Algebraic Geometry Seminar Fall 2011
The seminar meets on Fridays at 2:25 pm in Van Vleck B215.
The schedule for the previous semester is here.
Fall 2011
date  speaker  title  host(s) 

Sep. 23  Yifeng Liu (Columbia)  Enhanced Grothendieck's operations and base change theorem for
sheaves on Artin stacks 
Tonghai Yang 
Oct. 7  Zhiwei Yun (MIT)  Cohomology of Hilbert schemes of singular curves  Shamgar Gurevich 
Oct. 14  Javier Fernández de Bobadilla (Instituto de Ciencias Matematicas, Madrid)  Nash problem for surfaces  
Nov. 25  Shamgar Gurevich (Madison)  Canonical Hilbert Space: Why? How? and its Categorification

Title: Enhanced Grothendieck's operations and base change theorem for sheaves on Artin stacks
Abstract: Laszlo and Olsson have conditionally defined Grothendieck's six operations for sheaves on Artin stacks, and proved the base change theorem on the cohomological level. I will explain a new approach toward the theory of sheaves on Artin stacks in very general setups. With this approach, the base change theorem follows in a natural way. Our method relies on the theory of infinity categories developed by Lurie. This is a joint work with Weizhe Zheng.
Spring 2012
date  speaker  title  host(s) 

May 4  Mark Andrea de Cataldo (Stony Brook)  TBA  Maxim 
Abstracts
Yifeng Liu
TBA
Zhiwei Yun
Cohomology of Hilbert schemes of singular curves
Abstract: For a smooth curve, the Hilbert schemes are just symmetric powers of the curve, and their cohomology is easily computed by the H^1 of the curve. This is known as Macdonald's formula. In joint work with Davesh Maulik, we generalize this formula to curves with planar singularities (which was conjectured by L.Migliorini). In the singular case, the compactified Jacobian will play an important role in the formula, and we make use of Ngo's technique in his celebrated proof of the fundamental lemma.