Title: étale duality for p-torsion sheaves on semistable schemes

Speaker: Yigeng Zhao (Universit？t Regensburg)

Abstract: In this talk, we will introduce the relative logarithmic de Rham-Witt sheaves on a semistable scheme X over a local ring of positive characteristic p, and study duality theorems. As an application, we will define a filtration on the abelianized étale fundamental group of open complement of a simple normal crossing divisor on X. In a special case, this filtration coincides with higher ramification groups in local class field theory.