I will tell about the theory of prismatic cohomology (developed recently by Bhatt and Scholze) and what it gives when applied to the classifying stack of a reductive group. In particular we will discuss the (originally conjectural) Totaro's inequality between the dimensions of de Rham and singular F_p-cohomology of such stacks; if time permits I will also briefly explain how to use prismatic cohomology and the classical Quillen's computation of mod 2 singular cohomology of BSpin(n) to compute the mod 2 de Rham cohomology of the corresponding classifying stack.
Password: as before.
Contact: Aru Ray and Tobias Barthel.
Links:
[1] http://www.mpim-bonn.mpg.de/taxonomy/term/39
[2] http://www.mpim-bonn.mpg.de/TopologySeminar