NORTHEASTERN UNIVERSITY
MATHEMATICS DEPARTMENT
 
Geometry-Algebra-Singularities-Combinatorics 
Seminar
 
 
Counterexamples to Torelli, Elliptic Threefolds and Twisted Sheaves 
 
 

Andrei Caldararu

(Cornell University)
 
 

Northeastern University

509 Lake Hall

1:30 p.m., Monday, March 6, 2000

 
 
Abstract: The naive translation of the Torelli theorem from K3 surfaces to Calabi-Yau threefolds does not work, and counterexamples to it are helpful for understanding what the correct statement should be. In the first part of my talk I shall attempt to explain how the question of finding counterexamples to Torelli is related to equivalences of derived categories. Then, I'll atempt to construct such a counterexample using the Ogg-Shafarevich theory for elliptic threefolds. The equivalence of derived categories I construct is best explained through the use of the Jacobian fibration and twisted sheaves. If time will allow I shall attempt to explain why singularities appear and their relationship to the stable singularities in Mirror Symmetry, as well as how this relates to questions from algebra, like derived equivalences for Azumaya algebras and tilting modules. 
 
Home Web page:  Alexandru I. Suciu  Created: February 2, 2000   
Maintained by:  Hal Schenck  URL: http://www.math.neu.edu/~GASC/gas/andreic.html