Operator Theory Seminar

Bin Sun, Oxford University
L2-Betti numbers of fiber bundles


We study the L²-Betti numbers of fiber bundles F → E →  B of manifolds.  Under certain conditions (e.g., when F is simply connected), b﹡(2)(E) can be computed using the twisted L²-Betti numbers of B. We relate the twisted and untwisted L²-Betti numbers of B when π1(B) is locally indicable. As an application, we compute b﹡(2)(E) when B is either a surface or a non-positively curved 3-manifold. This is a joint work with Dawid Kielak.

Event Date: 
September 27, 2022 - 1:30pm to 2:20pm
VAN 309 or Online (See URL)
Calendar Category: 
Seminar Category: 
Operator Theory