Texas A&M University, Department of Mathematics, 216 Milner Hall, 24th of October 2007, 2:00-2:50

Groups and Dynamics Seminar


Gromov hyperbolic homogeneous Riemannian manifolds

Romain Tessera of Vanderbilt University

We will explain two proofs of the fact (which is a new result) that a homogeneous manifold is Gromov hyperbolic if and only if it is  quasi-isometric to a semi-direct product of a nilpotent Lie group N with R, where the action of R+ is contractant on N. One proof uses  Lp-cohomology, and the other one uses Dehn functions and asymptotic cones.