Kummer-Artin-Schreier-Witt Theory

Fuente: arXiv
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Main Authors: Dang, Huy, Nguyen-Dang, Khai-Hoan
Format: Preprint
Published: 2024
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author Dang, Huy
Nguyen-Dang, Khai-Hoan
author_facet Dang, Huy
Nguyen-Dang, Khai-Hoan
contents We study the problem of lifting the Artin--Schreier--Witt isogeny from characteristic $p>0$ to characteristic $0$, which is central to the lifting problem for Galois covers of algebraic schemes in positive characteristic. We introduce a new technique that associates a Kummer class, representing a tamely ramified cyclic extension, to a Witt vector via Matsuda's Kummer--Artin--Schreier--Witt theory. This viewpoint leads to an explicit construction of a lift of the isogeny over a concrete base ring. Our results lay the groundwork for further applications, including the study of inseparable extensions and Kato's refined Swan conductor.
format Preprint
id arxiv_https___arxiv_org_abs_2410_21224
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Kummer-Artin-Schreier-Witt Theory
Dang, Huy
Nguyen-Dang, Khai-Hoan
Number Theory
Algebraic Geometry
We study the problem of lifting the Artin--Schreier--Witt isogeny from characteristic $p>0$ to characteristic $0$, which is central to the lifting problem for Galois covers of algebraic schemes in positive characteristic. We introduce a new technique that associates a Kummer class, representing a tamely ramified cyclic extension, to a Witt vector via Matsuda's Kummer--Artin--Schreier--Witt theory. This viewpoint leads to an explicit construction of a lift of the isogeny over a concrete base ring. Our results lay the groundwork for further applications, including the study of inseparable extensions and Kato's refined Swan conductor.
title Kummer-Artin-Schreier-Witt Theory
topic Number Theory
Algebraic Geometry
url https://arxiv.org/abs/2410.21224