String topology and the cohomology of finite groups of Lie type

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Jesper Grodal, University of Copenhagen

Online Talk 

Finite groups of Lie type, such as SL_n(F_q), Sp_n(F_q)..., are ubiquitous in mathematics, and calculating their cohomology has been a central theme over the years. It has calculationally been observed that (when calculable) their mod ell cohomology agree with the mod ell cohomology of LBG(C), the free loop space on BG(C), the classifying space of the corresponding complex algebraic group G(C), as long as q is congruent to 1 mod ell.

It turns out that this “coincidence” has root in an underlying structural relationship, that combines string topology à la Chas–Sullivan and the theory p-compact groups, and provides much more general statements. In my talk I'll give a tour of this circle of ideas. Joint work with Anssi Lahtinen.