Quasi-morphisms on Surface Diffeomorphism groups

Series
Geometry Topology Seminar
Time
Monday, March 28, 2022 - 2:00pm for 1 hour (actually 50 minutes)
Location
Speaker
Jonathan Bowdenjonathan.bowden@mathematik.uni-regensburg.de
Organizer
Roberta Shapiro

We discuss the problem of constructing quasi-morphisms on the group of diffeomorphisms of a surface that are isotopic to the identity, thereby resolving a problem of Burago-Ivanov-Polterovich from the mid 2000’s. This is achieved by considering a new kind of curve graph, in analogy to the classical curve graph first studied by Harvey in the 70’s, on which the full diffeomorphism group acts isometrically. Joint work with S. Hensel and R. Webb.