NORTHEASTERN UNIVERSITY
MATHEMATICS DEPARTMENT
 
Geometry-Algebra-Singularities-Combinatorics 
Seminar
 
 
The Decomposition Theorem: Hilbert schemes and Heisenberg algebras 
 
 

Mark DeCataldo

(Harvard University)
 
 

Northeastern University

509 Lake Hall

12:00 p.m., Tuesday, February 9, 1999

 
 
 
Abstract:  Given a complex algebraic surface X, the associated Hilbert scheme is a collection of projective varieties which parameterizes the subvarieties of X. The rational cohomology groups of the Hilbert scheme are naturally the standard representation of a certain infinite dimensional graded Lie algebra, called the Heisenberg/Clifford algebra. In the hyperkähler case the character formulas of these representations are modular forms.

The cohomology groups mentioned above, though transcendental in nature have been computed using the purely algebraic method of reduction to finite fields (Weil Conjectures).

In joint work with L. Migliorini we give a new, simpler and geometric method, suggested by the presence in the picture of the Heisenberg algebra, to calculate these cohomology groups. In particular, the method works for not necessarily algebraic surfaces.  

 
Geometry-Algebra-Singularities-Combinatorics home page:
http://www.math.neu.edu/~suciu/GASC.html

 
Web page:  Alexandru I. Suciu  Created: Jan. 26, 1999    Updated: Feb. 1, 1999 
Comments to:  alexsuciu@neu.edu URL: http://www.math.neu.edu/~suciu/gas/decataldo.html