Introduction to Gerbs

by Drimik Roy Chowdhury (IMJ-PRG, Sorbonne Université)

Wednesday Mar 18, 2026, 3:30 PM → 4:45 PM Europe/Paris

Salle Pierre Grisvard (IHP - Bâtiment Borel)

We introduce the notion of gerbes — a higher categorical analogue of torsors. We discuss their many incarnations coming from various formalisms (e.g., Azumaya algebras and Brauer groups, Tannakian categories) and then study in detail Nori’s fundamental group scheme and its generalization as a gerbe.