Algebraic Geometry Seminar
Christian Schnell
Stony Brook University
Group actions and freeness
Abstract: My talk is about group actions on projective varieties.
Every algebraic group G over the complex numbers is an extension of an
abelian variety A by a linear algebraic group L (Chevalley's theorem).
The main result is that if G acts algebraically on a projective
variety X, then the cohomology of X is "free" over the cohomology of
A. The precise statement involves Hopf algebras and comodules. This is
joint work with Mark de Cataldo and Yoonjoo Kim.
Wednesday March 18, 2026 at 3:00 PM in 712 SEO