Date

Ober­sem­in­ar "Kom­bin­at­or­ische Al­geb­rais­che Geo­met­rie": Sean Mo­n­ahan (TU Mu­nich): Horo­spher­ic­al vari­et­ies and stacks

Location: D2 314
Organizer: Prof. Dr. Martin Ulirsch

Title: Horospherical varieties and stacks

Abstract: To begin, I will introduce horospherical varieties and their known combinatorial theory. Horospherical varieties generalize toric varieties and their correspondence with polyhedral fans: instead of a torus action, we can use any reductive group, and instead of fans, we use a generalization called "coloured" fans. After this, I will highlight some of my research on extending this combinatorial theory to the world of algebraic stacks, namely a correspondence between horospherical stacks and "stacky" coloured fans.