Gérard Besson (Grenoble) will speak in the geometr seminar at 1.30pm on 18th March (note the unusual time!) in the Salle des Profs (9th floor of building NO). Gérard’s title is “Finiteness Theorems for Gromov-Hyperbolic Groups” and his abstract is below.
This is a joint work with G. Courtois, S. Gallot and A. Sambusetti. We shall prove that, given two positive numbers delta and H, there are finitely non cyclic torsion-free delta-hyperbolic marked groups (Gamma , Sigma) satisfying Ent(Gamma, Sigma) <= H, up to isometry (of marked groups). Here a marked group is a group Gamma together with a symmetric generating set Sigma and Ent is the entropy of the marked group.
The talk is intended to be elementary; the purpose is to define all these notions and give a flavour of the proof