problem from the first to the second level, minimizing the time of transfer, with bounded field amplitude. On the Bloch sphere (i.e. after a suitable Hopf projection), this problem can be attacked with techniques of optimal syntheses on 2-D manifolds. %B Decision and Control, 2005 and 2005 European Control Conference. CDC-ECC \\\'05. 44th IEEE Conference on %G en_US %U http://hdl.handle.net/1963/1688 %1 2445 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2005-06-20T12:25:55Z\\nNo. of bitstreams: 1\\nquant-ph0502151.pdf: 136766 bytes, checksum: d23bf76326e4a9a09555f4ead6edc808 (MD5) %0 Journal Article %J SIAM J. Control Optim. 44 (2005) 111-139 %D 2005 %T Time Optimal Synthesis for Left-Invariant Control Systems on SO(3) %A Ugo Boscain %A Yacine Chitour %X Consider the control system given by $\\\\dot x=x(f+ug)$, where $x\\\\in SO(3)$, $|u|\\\\leq 1$ and $f,g\\\\in so(3)$ define two perpendicular left-invariant vector fields normalized so that $\\\\|f\\\\|=\\\\cos(\\\\al)$ and $\\\\|g\\\\|=\\\\sin(\\\\al)$, $\\\\al\\\\in ]0,\\\\pi/4[$. In this paper, we provide an upper bound and a lower bound for $N(\\\\alpha)$, the maximum number of switchings for time-optimal trajectories. More precisely, we show that $N_S(\\\\al)\\\\leq N(\\\\al)\\\\leq N_S(\\\\al)+4$, where $N_S(\\\\al)$ is a suitable integer function of $\\\\al$ which for $\\\\al\\\\to 0$ is of order $\\\\pi/(4\\\\alpha).$ The result is obtained by studying the time optimal synthesis of a projected control problem on $R P^2$, where the projection is defined by an appropriate Hopf fibration. Finally, we study the projected control problem on the unit sphere $S^2$. It exhibits interesting features which will be partly rigorously derived and partially described by numerical simulations. %B SIAM J. Control Optim. 44 (2005) 111-139 %G en_US %U http://hdl.handle.net/1963/2258 %1 1989 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-18T11:43:01Z\\nNo. of bitstreams: 1\\n0502483v1.pdf: 429552 bytes, checksum: 9f72f53d7031cdc7ccb2aca8b8ec16de (MD5) %R 10.1137/S0363012904441532 %0 Report %D 2005 %T Topological vector symmetry, topological gauge fixing of BRSTQFT and construction of maximal supersymmetry %A Laurent Baulieu %A Guillaume Bossard %A Alessandro Tanzini %X The scalar and vector topological Yang-Mills symmetries determine a closed and consistent sector of Yang-Mills supersymmetry. We provide a geometrical construction of these symmetries, based on a horizontality condition on reducible manifolds. This yields globally well-defined scalar and vector topological BRST operators. These operators generate a subalgebra of maximally supersymmetric Yang-Mills theory, which is small enough to be closed off-shell with a finite set of auxiliary fields and large enough to determine the Yang-Mills supersymmetric theory. Poincaré supersymmetry is reached in the limit of flat manifolds. The arbitrariness of the gauge functions in BRSTQFTs is thus removed by the requirement of scalar and vector topological symmetry, which also determines the complete supersymmetry transformations in a twisted way. Provided additional Killing vectors exist on the manifold, an equivariant extension of our geometrical framework is provided, and the resulting \\\"equivariant topological field theory\\\" corresponds to the twist of super Yang-Mills theory on omega backgrounds. %B JHEP 0508 (2005) 037 %G en_US %U http://hdl.handle.net/1963/1741 %1 2411 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2006-02-23T10:07:01Z\\nNo. of bitstreams: 1\\nhep-th0504224.pdf: 434040 bytes, checksum: 925f48080ebdefb366d603cd196cba76 (MD5) %R 10.1088/1126-6708/2005/08/037 %0 Journal Article %J SIAM J. Math. Anal. 36 (2005) 1862-1886 %D 2005 %T Traffic flow on a road network %A Giuseppe Maria Coclite %A Benedetto Piccoli %A Mauro Garavello %X This paper is concerned with a fluidodynamic model for traffic flow. More precisely, we consider a single conservation law, deduced from conservation of the number of cars,\\ndefined on a road network that is a collection of roads with junctions. The evolution problem is underdetermined at junctions, hence we choose to have some fixed rules for the distribution of traffic plus an optimization criteria for the flux. We prove existence, uniqueness and stability of solutions to the Cauchy problem. Our method is based on wave front tracking approach, see [6], and works also for boundary data and time dependent coefficients of traffic distribution at junctions, so including traffic lights. %B SIAM J. Math. Anal. 36 (2005) 1862-1886 %I SISSA Library %G en %U http://hdl.handle.net/1963/1584 %1 2534 %2 Mathematics %3 Functional Analysis and Applications %$ Made available in DSpace on 2004-09-01T13:04:54Z (GMT). No. of bitstreams: 1\\nmath.AP0202146.pdf: 256961 bytes, checksum: 51f64ff00e916dd87d3dd6df41903d23 (MD5)\\n Previous issue date: 2002 %R 10.1137/S0036141004402683 %0 Journal Article %J Ann. of Math. 161 (2005) 223-342 %D 2005 %T Vanishing viscosity solutions of nonlinear hyperbolic systems %A Stefano Bianchini %A Alberto Bressan %X We consider the Cauchy problem for a strictly hyperbolic, $n\\\\times n$ system in one space dimension: $u_t+A(u)u_x=0$, assuming that the initial data has small total variation.\\nWe show that the solutions of the viscous approximations $u_t+A(u)u_x=\\\\ve u_{xx}$ are defined globally in time and satisfy uniform BV estimates, independent of $\\\\ve$. Moreover, they depend continuously on the initial data in the $\\\\L^1$ distance, with a Lipschitz constant independent of $t,\\\\ve$. Letting $\\\\ve\\\\to 0$, these viscous solutions converge to a unique limit, depending Lipschitz continuously on the initial data. In the conservative case where $A=Df$ is the Jacobian of some flux function $f:\\\\R^n\\\\mapsto\\\\R^n$, the vanishing viscosity limits are precisely the unique entropy weak solutions to the system of conservation laws $u_t+f(u)_x=0$. %B Ann. of Math. 161 (2005) 223-342 %I Annals of Mathematics %G en_US %U http://hdl.handle.net/1963/3074 %1 1259 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-10-10T10:46:16Z\\nNo. of bitstreams: 1\\n0111321v1.pdf: 746310 bytes, checksum: f3b7c9e76e33050e9f367ba2c57e2161 (MD5) %0 Journal Article %J Proc. R. Soc. Lon. Ser. A 461 (2005) 79-97 %D 2005 %T Wetting of rough surfaces: a homogenization approach %A Antonio DeSimone %A Giovanni Alberti %X The contact angle of a drop in equilibrium on a solid is strongly affected by the roughness of the surface on which it rests. We study the roughness-induced enhancement of the hydrophobic or hydrophilic properties of a solid surface through homogenization theory. By relying on a variational formulation of the problem, we show that the macroscopic contact angle is associated with the solution of two cell problems, giving the minimal energy per unit macroscopic area for a transition layer between the rough solid surface and a liquid or vapor phase. Our results are valid for both chemically heterogeneous and homogeneous surfaces. In the latter case, a very transparent structure emerges from the variational\\napproach: the classical laws of Wenzel and Cassie-Baxter give bounds for the optimal energy, and configurations of minimal energy are those leading to the smallest macroscopic contact angle in the hydrophobic case, to the largest one in the hydrophilic case. %B Proc. R. Soc. Lon. Ser. A 461 (2005) 79-97 %G en_US %U http://hdl.handle.net/1963/2253 %1 1994 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-18T07:46:26Z\\nNo. of bitstreams: 1\\n75-04.pdf: 370259 bytes, checksum: 3ac1bc80248a4e54ff5294b7baffa66f (MD5) %R 10.1098/rspa.2004.1364 %0 Journal Article %J Amer. Math. Soc. Transl. 