Talk page

Title:
Studying the decomposition theorem over the integers

Speaker:
Geordie Williamson

Abstract:
The decomposition theorem is a fundamental result about the topology of algebraic maps. A few years ago De Cataldo and Migliorini gave a Hodge theoretic proof of the decomposition theorem, and reading their proof carefully allows one to give geometric conditions to "decide" when it is true over the integers. The question as to when the decomposition theorem holds over the integers is a question about torsion in cohomology, and is the key to several difficult questions in modular representation theory. I will describe a recent theorem which uses this approach to show that the torsion in the intersection cohomology of Schubert varieties in the general linear group grows exponentially in the rank of the group.

Link:
http://scgp.stonybrook.edu/video_portal/video.php?id=2423

Workshop:
Simons- Program: Geometric representation theory