Amenable open covers

27.05.2026, 10:15  –  2.09.1.22
Forschungsseminar: Gruppen und Operatoralgebren

Kevin Li (FU Berlin)

We want to cover a topological space by open subsets with amenable fundamental group. The minimal number of sets needed is called the "amenable category". Obstructions (lower bounds) are given by L²-Betti numbers and bounded cohomology. I will present computations for right-angled Artin groups and combination theorems for group actions.