Lück W. and Schick, T.: Various L2-signatures and a topological L2-signature theorem
Abstract:
For a normal covering over a closed oriented topological manifold
we give a proof of the
L2-signature theorem with twisted coefficients,
using Lipschitz structures and the Lipschitz signature operator
introduced by Teleman. We also prove that the L-theory isomorphism
conjecture as well as the C^*_max-version of the
Baum-Connes conjecture imply the L2-signature theorem for
a normal covering over a Poincaré space, provided that the
group of deck transformations is torsion-free.
We discuss the various possible
definitions of L2-signatures (using the signature operator, using
the cap product of differential forms, using a cap product in
cellular L2-cohomology,...) in this situation, and prove that
they all coincide.
Thomas Schick