Geometric Analysis and Topology Seminar

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Rigidity of Warped Cones and Coarse Geometry of Expanders

Speaker: Wouter Van Limbeek, Michigan

Location: Warren Weaver Hall 517

Date: Wednesday, February 7, 2018, 11 a.m.

Synopsis:

Finitely generated subgroups of compact Lie groups give rise to expander graphs via a warped cone construction. We study the dependence of the coarse geometry of such expander graphs on the original subgroup and establish a dynamical analogue of quasi-isometric rigidity theorems in geometric group theory: Namely, the coarse geometry of the warped cone determines the subgroup up to commensurability, unless the group has abelian factors. This is joint work with David Fisher and Thang Nguyen.