Dr. Alexander Zakharov, Universität Bilbao: "Commensurability of some right-angled Artin groups"
We give a classification of right-angled Artin groups (RAAGs) defined by trees of diameter 4 up to commensurability. In particular, we prove a conjecture of Behrstock and W.Neumann that there are infinitely many commensurability classes. Since all RAAGs defined by trees of diameter more than 2 are quasi-isometric by a result of Behrstock and W.Neumann, this also gives first examples of RAAGs that are quasi-isometric but not commensurable. This is joint work with I.Kazachkov and M.Casals-Ruiz.
Einladender: R. Weidmann