The relation between birational geometry and C*-actions

30 March 2023
Start time 
4:00 pm
PovoZero - Via Sommarive 14, Povo (Trento)
Seminar Room “1” (Department of Mathematics)
Target audience: 
University community
Online – Registration required
Registration email: 
Contact person: 
Nicola Fraccarolo

“Doc in Progress” is pleased to introduce you to:

  • Lorenzo Barban - PhD in Mathematics - University of Trento

In this friendly talk we explain how birational transformations arise naturally in the context of C*-actions on projective varieties. With the help of examples, we first review basic notions about algebraic torus actions, explaining for instance the Bialynicki-Birula decomposition. We then concentrate on the geometric quotients of a C*-action, explaining how they are all birational to each other. We conclude by asking the opposite question: under which conditions two birationally equivalent varieties can be realized as geometric quotients by a C*-action?