212 (2004)\\n75-132. %D 2004 %T On almost duality for Frobenius manifolds %A Boris Dubrovin %X We present a universal construction of almost duality for Frobenius manifolds. The analytic setup of this construction is described in details for the case of semisimple Frobenius manifolds. We illustrate the general considerations by examples from the singularity theory, mirror symmetry, the theory of Coxeter groups and Shephard groups, from the Seiberg - Witten duality. %B Amer. Math. Soc. Transl. 212 (2004)\\n75-132. %G en_US %U http://hdl.handle.net/1963/2543 %1 1576 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-12-21T12:40:01Z\\nNo. of bitstreams: 1\\n0307374v2.pdf: 617411 bytes, checksum: 7c8c52a06ea53850475a3e7055ce9af1 (MD5) %0 Journal Article %J Astérisque. Issue 297, 2004, Pages 35-65 %D 2004 %T On analytic families of invariant tori for PDEs %A Boris Dubrovin %X We propose to apply a version of the classical Stokes\\r\\nexpansion method to the perturbative construction of invariant tori for\\r\\nPDEs corresponding to solutions quasiperiodic in space and time variables.\\r\\nWe argue that, for integrable PDEs all but finite number of the\\r\\nsmall divisors arising in the perturbative analysis cancel. As an illustrative\\r\\nexample we establish such cancellations for the case of KP equation.\\r\\nIt is proved that, under mild assumptions about decay of the magnitude\\r\\nof the Fourier modes all analytic families of finite-dimensional invariant\\r\\ntori for KP are given by the Krichever construction in terms of thetafunctions\\r\\nof Riemann surfaces. We also present an explicit construction\\r\\nof infinite dimensional real theta-functions and corresponding quasiperiodic\\r\\nsolutions to KP as sums of infinite number of interacting plane\\r\\nwaves. %B Astérisque. Issue 297, 2004, Pages 35-65 %I SISSA %G en %U http://hdl.handle.net/1963/6474 %1 6420 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Boris Dubrovin (dubrovin@sissa.it) on 2013-02-11T14:58:35Z\\nNo. of bitstreams: 1\\ndubrovin_2004_asterisque.pdf: 318797 bytes, checksum: 3fe6968166d8ac662d44abd508bde574 (MD5) %0 Journal Article %J Ann. Inst. H. Poincaré. Anal. Non Linéaire 21 (2004), (4), p. 445-486. %D 2004 %T Asymptotic behaviour and correctors for linear Dirichlet problems with simultaneously varying operators and domains %A Gianni Dal Maso %A Francois Murat %X We consider a sequence of Dirichlet problems in varying domains (or, more generally, of relaxed Dirichlet problems involving measures in M_0) for second order linear elliptic operators in divergence form with varying matrices of coefficients. When the matrices H-converge to a matrix A^0, we prove that there exist a subsequence and a measure mu^0 in M_0 such that the limit problem is the relaxed Dirichlet problem corresponding to A^0 and mu^0. We also prove a corrector result which provides an explicit approximation of the solutions in the H^1-norm, and which is obtained by multiplying the corrector for the H-converging matrices by some special test function which depends both on the varying matrices and on the varying domains. %B Ann. Inst. H. Poincaré. Anal. Non Linéaire 21 (2004), (4), p. 445-486. %I SISSA Library %G en %U http://hdl.handle.net/1963/1611 %1 2507 %2 Mathematics %3 Functional Analysis and Applications %$ Made available in DSpace on 2004-09-01T13:05:17Z (GMT). No. of bitstreams: 1\\r\\nmath.AP0205225.pdf: 404809 bytes, checksum: 472524cb28afed2e55fcf0a7c46e7598 (MD5)\\r\\n Previous issue date: 2002 %0 Journal Article %J Boll. Unione Mat. Ital. Sez. B 7 (2004) 519-528 %D 2004 %T Bifurcation of free vibrations for completely resonant wave equations %A Massimiliano Berti %A Philippe Bolle %X We prove existence of small amplitude, 2 pi/omega -periodic in time solutions of completely resonant nonlinear wave equations with Dirichlet boundary conditions for any frequency omega belonging to a Cantor-like set of positive measure and for a generic set of nonlinearities. The proof relies on a suitable Lyapunov-Schmidt decomposition and a variant of the Nash-Moser Implicit Function Theorem. %B Boll. Unione Mat. Ital. Sez. B 7 (2004) 519-528 %G en_US %U http://hdl.handle.net/1963/2245 %1 1999 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-17T09:55:20Z\\nNo. of bitstreams: 1\\n0409052v1.pdf: 145050 bytes, checksum: 68913e2c100ffa7488447933554c30e7 (MD5) %0 Journal Article %J Ann. Inst. H. Poincare Anal. Non Lineaire 21 (2004) 121-137 %D 2004 %T Blow-up solutions for the Schrödinger equation in dimension three with a concentrated nonlinearity %A Riccardo Adami %A Gianfausto Dell'Antonio %A Rodolfo Figari %A Alessandro Teta %X We present some results on the blow-up phenomenon for the Schroedinger equation in dimension three with a nonlinear term supported in a fixed point. We find sufficient conditions for the blow up exploiting the moment of inertia of the solution and the uncertainty principle. In the critical case, we discuss the additional symmetry of the equation and construct a family of explicit blow up solutions. %B Ann. Inst. H. Poincare Anal. Non Lineaire 21 (2004) 121-137 %I Elsevier %G en_US %U http://hdl.handle.net/1963/2998 %1 1335 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-10-01T10:06:49Z\\nNo. of bitstreams: 1\\nadami.pdf: 209114 bytes, checksum: ea6a7059ff0728c6d55cdc3a16071631 (MD5) %R 10.1016/j.anihpc.2003.01.002 %0 Journal Article %J Int. J. Numer. Meth. Fluids %D 2004 %T Calculation of impulsively started incompressible viscous flows %A Marra, Andrea %A Mola, Andrea %A Quartapelle, Luigi %A Riviello, Luca %B Int. J. Numer. Meth. Fluids %V 46 %P 877–902 %G eng %0 Journal Article %J Computer methods in applied mechanics and engineering , 193 (2004) 5129-5141 %D 2004 %T Coarse-grained models of materials with