%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