Tsachik Gelander (Weizmann Institute)

Infinite volume and infinite injectivity radius

We prove the following conjecture of Margulis. Let M=Λ\G/K be a locally symmetric space where G is a simple Lie group of real rank at least 2. If M has infinite volume then it admits injected contractible balls of any radius. This generalizes the celebrated normal subgroup theorem of Margulis to the context of arbitrary discrete subgroups of G and has various other applications. We prove this result by studying random walks on the space of discrete subgroups of G and analysing the possible stationary limits. This is a joint work with Mikolaj Fraczyk.

Schedule

14:00 - Pretalk with Tsachik Gelander and PhD Students

14:30 - Coffee Break

15:00 - RTG colloquium