Lifting $G$-Valued Galois Representations when $\ell \neq p$

Fuente: arXiv
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Main Authors: Booher, Jeremy, Cotner, Sean, Tang, Shiang
Format: Preprint
Published: 2022
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author Booher, Jeremy
Cotner, Sean
Tang, Shiang
author_facet Booher, Jeremy
Cotner, Sean
Tang, Shiang
contents In this paper we study the universal lifting spaces of local Galois representations valued in arbitrary reductive group schemes when $\ell \neq p$. In particular, under certain technical conditions applicable to any root datum we construct a canonical smooth component in such spaces, generalizing the minimally ramified deformation condition previously studied for classical groups. Our methods involve extending the notion of isotypic decomposition for a $\textrm{GL}_n$-valued representation to general reductive group schemes. To deal with certain scheme-theoretic issues coming from this notion, we are led to a detailed study of certain families of disconnected reductive groups, which we call weakly reductive group schemes. Our work can be used to produce geometric lifts for global Galois representations, and we illustrate this for $\mathrm{G}_2$-valued representations.
format Preprint
id arxiv_https___arxiv_org_abs_2211_03768
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Lifting $G$-Valued Galois Representations when $\ell \neq p$
Booher, Jeremy
Cotner, Sean
Tang, Shiang
Number Theory
Algebraic Geometry
11F80
In this paper we study the universal lifting spaces of local Galois representations valued in arbitrary reductive group schemes when $\ell \neq p$. In particular, under certain technical conditions applicable to any root datum we construct a canonical smooth component in such spaces, generalizing the minimally ramified deformation condition previously studied for classical groups. Our methods involve extending the notion of isotypic decomposition for a $\textrm{GL}_n$-valued representation to general reductive group schemes. To deal with certain scheme-theoretic issues coming from this notion, we are led to a detailed study of certain families of disconnected reductive groups, which we call weakly reductive group schemes. Our work can be used to produce geometric lifts for global Galois representations, and we illustrate this for $\mathrm{G}_2$-valued representations.
title Lifting $G$-Valued Galois Representations when $\ell \neq p$
topic Number Theory
Algebraic Geometry
11F80
url https://arxiv.org/abs/2211.03768