Virtual talk.
If an oriented closed connected aspherical manifold admits an open amenable cover of ``small'' multiplicity, then the rank gradient, the \(\ell^2\)-Betti numbers and the torsion homology gradients of its fundamental group are all zero. This phenomenon admits a uniform proof via a dynamical version of simplicial volume. In this talk, I will survey this method as well as related results on 3-manifolds. This is based on joint work with Marco Moraschini and Roman Sauer.
Links:
[1] http://www.mpim-bonn.mpg.de/de/taxonomy/term/39
[2] http://www.mpim-bonn.mpg.de/de/node/11255