学术报告
Gauss-Bonnet-Chern theorem for singular schemes and Donaldson-Thomas theory-蒋云峰教授（University of Kansas）
题目：Gauss-Bonnet-Chern theorem for singular schemes and Donaldson-Thomas theory
报告人：蒋云峰教授（University of Kansas）
Abstract：
McPherson's index theorem, which is a generalization of the Gauss-Bonnet-Chern theorem to singular varieties, states that the integration of the top Chern-Mather class or Chern-Schwartz MacPherson class of a constructible function $/nu$ on a proper singular variety $X$ is the weighted Euler characteristic of $X$ weighted by $/nu$. The construction and proof use the notion of local Euler obstructions introduced by MacPherson.
The MacPherson's index theorem has been proved to have deep connections to Donaldson-Thomas theory, which is a curve counting theory via moduli space of stable coherent sheaves on smooth Calabi-Yau threefolds. In this talk I will talk about how MacPherson's local Euler obstruction goes into the construction of Donaldson-Thomas invariants, which shows that the Donaldson-Thomas invariants are weighted Euler characteristic, hence are motivic invariants.
时间： 6月12日（周一）上午10:00-11:00
地点：首都师范大学本部教二楼613教室
欢迎全体师生积极参加！
