Geometrization of covering groups

Time: 15:45-17:15 11 September 2025

Venue: Room 507, A6, Institute of Mathematics

Online (Zoom meeting): https://us06web.zoom.us/j/88177098362?pwd=qPMMbcRjMYoR321S7oqW3MUbZHKFGa.1

Meeting ID: 881 7709 8362

Passcode: 123456

Abstract: Reductive groups over local fields admit (typically non-algebraic) topological covers, called "covering groups". An old idea of Deligne is that they arise as transgressions of degree-4 étale cohomology classes of the classifying stack. In this talk, I will explain how this old idea can be combined with new methods in arithmetic geometry to make advances in the Langlands program for covering groups.