# What is... string topology of finite groups of Lie type?

Anssi Lahtinen will explain what string topology of finite groups of Lie type is.

Abstract: A finite group of Lie type $G(\mathbb F_q)$ is a finite discrete object depending heavily on $q$ while the space of continuous maps from the circle into the classifying space of the corresponding compact Lie group is a big infinite-dimensional space independent of $q$. Quite reasonably, one might expect the mod-$\ell$ cohomology groups of these seemingly disparate mathematical objects to have little relation to each other, yet computations reveal that they often turn out to be isomorphic when $q$ is congruent to 1 mod $\ell$.  In this talk, I will discuss my recent work with Jesper Grodal shedding light on this mysterious phenomenon.

"What is...?" is an accessible and non-technical seminar where speakers explain in one (short) lecture some object or theorem that they think is interesting. There will be drinks and snacks during the talk. See the seminar website for more information.