Andreas Thom (U. Leipzig): Entropy, Determinants, and L2-Torsion

Abstract: 
This talk is about the entropy of group actions of amenable groups. 
I will present recent progress on questions asked by Christopher
Deninger about the entropy of certain principal algebraic dynamical
systems. I will show that the entropy of an algebraic dynamical system
agrees with the L2-torsion of the dual module over the integral group ring
of the group acting. As a by-product we prove vanishing of the L2-torsion
of amenable groups, which was conjectured by Wolfgang Lueck. This is joint
work with Hanfeng Li.