Zhijia Zhang : Equivariant birational geometry of Fano threefolds

Posted by Kevin Tucker , part of the Algebraic Geometry Seminar.

At

Oct. 6, 2025, 3 p.m.

In

636 SEO

Abstract

The notion of G-varieties was introduced by Manin when he studied rationality problems of surfaces. Broadly speaking, a G-variety is a variety X carrying an action of a group G. The group can act via automorphisms of X or via Galois actions if the base field is non-closed. There are close connections, as well as drastic differences between these two types of actions from the perspective of birational geometry. In this talk, I will explore these similarities and differences with a focus on equivariant unirationality of Fano threefolds. This is joint work with Yuri Tschinkel and Ivan Cheltsov.