non-convex free-energy: two case studies %A Antonio DeSimone %X Bridging across length scales is one of the fundamental challenges in the computational modelling of material systems whose mechanical response is driven by rough energy landscapes. The typical feature of such systems is that of exhibiting fine scale microstructures. Two case studies, namely, nematic elastomers and ferromagnetic shape memory alloys, are presented to illustrate the use of modern techniques from (non-convex) calculus of variations in developing coarse-grained models of microstructure-driven material response. %B Computer methods in applied mechanics and engineering , 193 (2004) 5129-5141 %I Elsevier %G en %U http://hdl.handle.net/1963/4884 %1 4664 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-24T06:59:37Z\\nNo. of bitstreams: 0 %R 10.1016/j.cma.2003.12.064 %0 Journal Article %J Phys. Rev. A 70 (2004) 062321 %D 2004 %T Coherent control of open quantum dynamical systems %A Claudio Altafini %X A systematic analysis of the behavior of the quantum Markovian master equation driven by coherent control fields is proposed. Its irreversible character is formalized using control-theoretic notions and the sets of states that can be reached via cohere nt controls are described. The analysis suggests to which extent (and how) it is possible to counteract the effect of dissipation. %B Phys. Rev. A 70 (2004) 062321 %G en_US %U http://hdl.handle.net/1963/2227 %1 2017 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-15T14:29:53Z\\nNo. of bitstreams: 1\\nqopen-coher2.pdf: 226720 bytes, checksum: c93d394691258c3d18b40d7992b70274 (MD5) %R 10.1103/PhysRevA.70.062321 %0 Journal Article %J Comm. Pure Appl. Math. 57 (2004) 1075-1109 %D 2004 %T On the convergence rate of vanishing viscosity approximations %A Alberto Bressan %A Tong Yang %X Given a strictly hyperbolic, genuinely nonlinear system of conservation laws, we prove the a priori bound $\\\\big\\\\|u(t,\\\\cdot)-u^\\\\ve(t,\\\\cdot)\\\\big\\\\|_{\\\\L^1}= \\\\O(1)(1+t)\\\\cdot \\\\sqrt\\\\ve|\\\\ln\\\\ve|$ on the distance between an exact BV solution $u$ and a viscous approximation $u^\\\\ve$, letting the viscosity coefficient $\\\\ve\\\\to 0$. In the proof, starting from $u$ we construct an approximation of the viscous solution $u^\\\\ve$ by taking a mollification $u*\\\\phi_{\\\\strut \\\\sqrt\\\\ve}$ and inserting viscous shock profiles at the locations of finitely many large shocks, for each fixed $\\\\ve$. Error estimates are then obtained by introducing new Lyapunov functionals which control shock interactions, interactions between waves of different families and by using sharp decay estimates for positive nonlinear waves. %B Comm. Pure Appl. Math. 57 (2004) 1075-1109 %I Wiley %G en_US %U http://hdl.handle.net/1963/2915 %1 1785 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-11T13:30:25Z\\nNo. of bitstreams: 1\\nmath.AP0307141.pdf: 265243 bytes, checksum: 795adebd067228364ac1240add5f7b02 (MD5) %R 10.1002/cpa.20030 %0 Conference Proceedings %B Théories asymptotiques et équations de Painlevé : [colloque], Angers, juin 2004 / édité par Éric Delabaere, Michèle Loday-Richaud. - Paris : Société mathématique de France, 2006. - Collection SMF. Séminaires et congrès. - page : 83-101 %D 2004 %T The elliptic representation of the sixth Painlevé equation. %A Davide Guzzetti %K Painlevé equation %X We find a class of solutions of the sixth Painlev´e equation corresponding\r\nto almost all the monodromy data of the associated linear system; actually, all data\r\nbut one point in the space of data. We describe the critical behavior close to the\r\ncritical points by means of the elliptic representation, and we find the relation among\r\nthe parameters at the different critical points (connection problem). %B Théories asymptotiques et équations de Painlevé : [colloque], Angers, juin 2004 / édité par Éric Delabaere, Michèle Loday-Richaud. - Paris : Société mathématique de France, 2006. - Collection SMF. Séminaires et congrès. - page : 83-101 %I Societe Matematique de France %@ 978-2-85629-229-7 %G en %U http://hdl.handle.net/1963/6529 %1 6482 %2 Mathematics %4 1 %# MAT/07 FISICA MATEMATICA %$ Submitted by Davide Guzzetti (guzzetti@sissa.it) on 2013-03-13T10:22:07Z\nNo. of bitstreams: 1\n10-SemCongSMF06.pdf: 299143 bytes, checksum: dc2b0ca561808604467132b9b5942fe3 (MD5) %0 Journal Article %J M2AN Math. Model. Numer. Anal. 38 (2004) 235-248 %D 2004 %T Energetics and switching of quasi-uniform states in small ferromagnetic particles %A Francois Alouges %A Sergio Conti %A Antonio DeSimone %A Ivo Pokern %X We present a numerical algorithm to solve the micromagnetic equations based on tangential-plane minimization for the magnetization update and a homothethic-layer decomposition of outer space for the computation of the demagnetization field. As a first application, detailed results on the flower-vortex transition in the cube of Micromagnetic Standard Problem number 3 are obtained, which confirm, with a different method, those already present in the literature, and validate our method and code. We then turn to switching of small cubic or almost-cubic particles, in the single-domain limit. Our data show systematic deviations from the Stoner-Wohlfarth model due to the non-ellipsoidal shape of the particle, and in particular a non-monotone dependence on the particle size. %B M2AN Math. Model. Numer. Anal. 38 (2004) 235-248 %I EDP Sciences %G en_US %U http://hdl.handle.net/1963/2999 %1 1334 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-10-01T10:25:50Z\\nNo. of bitstreams: 1\\npreprint2003_88.pdf: 297354 bytes, checksum: d907d5a9d74d0a3dcb244e26ff2af68a (MD5) %R 10.1051/m2an:2004011 %0 Journal Article %J Rev. Mat. Iberoamericana 20 (2004) 611-626 %D 2004 %T Existence of H-bubbles in a perturbative setting %A Paolo Caldiroli %A Roberta Musina %X Given a $C^{1}$ function $H: \\\\mathbb{R}^3 \\\\to \\\\mathbb{R}$, we look for $H$-bubbles, i.e., surfaces in $\\\\mathbb{R}^3$ parametrized by the sphere $\\\\mathbb{S}^2$ with mean curvature $H$ at every regular point. Here we study the case $H(u)=H_{0}(u)+\\\\epsilon H_{1}(u)$ where $H_{0}$ is some \\\"good\\\" curvature (for which there exist $H_{0}$-bubbles with minimal energy, uniformly bounded in $L^{\\\\infty}$), $\\\\epsilon$ is the smallness parameter, and $H_{1}$ is {\\\\em any} $C^{1}$ function. %B Rev. Mat. Iberoamericana 20 (2004) 611-626 %I SISSA Library %G en %U http://hdl.handle.net/1963/1606 %1 2512 %2 Mathematics %3 Functional Analysis and Applications %$ Made available in DSpace on 2004-09-01T13:05:13Z (GMT). No. of bitstreams: 0\\n Previous issue date: 2002 %0 Journal Article %J Moscow Math. J. 4 (2004)\\n313-332. %D 2004 %T The Extended Toda