"Geometry and Analysis on Groups" Research Seminar

Time: 2015.03.17, 15:00--17:00
Location: Seminarraum 8, Oskar-Morgenstern-Platz 1, 2.Stock
Title: "Separation and Expanders."
Speaker: David Hume (Université Catholique de Louvain)
Abstract: We introduce a graph invariant called the separation profile and prove that it detects whether a given graph admits uniformly expanding subgraphs. Using this we prove that there are a continuum of non-coarsely equivalent expander families and a continuum of quasi-isometry classes of finitely generated groups which coarsely contain expanders.