Locally Compact Groups with All Dense Subgroups Separable

Fuente: arXiv
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Autor principal: Peng, Dekui
Formato: Preprint
Publicado: 2023
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author Peng, Dekui
author_facet Peng, Dekui
contents By a recent result of Juhász and van Mill, a locally compact topological group whose dense subspaces are all separable is metrizable. In this note we investigate the following question: is every locally compact group having all dense subgroups separable also metrizable? We give an example to show the answer is negative for locally compact abelian groups, thereby showing that one cannot directly generalize the assertion by replacing ``subspaces'' with ``subgroups''. On the other hand, we prove that the answer is positive for compact groups which are either connected or algebraically abelian; and for locally compact groups containing only separable subgroups. As an application, we obtain a necessary condition for metrizability of pronilpotent groups.
format Preprint
id arxiv_https___arxiv_org_abs_2303_06426
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Locally Compact Groups with All Dense Subgroups Separable
Peng, Dekui
Group Theory
General Topology
22C05, 22D05, 54A25
By a recent result of Juhász and van Mill, a locally compact topological group whose dense subspaces are all separable is metrizable. In this note we investigate the following question: is every locally compact group having all dense subgroups separable also metrizable? We give an example to show the answer is negative for locally compact abelian groups, thereby showing that one cannot directly generalize the assertion by replacing ``subspaces'' with ``subgroups''. On the other hand, we prove that the answer is positive for compact groups which are either connected or algebraically abelian; and for locally compact groups containing only separable subgroups. As an application, we obtain a necessary condition for metrizability of pronilpotent groups.
title Locally Compact Groups with All Dense Subgroups Separable
topic Group Theory
General Topology
22C05, 22D05, 54A25
url https://arxiv.org/abs/2303.06426