中科院数学与系统科学研究院
数学研究所
数论研讨班
报告人: Shuji Saito(University of Tokyo)
题 目:A motivic construction of ramification filtrations
时 间:2018.11.14(星期三),17:00-18:00
地 点:数学院南楼N913室(视频)
摘 要: We give a new interpretation of Artin conductors of characters in the framework of theory of motives with modulus. It gives a unified way to understand Artin conductors of characters and irregularities of line bundle with integrable connections as well as overconvergent F-isocrystals of rank 1. It also gives rise to new conductors, for example, for G-torsors with G a finite flat group scheme, which specializes to the classical Artin conductor in case G = Z/nZ. We also give a motivic proof of a theorem of Kato and Matsuda on the determination of Artin conductors along divisors on smooth schemes by its restrictions to curves. Its proof is based on a motivic version of a theorem of Gabber-Katz. This is a joint work with Kay Rulling.