Séminaire Gaston Darboux :

Le 09 septembre 2022 à 11:15 - salle 430

Présentée par Uludağ Muhammed -

Mapping class groupoids and Thompson's groups

We concoct a uniform treatment of mapping class groups with Thompson’s groups and to generalize them. We give a description of the outer automorphism group of free groups as the isotropy group of a groupoid, akin to the mapping class groupoid of Penner. We also illustrate some arithmetic aspects of these groupoids