Lifting Generators in Connected Lie Groups

Fuente: arXiv
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Autores principales: Cohen, Tal, Vigdorovich, Itamar
Formato: Preprint
Publicado: 2024
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author Cohen, Tal
Vigdorovich, Itamar
author_facet Cohen, Tal
Vigdorovich, Itamar
contents Given an epimorphism between topological groups $f:G\to H$, when can a generating set of $H$ be lifted to a generating set of $G$? We show that for connected Lie groups the problem is fundamentally abelian: generators can be lifted if and only if they can be lifted in the induced map between the abelianisations (assuming the number of generators is at least the minimal number of generators of $G$). As a consequence, we deduce that connected perfect Lie groups satisfy the Gaschütz lemma: generating sets of quotients can always be lifted. If the Lie group is not perfect, this may fail. The extent to which a group fails to satisfy the Gaschütz lemma is measured by its \emph{Gaschütz rank}, which we bound for all connected Lie groups, and compute exactly in most cases. Additionally, we compute the maximal size of an irredundant generating set of connected abelian Lie groups, and discuss connections between such generation problems with the Wiegold conjecture.
format Preprint
id arxiv_https___arxiv_org_abs_2411_12445
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Lifting Generators in Connected Lie Groups
Cohen, Tal
Vigdorovich, Itamar
Group Theory
Given an epimorphism between topological groups $f:G\to H$, when can a generating set of $H$ be lifted to a generating set of $G$? We show that for connected Lie groups the problem is fundamentally abelian: generators can be lifted if and only if they can be lifted in the induced map between the abelianisations (assuming the number of generators is at least the minimal number of generators of $G$). As a consequence, we deduce that connected perfect Lie groups satisfy the Gaschütz lemma: generating sets of quotients can always be lifted. If the Lie group is not perfect, this may fail. The extent to which a group fails to satisfy the Gaschütz lemma is measured by its \emph{Gaschütz rank}, which we bound for all connected Lie groups, and compute exactly in most cases. Additionally, we compute the maximal size of an irredundant generating set of connected abelian Lie groups, and discuss connections between such generation problems with the Wiegold conjecture.
title Lifting Generators in Connected Lie Groups
topic Group Theory
url https://arxiv.org/abs/2411.12445