Hierarchy %A Guido Carlet %A Boris Dubrovin %A Zhang Youjin %B Moscow Math. J. 4 (2004)\\n313-332. %G en_US %U http://hdl.handle.net/1963/2542 %1 1577 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-12-21T12:22:27Z\\nNo. of bitstreams: 1\\n0306060v2.pdf: 242352 bytes, checksum: 7a4fc53dbf549eb7046e75be6c087368 (MD5) %0 Journal Article %J J. Geom. Phys. 49 (2004) 272-293 %D 2004 %T Fredholm modules for quantum euclidean spheres %A Eli Hawkins %A Giovanni Landi %X The quantum Euclidean spheres, $S_q^{N-1}$, are (noncommutative) homogeneous spaces of quantum orthogonal groups, $\\\\SO_q(N)$. The *-algebra $A(S^{N-1}_q)$ of polynomial functions on each of these is given by generators and relations which can be expressed in terms of a self-adjoint, unipotent matrix. We explicitly construct complete sets of generators for the K-theory (by nontrivial self-adjoint idempotents and unitaries) and the K-homology (by nontrivial Fredholm modules) of the spheres $S_q^{N-1}$. We also construct the corresponding Chern characters in cyclic homology and cohomology and compute the pairing of K-theory with K-homology. On odd spheres (i. e., for N even) we exhibit unbounded Fredholm modules by means of a natural unbounded operator D which, while failing to have compact resolvent, has bounded commutators with all elements in the algebra $A(S^{N-1}_q)$. %B J. Geom. Phys. 49 (2004) 272-293 %I SISSA Library %G en %U http://hdl.handle.net/1963/1636 %1 2482 %2 Mathematics %3 Mathematical Physics %$ Made available in DSpace on 2004-09-01T13:05:40Z (GMT). No. of bitstreams: 1\\nmath.KT0210139.pdf: 218018 bytes, checksum: 44f0c66ef47d8b2e1cafc955075c7626 (MD5)\\n Previous issue date: 2002 %R 10.1016/S0393-0440(03)00092-5 %0 Journal Article %J Differential Geom. Appl. 21 (2004) 349-360 %D 2004 %T A geometric approach to the separability of the Neumann-Rosochatius system %A Claudio Bartocci %A Gregorio Falqui %A Marco Pedroni %X We study the separability of the Neumann-Rosochatius system on the n-dimensional sphere using the geometry of bi-Hamiltonian manifolds. Its well-known separation variables are recovered by means of a separability condition relating the Hamiltonian with a suitable (1,1) tensor field on the sphere. This also allows us to iteratively construct the integrals of motion of the system. %B Differential Geom. Appl. 21 (2004) 349-360 %G en_US %U http://hdl.handle.net/1963/2541 %1 1578 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-12-21T11:58:45Z\\nNo. of bitstreams: 1\\n0307021v1.pdf: 200686 bytes, checksum: 8df72df9ec62154c01c13bf79577d97c (MD5) %R 10.1016/j.difgeo.2004.07.001 %0 Journal Article %J Duke Math. J. 122 (2004), no. 3, 457--484 %D 2004 %T H-bubbles in a perturbative setting: the finite-dimensional reduction\\\'s method %A Paolo Caldiroli %A Roberta Musina %X Given a regular function $H\\\\colon\\\\mathbb{R}^{3}\\\\to\\\\mathbb{R}$, we look for $H$-bubbles, that is, regular surfaces in $\\\\mathbb{R}^{3}$ parametrized on the sphere $\\\\mathbb{S}+^{2}$ with mean curvature $H$ at every point. Here we study the case of $H(u)=H_{0}+\\\\varepsilon H_{1}(u)=:H_{\\\\varepsilon}(u)$, where $H_{0}$ is a nonzero constant, $\\\\varepsilon$ is the smallness parameter, and $H_{1}$ is any $C^{2}$-function. We prove that if $\\\\bar p\\\\in\\\\mathbb{R}^{3}$ is a ``good\\\'\\\' stationary point for the Melnikov-type function $\\\\Gamma(p)=-\\\\int_{|q-p|<|H_{0}|^{-1}}H_{1}(q)\\\\,dq$, then for $|\\\\varepsilon|$ small there exists an $H_{\\\\varepsilon}$-bubble $\\\\omega^{\\\\varepsilon}$ that converges to a sphere of radius $|H_{0}|^{-1}$ centered at $\\\\bar p$, as $\\\\varepsilon\\\\to 0$. %B Duke Math. J. 122 (2004), no. 3, 457--484 %I SISSA Library %G en %U http://hdl.handle.net/1963/1607 %1 2511 %2 Mathematics %3 Functional Analysis and Applications %$ Made available in DSpace on 2004-09-01T13:05:13Z (GMT). No. of bitstreams: 0\\n Previous issue date: 2002 %R 10.1215/S0012-7094-04-12232-8 %0 Journal Article %J Arch. Ration. Mech. Anal. 171 (2004) 55-81 %D 2004 %T Higher order quasiconvexity reduces to quasiconvexity %A Gianni Dal Maso %A Irene Fonseca %A Giovanni Leoni %A Massimiliano Morini %X In this paper it is shown that higher order quasiconvex functions suitable in the variational treatment of problems involving second derivatives may be extended to the space of all matrices as classical quasiconvex functions. Precisely, it is proved that a smooth strictly 2-quasiconvex function with p-growth at infinity, p>1, is the restriction to symmetric matrices of a 1-quasiconvex function with the same growth. As a consequence, lower semicontinuity results for second-order variational problems are deduced as corollaries of well-known first order theorems. %B Arch. Ration. Mech. Anal. 171 (2004) 55-81 %I Springer %G en_US %U http://hdl.handle.net/1963/2911 %1 1789 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-11T12:36:19Z\\nNo. of bitstreams: 1\\nmath.AP0305138.pdf: 272082 bytes, checksum: 245f93702444ac3eb1de7c86c1f83551 (MD5) %R 10.1007/s00205-003-0278-1 %0 Conference Proceedings %B 43rd IEEE Conference on Decision and Control, 2004, 2786 - 2791 Vol.3 %D 2004 %T On the minimal degree of a common Lyapunov function for planar switched systems %A Paolo Mason %A Ugo Boscain %A Yacine Chitour %X In this paper, we consider linear switched systems x(t) = Au(t)x(t), x ε Rn, u ε U, and the problem of asymptotic stability for arbitrary switching functions, uniform with respect to switching (UAS for short). We first prove that, given a UAS system, it is always possible to build a polynomial common Lyapunov function. Then our main result is that the degree of that the common polynomial Lyapunov function is not uniformly bounded over all the UAS systems. This result answers a question raised by Dayawansa and Martin. %B 43rd IEEE Conference on Decision and Control, 2004, 2786 - 2791 Vol.3 %I IEEE %G en %U http://hdl.handle.net/1963/4834 %1 4611 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-19T07:47:35Z\\nNo. of bitstreams: 0 %R 10.1109/CDC.2004.1428884 %0 Journal Article %J Duke Math. J. 124 (2004) 105-143 %D 2004 %T Multidimensional boundary layers for a singularly perturbed Neumann problem %A Andrea Malchiodi %A Marcelo Montenegro %B Duke Math. J. 124 (2004) 105-143 %I Duke University Press %G en_US %U http://hdl.handle.net/1963/2960 %1 1740 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-22T08:57:55Z\\nNo. of bitstreams: 1\\nMalchiodiMontenegro03.pdf: 414971 bytes, checksum: a647d87b29bbf0808629d5647dfd1dad (MD5) %R 10.1215/S0012-7094-04-12414-5 %0 Journal Article %J Nonlinear Anal. 56 (2004) 1011-1046 %D 2004 %T Multiplicity of periodic solutions of nonlinear wave equations %A Massimiliano Berti %A Philippe Bolle %B Nonlinear Anal. 56 (2004) 1011-1046 %I Elsevier %G en_US %U http://hdl.handle.net/1963/2974 %1 1359 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-29T12:46:01Z\\nNo. of bitstreams: 1\\nBertiBolle04.pdf: 387346 bytes, checksum: 6374d2229ca34f3936e690a01f4b4eab (MD5) %R 10.1016/j.na.2003.11.001 %0 Journal Article %J Ann. Sc. Norm. Super. Pisa Cl. Sci. (5) 3 (2004) 87-138 %D 2004 %T Periodic orbits close to elliptic tori and applications to the three-body problem %A Massimiliano Berti %A Luca Biasco %A Enrico Valdinoci %X We prove, under suitable non-resonance and non-degeneracy ``twist\\\'\\\' conditions, a Birkhoff-Lewis type result showing the existence of infinitely many periodic solutions, with larger and larger minimal period, accumulating onto elliptic invariant tori (of Hamiltonian systems). We prove the applicability of this result to the spatial planetary three-body problem in the small eccentricity-inclination regime. Furthermore, we find other periodic orbits under some restrictions on the period and the masses of the ``planets\\\'\\\'. The proofs are based on averaging theory, KAM theory and variational methods. (Supported by M.U.R.S.T. Variational Methods and Nonlinear Differential Equations.) %B Ann. Sc. Norm. Super. Pisa Cl. Sci. (5) 3 (2004) 87-138 %I Scuola Normale Superiore di Pisa %G en_US %U http://hdl.handle.net/1963/2985 %1 1348 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-30T09:03:01Z\\nNo. of bitstreams: 1\\n0304103v1.pdf: 482533 bytes, checksum: 5da7f32109202edb44f004885b665b48 (MD5) %0 Journal Article %J Quad. Mat. Dip. Mat. Seconda Univ. Napoli 14 (2004) 245-266 %D 2004 %T Quasi-static evolution in brittle fracture: the case of bounded solutions %A Gianni Dal Maso %A Gilles A. Francfort %A Rodica Toader %X The main steps of the proof of the existence result for the quasi-static evolution of cracks in brittle materials, obtained in [7] in the vector case and for a general quasiconvex elastic energy, are presented here under the simplifying assumption that the minimizing sequences involved in the problem are uniformly bounded in $L^\\\\infty$. %B Quad. Mat. Dip. Mat. Seconda Univ. Napoli 14 (2004) 245-266 %G en_US %U http://hdl.handle.net/1963/2229 %1 2015 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-15T15:04:28Z\\r\\nNo. of bitstreams: 1\\r\\n0401198v1.pdf: 166634 bytes, checksum: c21fba2b1fbbaec4fe14c56595b0664e (MD5) %0 Journal Article %J ESAIM: COCV 10 (2004) 526-548 %D 2004 %T Reduction by group symmetry of second order variational problems on a semidirect product of Lie groups with positive definite Riemannian metric %A Claudio Altafini %X For a Riemannian structure on a semidirect product of Lie groups, the variational problems can be reduced using the group symmetry. Choosing the Levi-Civita connection of a positive definite metric tensor, instead of any of the canonical connections for the Lie group, simplifies the reduction of the variations but complicates the expression for the Lie algebra valued covariant derivatives. The origin of the discrepancy is in the semidirect product structure, which implies that the Riemannian exponential map and the Lie group exponential map do not coincide. The consequence is that the reduced equations look more complicated than the original ones. The main scope of this paper is to treat the reduction of second order variational problems (corresponding to geometric splines) on such semidirect products of Lie groups. Due to the semidirect structure, a number of extra terms appears in the reduction, terms that are calculated explicitely. The result is used to compute the necessary conditions of an optimal control problem for a simple mechanical control system having invariant Lagrangian equal to the kinetic energy corresponding to the metric tensor. As an example, the case of a rigid body on the Special Euclidean group is considered in detail. %B ESAIM: COCV 10 (2004) 526-548 %I EDP Sciences %G en_US %U http://hdl.handle.net/1963/3521 %1 743 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-02-18T11:36:09Z\\nNo. of bitstreams: 1\\ncocv0318.pdf: 296243 bytes, checksum: d9c2fc54e6a7b051fd350dfc5556c06e (MD5) %R 10.1051/cocv:2004018 %0 Journal Article %J Phys. Rev. A 70 (2004) 032331 %D 2004 %T Representing multiqubit unitary evolutions via Stokes tensors %A Claudio Altafini %X For the Stokes tensor parametrization of a multiqubit density operator, we provide an explicit formulation of the corresponding unitary dynamics at the infinitesimal level. The main advantage of this formalism (clearly reminiscent of the ideas of ``coherences\\\'\\\' and ``coupling Hamiltonians\\\'\\\' of spin systems) is that the pattern of correlation between qubits and the pattern of infinitesimal correlation are highlighted simultaneously and can be used constructively for qubit manipulation. For example, it allows to compute explicitly a Rodrigues\\\' formula for the one-parameter orbits of nonlocal Hamiltonians. The result is easily generalizable to orbits of Cartan subalgebras and allows to express the Cartan decomposition of unitary propagators as a linear action directly in terms of the infinitesimal generators. %B Phys. Rev. A 70 (2004) 032331 %G en_US %U http://hdl.handle.net/1963/2307 %1 1709 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-10-29T12:24:28Z\\nNo. of bitstreams: 1\\n0404006v2.pdf: 225292 bytes, checksum: 7e44f5dc452e09ecabe9744c757b4b03 (MD5) %R 10.1103/PhysRevA.70.032331 %0 Journal Article %J ESAIM COCV 10 (2004) 593-614 %D 2004 %T Resonance of minimizers for n-level quantum systems with an arbitrary cost %A Ugo Boscain %A Grégoire Charlot %X We consider an optimal control problem describing a laser-induced population transfer on a $n$-level quantum system.