College of Liberal Arts & Sciences

# Operator Theory Seminar

Speaker:

Bin Sun, Oxford University

Topic:

L2-Betti numbers of fiber bundles

**Abstract:**

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

Location:

VAN 309 or Online (See URL)

Calendar Category:

Seminar

Seminar Category:

Operator Theory