Back to Algebraic Geometry Seminar: Fall 2015
Algebraic Geometry Seminar
Date: Tuesday, Dec 1, 2015
Time: 3:30PM - 4:30PM
Location: JFB 102
Daniel Litt
Columbia University
Title |
Non-Abelian Lefschetz Hyperplane Theorems |
Abstract |
How are the properties of a variety X related to those of an ample divisor D in X? Classical Lefschetz hyperplane theorems answer this question by comparing the cohomology or homotopy type of X to that of D. I’ll describe new results, encapsulating some of these older Lefschetz theorems, which compare F(X) to F(D) where F is any functor which is representable in a suitable sense. For example, F can be \pi_1, or a moduli functor. While the main results are in characteristic zero, the method of proof passes through positive characteristic. |
Algebraic Geometry