On endomorphisms of extensions in Tannakian categories

Fuente: arXiv
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Auteur principal: Eskandari, Payman
Format: Preprint
Publié: 2023
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author Eskandari, Payman
author_facet Eskandari, Payman
contents We prove some analogues of Schur's lemma for endomorphisms of extensions in Tannakian categories. More precisely, let $\mathbf{T}$ be a neutral Tannakian category over a field of characteristic zero. Let $E$ be an extension of $A$ by $B$ in $\mathbf{T}$. We consider conditions under which every endomorphism of $E$ that stabilizes $B$ induces a scalar map on $A\oplus B$. We give a result in this direction in the general setting of arbitrary $\mathbf{T}$ and $E$, and then a stronger result when $\mathbf{T}$ is filtered and the associated graded objects to $A$ and $B$ satisfy some conditions. We also discuss the sharpness of the results.
format Preprint
id arxiv_https___arxiv_org_abs_2306_06817
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle On endomorphisms of extensions in Tannakian categories
Eskandari, Payman
Algebraic Geometry
Number Theory
Representation Theory
18M25 (primary), 08A35, 14F42 (secondary)
We prove some analogues of Schur's lemma for endomorphisms of extensions in Tannakian categories. More precisely, let $\mathbf{T}$ be a neutral Tannakian category over a field of characteristic zero. Let $E$ be an extension of $A$ by $B$ in $\mathbf{T}$. We consider conditions under which every endomorphism of $E$ that stabilizes $B$ induces a scalar map on $A\oplus B$. We give a result in this direction in the general setting of arbitrary $\mathbf{T}$ and $E$, and then a stronger result when $\mathbf{T}$ is filtered and the associated graded objects to $A$ and $B$ satisfy some conditions. We also discuss the sharpness of the results.
title On endomorphisms of extensions in Tannakian categories
topic Algebraic Geometry
Number Theory
Representation Theory
18M25 (primary), 08A35, 14F42 (secondary)
url https://arxiv.org/abs/2306.06817