Academy of Mathematics and Systems Science, CAS Colloquia & Seminars
Speaker:
Shuji Saito，University of Tokyo
Inviter:
Title:
A motivic construction of ramification filtrations
Time & Venue:
2018.11.14 17:00-18:00 N913
Abstract:
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.