Orateur
Tim De Laat
(University of Münster)
Description
Super-expanders are sequences of finite, d-regular graphs that
satisfy some nonlinear form of spectral gap with respect to all
uniformly convex Banach spaces. This notion vastly strengthens the
classical notion of expander. In this talk I will explain some recent
constructions of super-expanders, coming from actions of higher rank
lattices on Banach spaces and on manifolds. I will also review some
recent constructions of (usual) expanders, for which we do not know
whether they are super-expanders.
