** "Geometry and Analysis on Groups" Research Seminar **

**Time:** 2017.01.17, 15:00–17:00

**Location:** Seminarraum 9, Oskar-Morgenstern-Platz 1, 2.Stock

**Title:** "Characterizing a vertex-transitive
graph by a large ball."

**Speaker:** Mikael
de la Salle (ENS de Lyon)

**Abstract:**
The subject of the talk will be vertex-transitive infinite connected graphs with bounded degree and with a property of large scale simple connectedness. The most classical examples of such objects are Cayley graphs of finitely presented groups, but I will explain that there are (uncountably) many other, and I will study some topological questions on the space of all such graphs. In passing we will encounter groups with polynomial growth, lattices in simple Lie groups, Bruhat Tits buildings, close local fields, second cohomology groups... Based on joint works with Romain Tessera.