algebra/topology seminar

Speaker: Damian Osajda (University of Wroclaw and Polish Academy of Sciences)

Title: Coarsely aspherical groups

Abstract: Free groups and groups acting geometrically on nonpositively
curved 2-complexes are examples of groups that do not "contain
asymptotically" essential spheres. It is an interesting phenomenon that
groups with similar features exist in higher dimensions. Examples
are systolic groups. I will define various notions of such coarse
asphericity and show several interesting properties of corresponding groups.
In particular, I will present restrictions on normal subgroups.
I will talk about some open problems related to the subject.
Among them there is a question of Gromov-Bestvina-Mosher-Sageev
about highly dimensional groups not containing Poincare duality
groups of dimension above two.