\\nFor a convex cost depending only on the moduli of controls (i.e. the lasers intensities), we prove that there always exists a minimizer in resonance. This permits to justify some strategies used in experimental physics. It is also quite important because it permits to reduce remarkably the complexity of the problem (and extend some of our previous results for $n=2$ and $n=3$): instead of looking for minimizers on the sphere $S^{2n-1}\\\\subset\\\\C^n$ one is reduced to look just for minimizers on the sphere $S^{n-1}\\\\subset \\\\R^n$. Moreover, for the reduced problem, we investigate on the question of existence of strict abnormal minimizer. %B ESAIM COCV 10 (2004) 593-614 %I EDP Sciences %G en_US %U http://hdl.handle.net/1963/2910 %1 1790 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-11T12:22:45Z\\nNo. of bitstreams: 1\\n0308103v2.pdf: 290972 bytes, checksum: 2195a0a0002da9f91cbc9fff24262981 (MD5) %R 10.1051/cocv:2004022 %0 Journal Article %J J. Anal. Math. 94 (2004) 265-291 %D 2004 %T The role of the spectrum of the Laplace operator on \\\\S2 in the H-bubble problem %A Roberta Musina %B J. Anal. Math. 94 (2004) 265-291 %I Hebrew University Magnes Press %G en_US %U http://hdl.handle.net/1963/2894 %1 1806 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-11T08:25:18Z\\nNo. of bitstreams: 1\\n30-03.pdf: 329914 bytes, checksum: 3895c2d75f9be226052e7d4797d7cd9c (MD5) %R 10.1007/BF02789050 %0 Journal Article %J Ann. Henri Poincare 5 (2004) 773-808 %D 2004 %T Rotating Singular Perturbations of the Laplacian %A Michele Correggi %A Gianfausto Dell'Antonio %X We study a system of a quantum particle interacting with a singular time-dependent uniformly rotating potential in 2 and 3 dimensions: in particular we consider an interaction with support on a point (rotating point interaction) and on a set of codimension 1 (rotating blade). We prove the existence of the Hamiltonians of such systems as suitable self-adjoint operators and we give an explicit expression for their unitary semigroups. Moreover we analyze the asymptotic limit of large angular velocity and we prove strong convergence of the time-dependent propagator to some one-parameter unitary group as (\\\\omega \\\\to \\\\infty). %B Ann. Henri Poincare 5 (2004) 773-808 %I Springer %G en_US %U http://hdl.handle.net/1963/2945 %1 1755 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-15T08:20:31Z\\nNo. of bitstreams: 1\\nmath-ph0307056.pdf: 360658 bytes, checksum: 16a12ce4dfd525b63e0a6e703ef9d7bf (MD5) %R 10.1007/s00023-004-0182-8 %0 Journal Article %J J. Phys. A 37 (2004) 5605-5624 %D 2004 %T Semiclassical analysis of constrained quantum systems %A Gianfausto Dell'Antonio %A Lucattilio Tenuta %X We study the dynamics of a quantum particle in R^(n+m) constrained by a strong potential force to stay within a distance of order hbar (in suitable units) from a smooth n-dimensional submanifold M. We prove that in the semiclassical limit the evolution of the wave function is approximated in norm, up to terms of order hbar^(1/2), by the evolution of a semiclassical wave packet centred on the trajectory of the corresponding classical constrained system. %B J. Phys. A 37 (2004) 5605-5624 %I IOP Publishing %G en_US %U http://hdl.handle.net/1963/2997 %1 1336 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-10-01T08:52:42Z\\nNo. of bitstreams: 1\\n0312034v2.pdf: 270295 bytes, checksum: ade82e7ba05cc6dbf50709fd277e1323 (MD5) %R 10.1088/0305-4470/37/21/007 %0 Journal Article %J Internat. J. Game Theory 32 (2004) 561-593 %D 2004 %T Semi-cooperative strategies for differential games %A Alberto Bressan %A Wen Shen %X The paper is concerned with a non-cooperative differential game for two players. We first consider Nash equilibrium solutions in feedback form. In this case, we show that the Cauchy problem for the value functions is generically ill-posed. Looking at vanishing viscosity approximations, one can construct special solutions in the form of chattering controls, but these also appear to be unstable. In the second part of the paper we propose an alternative \\\"semi-cooperative\\\" pair of strategies for the two players, seeking a Pareto optimum instead of a Nash equilibrium. In this case, we prove that the corresponding Hamiltonian system for the value functions is always weakly hyperbolic. %B Internat. J. Game Theory 32 (2004) 561-593 %I Springer %G en_US %U http://hdl.handle.net/1963/2893 %1 1807 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-11T08:11:56Z\\nNo. of bitstreams: 1\\n069.pdf: 389569 bytes, checksum: 3cea0d9a5adfd0be673a7d69218e238a (MD5) %R 10.1007/s001820400180 %0 Journal Article %J SIAM J. Math. Anal. 36 (2004) 659-677 %D 2004 %T A sharp decay estimate for positive nonlinear waves %A Alberto Bressan %A Tong Yang %X We consider a strictly hyperbolic, genuinely nonlinear system of conservation laws in one space dimension. A sharp decay estimate is proved for the positive waves in an entropy weak solution. The result is stated in terms of a partial ordering among positive measures, using symmetric rearrangements and a comparison with a solution of Burgers\\\' equation with impulsive sources. %B SIAM J. Math. Anal. 36 (2004) 659-677 %I SIAM %G en_US %U http://hdl.handle.net/1963/2916 %1 1784 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-11T13:37:38Z\\nNo. of bitstreams: 1\\nmath.AP0307140.pdf: 167236 bytes, checksum: 9e7a6fecd3de67843ca5c73f13bd841d (MD5) %R 10.1137/S0036141003427774 %0 Journal Article %J Int. Math. Res. Not. 2004, no. 32, 1619-1683 %D 2004 %T Singular Z_N curves, Riemann-Hilbert problem and modular solutions of the Schlesinger equation %A Victor Z. Enolski %A Tamara Grava %X We are solving the classical Riemann-Hilbert problem of rank N>1 on the extended complex plane punctured in 2m+2 points, for NxN quasi-permutation monodromy matrices. Following Korotkin we solve the Riemann-Hilbert problem in terms of the Szego kernel of certain Riemann surfaces branched over the given 2m+2 points. These Riemann surfaces are constructed from a permutation representation of the symmetric group S_N to which the quasi-permutation monodromy representation has been reduced. The permutation representation of our problem generates the cyclic subgroup Z_N. For this reason the corresponding Riemann surfaces of genus N(m-1) have Z_N symmetry. This fact enables us to write the matrix entries of the solution of the NxN Riemann-Hilbert problem as a product of an algebraic function and theta-function quotients. The algebraic function turns out to be related to the Szego kernel with zero characteristics. From the solution of the Riemann- Hilbert problem we automatically obtain a particular solution of the Schlesinger system. The tau-function of the Schlesinger system is computed explicitly. The rank 3 problem with four singular points (0,t,1,\\\\infty) is studied in detail. The corresponding solution of the Riemann-Hilbert problem and the Schlesinger system is given in terms of Jacobi\\\'s theta-function with modulus T=T(t), Im(T)>0. The function T=T(t) is invertible if it belongs to the Siegel upper half space modulo the subgroup \\\\Gamma_0(3) of the modular group. The inverse function t=t(T) generates a solution of a general Halphen system. %B Int. Math. Res. Not. 2004, no. 32, 1619-1683 %G en_US %U http://hdl.handle.net/1963/2540 %1 1579 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-12-21T10:08:03Z\\nNo. of bitstreams: 1\\n0306050v2.pdf: 587970 bytes, checksum: 3d350364af41be2317176944f1d85868 (MD5) %R 10.1155/S1073792804132625 %0 Journal Article %J Indiana Univ. Math. J. 53 (2004) 297-392 %D 2004 %T Singularity perturbed elliptic equations with symmetry: existence of solutions concetrating on spheres, Part II %A Antonio Ambrosetti %A Andrea Malchiodi %A Wei-Ming Ni %B Indiana Univ. Math. J. 53 (2004) 297-392 %I Indiana University Mathematics Journal %G en %U http://hdl.handle.net/1963/1663 %1 2455 %2 Mathematics %3 Functional Analysis and Applications %$ Made available in DSpace on 2004-09-01T13:06:06Z (GMT). No. of bitstreams: 0\\n Previous issue date: 2002 %R 10.1512/iumj.2004.53.2400 %0 Journal Article %J SIAM J. Control Optim. 