Topology & Geometric Group Theory Seminar

Spring 2008

1:30 - 2:30, Malott 207

Tuesday, February 12

José Burillo, Universitat Politécnica de Catalunya

Commensurators and finite-index subgroups of Thompson's group F

In this talk we will give a complete description of the abstract commensurator of Thompson's group F, and we will prove that it embeds in the quasi-isometry group of F, hence providing a large number of examples of quasi-isometries of F. As a corollary of this result, we classify all finite-index subgroups of F, proving that they are all virtually F, and identifying exactly those which are isomorphic to F itself. (Joint work with Sean Cleary and Claas Röver).

Back to seminar home page.