Minimality of the inner automorphism group

Fuente: arXiv
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Main Authors: Peng, Dekui, Shlossberg, Menachem
Format: Preprint
Published: 2023
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author Peng, Dekui
Shlossberg, Menachem
author_facet Peng, Dekui
Shlossberg, Menachem
contents By [6], a minimal group $G$ is called $z$-minimal if $G/Z(G)$ is minimal. In this paper, we present the $z$-Minimality Criterion for dense subgroups with some applications to topological matrix groups. For a locally compact group $G$, let $\operatorname{Inn}(G)$ be the group of all inner automorphisms of $G,$ endowed with the Birkhoff topology. Using a theorem by Goto [14], we obtain our main result which asserts that if $G$ is a connected Lie group and $H\in\{G/Z(G), \operatorname{Inn}(G)\},$ then $H$ is minimal if and only if it is centre-free and topologically isomorphic to $\operatorname{Inn}(G/Z(G)).$ In particular, if $G$ is a connected Lie group with discrete centre, then $\operatorname{Inn}(G)$ is minimal. We prove that a connected locally compact nilpotent group is $z$-minimal if and only if it is compact abelian. In contrast, we show that there exists a connected metabelian $z$-minimal Lie group that is neither compact nor abelian.
format Preprint
id arxiv_https___arxiv_org_abs_2309_17065
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Minimality of the inner automorphism group
Peng, Dekui
Shlossberg, Menachem
General Topology
Group Theory
Number Theory
By [6], a minimal group $G$ is called $z$-minimal if $G/Z(G)$ is minimal. In this paper, we present the $z$-Minimality Criterion for dense subgroups with some applications to topological matrix groups. For a locally compact group $G$, let $\operatorname{Inn}(G)$ be the group of all inner automorphisms of $G,$ endowed with the Birkhoff topology. Using a theorem by Goto [14], we obtain our main result which asserts that if $G$ is a connected Lie group and $H\in\{G/Z(G), \operatorname{Inn}(G)\},$ then $H$ is minimal if and only if it is centre-free and topologically isomorphic to $\operatorname{Inn}(G/Z(G)).$ In particular, if $G$ is a connected Lie group with discrete centre, then $\operatorname{Inn}(G)$ is minimal. We prove that a connected locally compact nilpotent group is $z$-minimal if and only if it is compact abelian. In contrast, we show that there exists a connected metabelian $z$-minimal Lie group that is neither compact nor abelian.
title Minimality of the inner automorphism group
topic General Topology
Group Theory
Number Theory
url https://arxiv.org/abs/2309.17065