Non-positively curved groups and spaces

This week there was the workshop “Non-positively curved groups and spaces” in Regensburg.

It consisted of 3 lecture series and some more talks.

One lecture series was by Igor Belegradek on topological properties and fundamental groups of nonpositively curved manifolds, another by Alessandro Sisto about acylindrically hyperbolic groups, a quite general class of groups of somehow hyperbolic behaviour, which besides hyperbolic and relatively hyperbolic groups also encompasses mapping class and outer automorphism groups.

The third lecture series was by Jon McCammond about his recent proof (with Michael Dougherty and Stefan Witzel) of the CAT(0)-property for braid groups. The picture below is from his slides and shows a small part of the exhibition of mathematical models at the university of Regensburg. You can see more pictures from the exhibition here

Besides the lecture series there were 10 more talks by participants. The picture below shows Avradimi’s talk about ends of nonpositively curved manifolds with some nice drawings of intersecting horospheres in higher rank symmetric spaces.