Title: The characteristic cycle and ramification theory Speaker: 谷田川 友里 (Yuri Yatagawa,埼玉大学) Time: 2019-8-9, 10:00-11:00 Place: N602 Abstract: The characteristic cycle of a constructible sheaf on a smooth variety is defined by T. Saito in 2015 to be an algebraic cycle on the cotangent bundle of the variety. The cycle is known to compute the Euler characteristic of the sheaf and have some relation with the ramification of the sheaf. In this talk, I will introduce a result for a computation of the cycle using ramification theory in case the sheaf is of rank 1 and on a surface. After that, I would like to explain a small recent develop in such a problem in case the sheaf has a specific ramification and is of Artin-Schreier but the variety is of arbitrary dimension. Attachment: