Seminar on Donaldson-Thomas Theory - Mon Nov 27, 9.30, room 136 Sissa

[Andrea Maiorana]

Next Monday (Nov 27, at 9.30 in room 136) we will have the fifth seminar 
of the series:

Title: Virtual classes, symmetric obstruction theories, and Behrend 
function
Speaker: Barbara Fantechi
Abstract: After a brief review of the definition of obstruction theory 
and of the construction of virtual classes, we will define symmetric 
obstruction theories and show that moduli of sheaves on a Calabi-Yau 
3-fold naturally carry such an obstruction theory. We will then define 
constructible functions and their integral, and state without proof 
Behrend’s theorem relating virtual degrees associated to a symmetric 
obstruction theory and integral of the Behrend function. If time allows, 
we will discuss the relationship between symmetric obstruction theories 
and shifted symplectic structures.