Polarizations and torsors of abelian varieties
- đ¤ Speaker: Jef Laga, Cambridge/St John's College đ Website
- đ Date & Time: Wednesday 29 October 2025, 14:15 - 15:15
- đ Venue: CMS MR13
Abstract
Polarizations on abelian varieties are a central part of their theory, for example when constructing moduli spaces. Over an algebraically closed field, every polarization is represented by an ample line bundle on A, but this need not be true in general. To remedy this, Poonen and Stoll have asked: can every polarization be represented by a line bundle on some torsor under A? This question also arises naturally from the work of Alexeev on compactifying moduli of abelian varieties. In this talk, we will explain why the answer to this question is often yes and sometimes no. Along the way, we will encounter Mumford theta groups, negligible group cohomology and twisted cohomology of moduli spaces of abelian varieties.
Series This talk is part of the Algebraic Geometry Seminar series.
Included in Lists
- Algebraic Geometry Seminar
- All CMS events
- All Talks (aka the CURE list)
- bld31
- CMS Events
- CMS MR13
- DPMMS info aggregator
- DPMMS lists
- DPMMS Lists
- DPMMS Pure Maths Seminar
- Hanchen DaDaDash
- Interested Talks
- School of Physical Sciences
Note: Ex-directory lists are not shown.
![[Talks.cam]](/static/images/talkslogosmall.gif)



Wednesday 29 October 2025, 14:15-15:15