Time: 9:00 - 11:00, October 7, 2020

Venue: Room 612, A6, Institute of Mathematics

Abstract: The Grothendieck--Serre conjecture predicts that every generically trivial torsor under a reductive group scheme G over a regular local ring R is trivial. We settle it in the case when G is split and R is unramified. To overcome obstacles that have so far kept the mixed characteristic case out of reach, we rely on the recently-established Cohen--Macaulay version of the resolution of singularities.