43 (2004) 194-215 %D 2004 %T Small BV solutions of hyperbolic noncooperative differential games %A Alberto Bressan %A Wen Shen %X The paper is concerned with an n-persons differential game in one space dimension. We state conditions for which the system of Hamilton-Jacobi equations for the value functions is strictly hyperbolic. In the positive case, we show that the weak solution of a corresponding system of conservation laws determines an n-tuple of feedback strategies. These yield a Nash equilibrium solution to the non-cooperative differential game. %B SIAM J. Control Optim. 43 (2004) 194-215 %I SIAM %G en_US %U http://hdl.handle.net/1963/2917 %1 1783 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-11T13:46:04Z\\nNo. of bitstreams: 1\\n021.pdf: 296267 bytes, checksum: 16f3c148f2a00551188fee22ac90f666 (MD5) %R 10.1137/S0363012903425581 %0 Journal Article %J Electron. J. Differential Equations (2004) 94 %D 2004 %T Solitary waves for Maxwell Schrodinger equations %A Giuseppe Maria Coclite %A Vladimir Georgiev %X In this paper we study solitary waves for the coupled system of Schrodinger-Maxwell equations in the three-dimensional space. We prove the existence of a sequence of radial solitary waves for these equations with a fixed L^2 norm. We study the asymptotic behavior and the smoothness of these solutions. We show also that the eigenvalues are negative and the first one is isolated. %B Electron. J. Differential Equations (2004) 94 %I SISSA Library %G en %U http://hdl.handle.net/1963/1582 %1 2536 %2 Mathematics %3 Functional Analysis and Applications %$ Made available in DSpace on 2004-09-01T13:04:52Z (GMT). No. of bitstreams: 1\\nmath.AP0303142.pdf: 326987 bytes, checksum: 37c172f10800ae7a41e5398f6a0a0a0e (MD5)\\n Previous issue date: 2002 %0 Journal Article %J C. R. Acad. Sci. Paris, Ser. I 338 (2004) 775-780 %D 2004 %T Solutions concentrating at curves for some singularly perturbed elliptic problems %A Andrea Malchiodi %B C. R. Acad. Sci. Paris, Ser. I 338 (2004) 775-780 %I Elsevier %G en %U http://hdl.handle.net/1963/4869 %1 4647 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-20T14:23:50Z\\nNo. of bitstreams: 0 %R 10.1016/j.crma.2004.03.023 %0 Journal Article %J Bollettino dell\\\'Unione Matematica Italiana Serie 8 7-B (2004), p. 647-661 %D 2004 %T Soluzioni periodiche di PDEs Hamiltoniane %A Massimiliano Berti %B Bollettino dell\\\'Unione Matematica Italiana Serie 8 7-B (2004), p. 647-661 %I Unione Matematica Italiana %G en %U http://hdl.handle.net/1963/4582 %1 4351 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-10-07T10:33:48Z\\nNo. of bitstreams: 1\\nberti2004.pdf: 249023 bytes, checksum: bab6b2d956c1de46de694dfca3bc4cec (MD5) %0 Journal Article %J Rend. Mat. Acc. Lincei, s. 9, v. 15 (2004) 3-4, pp. 225 - 233 %D 2004 %T Some remarks on multidimensional systems of conservation laws %A Alberto Bressan %X This note is concerned with the Cauchy problem for hyperbolic systems of conservation\\nlaws in several space dimensions. We first discuss an example of ill-posedness, for a special system\\nhaving a radial symmetry property. Some conjectures are formulated, on the compactness of the set of\\nflow maps generated by vector fields with bounded variation. %B Rend. Mat. Acc. Lincei, s. 9, v. 15 (2004) 3-4, pp. 225 - 233 %I Accademia Nazionale dei Lincei %G en_US %U http://hdl.handle.net/1963/3642 %1 662 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2009-05-21T10:01:16Z\\nNo. of bitstreams: 1\\nM2004-34-21.pdf: 187400 bytes, checksum: 045bd5d68458b90865a3a4c132a90163 (MD5) %0 Journal Article %J ESAIM COCV 10 (2004) 168-200 %D 2004 %T Stability rates for patchy vector fields %A Fabio Ancona %A Alberto Bressan %X This paper is concerned with the stability of the set of trajectories of a patchy vector field, in the presence of impulsive perturbations. Patchy vector fields are discontinuous, piecewise smooth vector fields that were introduced in Ancona and Bressan (1999) to study feedback stabilization problems. For patchy vector fields in the plane, with polygonal patches in generic position, we show that the distance between a perturbed trajectory and an unperturbed one is of the same order of magnitude as the impulsive forcing term. %B ESAIM COCV 10 (2004) 168-200 %I EDP Sciences %G en_US %U http://hdl.handle.net/1963/2959 %1 1741 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-22T08:49:39Z\\nNo. of bitstreams: 1\\n0111109v1.pdf: 336899 bytes, checksum: 851fc204f3e9f254b9122e0bd1f8894f (MD5) %R 10.1051/cocv:2004003 %0 Journal Article %J Nucl. Phys. B 678 (2004) 638-655 %D 2004 %T Superlocalization formulas and supersymmetric Yang-Mills theories %A Ugo Bruzzo %A Francesco Fucito %X By using supermanifold techniques we prove a generalization of the localization formula in equivariant cohomology which is suitable for studying supersymmetric Yang-Mills theories in terms of ADHM data. With these techniques one can compute the reduced partition functions of topological super Yang-Mills theory with 4, 8 or 16 supercharges. More generally, the superlocalization formula can be applied to any topological field theory in any number of dimensions. %B Nucl. Phys. B 678 (2004) 638-655 %I Elsevier %G en_US %U http://hdl.handle.net/1963/2886 %1 1814 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-10T10:17:55Z\\nNo. of bitstreams: 1\\n0310036v1.pdf: 236322 bytes, checksum: 97623018f9c2507ac14381b6a288c53d (MD5) %R 10.1016/j.nuclphysb.2003.11.033 %0 Journal Article %J Phys. Rev. A 69 (2004) 012311 %D 2004 %T Tensor of coherences parametrization of multiqubit density operators for entanglement characterization %A Claudio Altafini %X For multiqubit densities, the tensor of coherences (or Stokes tensor) is a real parameterization obtained by the juxtaposition of the affine Bloch vectors of each qubit. While it maintains the tensorial structure of the underlying space, it highlights the pattern of correlations, both classical and quantum, between the subsystems and, due to the affine parameterization, it contains in its components all reduced densities of all orders. The main purpose of our use of this formalism is to deal with entanglement. For example, the detection of bipartite entanglement is straightforward, as it is the synthesis of densities having positive partial transposes between desired qubits. In addition, finding explicit mixtures for families of separable states becomes a feasible issue for few qubit symmetric densities (we compute it for Werner states) and, more important, it provides some insight on the possible origin of entanglement for such densities. %B Phys. Rev. A 69 (2004) 012311 %I American Physical Society %G en_US %U http://hdl.handle.net/1963/2845 %1 1855 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-05T11:46:53Z\\nNo. of bitstreams: 1\\n0308019v1.pdf: 274876 bytes, checksum: 4f994250adf7a774cb709fad174c528e (MD5) %R 10.1103/PhysRevA.69.012311 %0 Thesis %D 2004 %T Time-dependent singular interactions %A Michele Correggi %K Rotating singular interactions %I SISSA %G en %U http://hdl.handle.net/1963/5310 %1 5135 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2012-01-31T10:36:04Z\\nNo. of bitstreams: 1\\nCorreggi_PhD.pdf: 7625881 bytes, checksum: 2f2f600f7e0b513322732b8a447ef88d (MD5) %0 Journal Article %J Comm. Math.