Bounded cohomology of diffeomorphism groups (Zixiang Zhou, EPFL)

18.11.2025 10:30

In 2021, Monod introduced a novel approach to prove the bounded acyclicity of abstract groups, which he successfully applied to Thompson's group F. This idea was further developed by N. Monod, S. Nariman, and F.F. Francesco, who combined it with tools from algebraic topology to compute the bounded cohomology of transformation groups of manifolds. A key application of their work is establishing the (un)boundedness of characteristic classes in the corresponding classifying spaces. In this talk I will briefly introduce Monod's observation, and show how to combine tools from algebraic topology, dfferential topology and group theory to compute the bounded cohomology of Diff(M), especially for M=S^n with n>3.

Lieu

Bâtiment: Conseil Général 7-9

Room 1-05, Tuesday 18.11.2025, Séminaire "Groupes et géométrie"

entrée libre