Divergence and thickness are well studied quasi-isometry invariants for finitely generated groups. In general, they can be quite difficult to compute. In the case of right-angled Coxeter groups, Levcovitz introduced the notion of hypergraph index, which can be algorithmically computed from the defining graph, and proved that it determines the thickness and divergence of the group. I will talk about joint work with Yusra Naqvi, Ignat Soroko, and Anne Thomas, in which we propose a definition of hypergraph index for general Coxeter groups. We show that it determines the divergence and thickness in an infinite family of non-right-angled Coxeter groups.
Join Zoom meeting ID 613 8691 2732 or via the link below.
Passcode: A group is called an ________ group if it admits an invariant mean. (8 letters, lowercase)