Michel Brion, January–February, 2026

Professor Michel Brion, Institut Fourier, Université Grenoble Alpes, France will deliver 6 lectures on Actions of finite group schemes. The details are given below.

Venue: Seminar Hall, CMI

Schedule :

• Lectures 1 and 2 will be on January 16 at 3:30 pm. Both talks will be 45 minutes long, with a short break.

• Lectures 3 and 4 will be on January 27 and 29 at 3:30 pm, 1 hour each.

• Lectures 5 and 6 will be on February 2 and 3 at 3:30 pm, 1 hour each.

Actions of finite group schemes

Abstract: Finite group schemes play an important role in the structure and actions of algebraic groups over a field of positive characteristics. The talks will first present general results on finite group schemes, their (rational) actions and their fields of invariants. Then they will focus on equivariant versions of the classical notions of normality and regularity, which remedy the failure of equivariant desingularization in the setting of actions of infinitesimal group schemes. Equivariantly normal curves will be considered in detail, with versions of the Hurwitz and Chevalley-Weil formulas in the above setting.

The lectures will be held in hybrid mode. For the meeting link, please write to enquiry@cmi.ac.in.