报告简介：
   

The Gauss-Bonnet-Chern theorem states that for a smooth compact complex manifold X, the integration of the top Chern class of X over X is the topological Euler characteristic of X. In order to study Chern class for singular varieties or schemes, R. MacPherson introduced the notion of local Euler obstruction of singular varieties. The local Euler obstruction is an integer value constructible function on X, and the constant function 1_X can be written down as the linear combination of local Euler obstructions. A characteristic class for a local Euler obstruction was defined by using Nash blow-ups, and is called the Chern-Mather class or Chern-Schwartz-MacPherson class. The Chern-Schwartz-MacPherson class of the constant function 1_X is defined as the Chern class for X.

报告人简介：

蒋云峰， 美国堪萨斯大学， 数学系副教授。  研究方向： 代数几何，枚举几何，数学物理。 代表性论文发表在： 《Journal of Differential Geometry》， 《Journal of Algebraic Geometry》，《C re l le' s Journal》等著名数学杂志上。