Title：Ramification of étale sheaves on positive characteristic varieties 

Speaker：Haoyu Hu （南京大学）

Time：2018年12月21日（周五）    下午  16:00-17:30

Room：东区管理科研楼   数学科学学院1418室

Abstract： The ramification theory is an branch of algebraic number theory very close to the class field theory. Classically, we know the ramification phenomena well on schemes of "dimension 1". In this talk, I will introduce Abbes and Saito's ramification theory for local fields of imperfect residue fields and the theory of singular support and characteristic cycles of étale sheaves on higher dimensional smooth varieties due to Beilinson and Saito. After that, I focus on a recent joint work with J.-B. Teyssier that applies these theories to a boundedness property of nearby cycles and étale cohomology groups.