Speaker: Johannes Anschütz (Bonn)

Date, time & place: December 7, 2017, 4:45 pm, WSC-N-U-3.05

Title: Extending torsors on the punctured spectrum of Ainf

Abstract: In the theory of canonical integral models of Shimura varieties a key construction is the extension of torsors under a parahoric group scheme on the punctured spectrum of the power series ring over a ring of Witt vectors to the whole spectrum as proven by Kisin and Pappas in tamely ramified cases. In this talk I want to discuss results on the same question over Fontaine's ring Ainf. These results imply the one of Kisin and Pappas in full generality as well as the existence of a canonical specialization map from Scholze's B+dR-affine Grassmannian to the Witt vector affine Grassmannian which I want to discuss.