\\nPhys. 250 (2004) 161-193. %D 2004 %T Virasoro Symmetries of the Extended Toda Hierarchy %A Boris Dubrovin %A Zhang Youjin %X We prove that the extended Toda hierarchy of \\\\cite{CDZ} admits nonabelian Lie algebra of infinitesimal symmetries isomorphic to the half of the Virasoro algebra. The generators $L_m$, $m\\\\geq -1$ of the Lie algebra act by linear differential operators onto the tau function of the hierarchy. We also prove that the tau function of a generic solution to the extended Toda hierarchy is annihilated by a combination of the Virasoro operators and the flows of the hierarchy. As an application we show that the validity of the Virasoro constraints for the $CP^1$ Gromov-Witten invariants and their descendents implies that their generating function is the logarithm of a particular tau function of the extended Toda hierarchy. %B Comm. Math.\\nPhys. 250 (2004) 161-193. %G en_US %U http://hdl.handle.net/1963/2544 %1 1575 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-12-21T12:53:52Z\\nNo. of bitstreams: 1\\n0308152v2.pdf: 341202 bytes, checksum: 306b1f696e6ec01c0eabbeeeca895290 (MD5) %R 10.1007/s00220-004-1084-9 %0 Journal Article %J Mem. Amer. Math. Soc. 169 (2004), no. 801, x+170 pp. %D 2004 %T Well-posedness for general 2x2 systems of conservation laws %A Fabio Ancona %A Andrea Marson %B Mem. Amer. Math. Soc. 169 (2004), no. 801, x+170 pp. %I SISSA Library %G en %U http://hdl.handle.net/1963/1241 %1 2702 %2 Mathematics %3 Functional Analysis and Applications %$ Made available in DSpace on 2004-09-01T12:55:11Z (GMT). No. of bitstreams: 0\\n Previous issue date: 1999 %0 Journal Article %J Applied Math.Optim. 48 (2003), no.1, p.39-66 %D 2003 %T Autonomous integral functionals with discontinous nonconvex integrands: Lipschitz regularity of mimimizers, DuBois-Reymond necessary conditions and Hamilton-Jacobi equations %A Gianni Dal Maso %A Helene Frankowska %B Applied Math.Optim. 48 (2003), no.1, p.39-66 %I SISSA Library %G en %U http://hdl.handle.net/1963/1625 %1 2493 %2 Mathematics %3 Functional Analysis and Applications %$ Made available in DSpace on 2004-09-01T13:05:30Z (GMT). No. of bitstreams: 1\\r\\nmath.AP0207230.pdf: 302400 bytes, checksum: e660ec855386e1a29edd2e20f7abc796 (MD5)\\r\\n Previous issue date: 2002 %R 10.1007/s00245-003-0768-4 %0 Journal Article %J Calc. Var. Partial Differential Equations 16 (2003) 299-333 %D 2003 %T The calibration method for the Mumford-Shah functional and free-discontinuity problems %A Giovanni Alberti %A Guy Bouchitte %A Gianni Dal Maso %X We present a minimality criterion for the Mumford-Shah functional, and more generally for non convex variational integrals on SBV which couple a surface and a bulk term. This method provides short and easy proofs for several minimality results. %B Calc. Var. Partial Differential Equations 16 (2003) 299-333 %I Springer %G en_US %U http://hdl.handle.net/1963/3051 %1 1282 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-10-09T15:00:19Z\\nNo. of bitstreams: 1\\n0105013v1.pdf: 428802 bytes, checksum: de75d15134f2a74b36b0d71355e04835 (MD5) %R 10.1007/s005260100152 %0 Thesis %D 2003 %T Control Problems for Systems of Conservation Laws %A Giuseppe Maria Coclite %K Asymptotic Stabilization %I SISSA %G en %U http://hdl.handle.net/1963/5325 %1 5154 %2 Mathematics %3 Functional Analysis and Applications %4 -1 %$ Submitted by Gerardina Cargnelutti (gerry@sissa.it) on 2012-02-01T11:55:57Z\\nNo. of bitstreams: 1\\nPhD_Coclite_Giuseppe_Maria.pdf: 6164510 bytes, checksum: 461d3d4a88e73be06d19b21a85ab149a (MD5) %0 Journal Article %J J. Math. Phys. 44 (2003) 2357-2372 %D 2003 %T Controllability properties for finite dimensional quantum Markovian master equations %A Claudio Altafini %X Various notions from geometric control theory are used to characterize the behavior of the Markovian master equation for N-level quantum mechanical systems driven by unitary control and to describe the structure of the sets of reachable states. It is shown that the system can be accessible but neither small-time controllable nor controllable in finite time. In particular, if the generators of quantum dynamical semigroups are unital, then the reachable sets admit easy characterizations as they monotonically grow in time. The two level case is treated in detail. %B J. Math. Phys. 44 (2003) 2357-2372 %I American Institute of Physics %G en_US %U http://hdl.handle.net/1963/2909 %1 1791 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-09-11T12:05:33Z\\nNo. of bitstreams: 1\\nquant-ph0211194.pdf: 250415 bytes, checksum: e28216a9c4ccbc9174b725f864ec205a (MD5) %R 10.1063/1.1571221 %0 Journal Article %J J. Math. Pures Appl. 82 (2003) 613-664 %D 2003 %T Drift in phase space: a new variational mechanism with optimal diffusion time %A Massimiliano Berti %A Luca Biasco %A Philippe Bolle %X We consider non-isochronous, nearly integrable, a-priori unstable Hamiltonian systems with a (trigonometric polynomial) $O(\\\\mu)$-perturbation which does not preserve the unperturbed tori. We prove the existence of Arnold diffusion with diffusion time $ T_d = O((1/ \\\\mu) \\\\log (1/ \\\\mu))$ by a variational method which does not require the existence of ``transition chains of tori\\\'\\\' provided by KAM theory. We also prove that our estimate of the diffusion time $T_d $ is optimal as a consequence of a general stability result derived from classical perturbation theory. %B J. Math. Pures Appl. 82 (2003) 613-664 %I Elsevier %G en_US %U http://hdl.handle.net/1963/3020 %1 1313 %2 Mathematics %3 Functional Analysis and Applications %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2008-10-02T15:07:59Z\\nNo. of bitstreams: 1\\n0205307v1.pdf: 505505 bytes, checksum: 2dab01ff574df56912b2fe8d3c56108a