Martin Olsson : Independence of $\ell$ and local terms

Posted by Mihnea Popa , part of the Algebraic Geometry Seminar.

At

April 10, 2013, 4 p.m.

In

SEO 427

Abstract

I will give an overview of recent progress on several related questions on independence of $\ell $ for correspondences acting on $\ell $-adic sheaves. The main focus will be on local terms whose rationality and independence of $\ell $ implies global independence of $\ell $ results using trace formulas. In the case of constant coefficients the calculation of local terms is reduced to intersection theory calculations via the theory of Borel-Moore homology and localized chern classes. I will also discuss various results on independence of $\ell $ for correspondences acting on complexes of sheaves.