We strengthen a result of Hankeâ€“Schick about the strong Novikov conjecture for low degree cohomology by showing that their non-vanishing result for the maximal group $C^*$-algebra even holds for the reduced group $C^*$-algebra. To achieve this we provide a Fell absorption principle for certain exotic crossed product functors.

ER - TY - JOUR T1 - The Baumâ€“Connes conjecture localised at the unit element of a discrete group JF - ArXiv e-prints Y1 - 2018 A1 - Paolo Antonini A1 - Azzali, S. A1 - Skandalis, G. KW - 19K35 KW - 46L80 KW - 46L85 KW - 58J22 KW - Mathematics - K-Theory and Homology KW - Mathematics - Operator Algebras ER - TY - JOUR T1 - The injectivity radius of Lie manifolds JF - ArXiv e-prints Y1 - 2017 A1 - Paolo Antonini A1 - Guido De Philippis A1 - Nicola Gigli KW - (58J40) KW - 53C21 KW - Mathematics - Differential Geometry AB -We prove in a direct, geometric way that for any compatible Riemannian metric on a Lie manifold the injectivity radius is positive

UR - https://arxiv.org/pdf/1707.07595.pdf ER - TY - JOUR T1 - Integrable lifts for transitive Lie algebroids JF - ArXiv e-prints Y1 - 2017 A1 - Androulidakis, I. A1 - Paolo Antonini KW - 14F40 KW - 58H05 KW - Mathematics - Differential Geometry AB -Inspired 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.

UR - https://arxiv.org/pdf/1707.04855.pdf ER -