题   目:   Characteristic class and the epsilon factor of a constructible \'etale sheaf

报告人： 阳恩林   博士   （德国Regensburg大学）

摘   要:  In this talk, we will firstly recall the definitions and the properties of singular support and characteristic cycle of a constructible \'etale sheaf on a smooth variety. The singular support, defined by Beilinson, is a closed conical subset of the cotangent bundle.The characteristic cycle, constructed by Saito, is a $\mathbb Z$-linear combination of irreducible components of the singular support.This theory is an algebraic analogue of that studied by Kashiwara and Schapira in a transcendental setting.

In the second part of this talk we will focus on the  joint work with Umezaki.We prove a conjecture of Kato-Saito on a twist formula for the epsilon factor of a constructible \'etale sheaf on a projective smooth variety over a finite field.  In our proof, Beilinson and Saito's theory plays an essential role.

时    间：4月2日 下午7:00

地    点：西大楼308报告厅

邀请人： 秦厚荣   老师