Ulam stability for lamplighters and Thompson groups
Speaker:
Francesco Fournier-Facio, ETH Zürich
Date and Time:
Wednesday, November 30, 2022 - 11:00am to 12:15pm
Location:
Fields Institute, Room 210
Abstract:
Last year, Monod proved the vanishing of the bounded cohomology of many lamplighters, and via coamenability he obtained the same result for many groups acting on the line, such as Thompson's group F. We will see that the techniques involved translate well to asymptotic cohomology, and allow to prove Ulam stability of such groups. Some of the steps of the proof establish more general facts about asymptotic cohomology and stability, most notably we prove a relative version of Kazhdan's Theorem on stability of amenable groups.