Speaker: Kestutis Cesnavicius (U. Paris Sud)
Time: 15h15, Friday, April 2, 2021
Join Zoom Meeting:
ZOOM ID：466 356 2952
Password：mcm1234
https://zoom.com.cn/j/4663562952?pwd=MytDVU9tUlg5LzFHNHRHZmFMZ0JaUT09
Session Chair: Prof. Phung Ho Hai (VAST Hanoi)
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 quasi-split and R is unramified. To overcome obstacles that have so far kept the mixed characteristic case out of reach, we adapt Artin's construction of "good neighborhoods" to the setting where the base is a discrete valuation ring, build equivariant compactifications of tori over higher dimensional bases, and study the geometry of the affine Grassmannian in bad characteristics.
For general information of the AGEA seminar, please check out
https://sites.google.com/ncts.ntu.edu.tw/agea-seminar
or the mirror site
http://www.math.ntu.edu.tw/~jkchen/agea-seminar.html | 
