Title: Donaldson-Thomas Type Invariants via Microlocal Geometry
Speaker: Professor Kai Behrend
Speaker Info: UBC
Brief Description:
Special Note:
Abstract:
We prove that Donaldson-Thomas type invariants (such as holomorphic Casson invariants) are equal to weighted Euler characteristics of their moduli spaces. In particular, such invariants depend only on the scheme structure of the moduli space, not the symmetric obstruction theory used to define them. We also introduce new invariants generalizing Donaldson-Thomas type invariants to moduli problems with open moduli space. These are useful for computing Donaldson-Thomas type invariants over stratifications. We will discuss an application to the Hilbert scheme of points on a Calabi-Yau threefold.Date: Thursday, August 02, 2007