Enveloping Ellis semigroups as compactifications of transformations groups

Fuente: arXiv
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Auteurs principaux: Kozlov, K. L., Sorin, B. V.
Format: Preprint
Publié: 2024
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author Kozlov, K. L.
Sorin, B. V.
author_facet Kozlov, K. L.
Sorin, B. V.
contents The notion of a proper Ellis semigroup compactification is introduced. Ellis's functional approach shows how to obtain them from totally bounded equiuniformities on a phase space $X$ when the acting group $G$ is with the topology of pointwise convergence and the $G$-space $(G, X, \curvearrowright)$ is $G$-Tychonoff. The correspondence between proper Ellis semigroup compactifications of a topological group and special totally bounded equiuniformities (called Ellis equiuniformities) on a topological group is established. The Ellis equiuniformity on a topological transformation group $G$ from the maximal equiuniformity on a phase space $G/H$ in the case of its uniformly equicontinuous action is compared with Roelcke uniformity on $G$. Proper Ellis semigroup compactifications are described for groups $S\,(X)$ (the permutation group of a discrete space $X$) and $Aut\,(X)$ (automorphism group of an ultrahomogeneous chain $X$) in the permutation topology. It is shown that this approach can be applied to the unitary group of a Hilbert space.
format Preprint
id arxiv_https___arxiv_org_abs_2412_04281
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Enveloping Ellis semigroups as compactifications of transformations groups
Kozlov, K. L.
Sorin, B. V.
General Topology
Group Theory
Primary 57S05, 20E22 Secondary 22F05, 22F50, 54E05, 54D35, 54H15, 47B02
The notion of a proper Ellis semigroup compactification is introduced. Ellis's functional approach shows how to obtain them from totally bounded equiuniformities on a phase space $X$ when the acting group $G$ is with the topology of pointwise convergence and the $G$-space $(G, X, \curvearrowright)$ is $G$-Tychonoff. The correspondence between proper Ellis semigroup compactifications of a topological group and special totally bounded equiuniformities (called Ellis equiuniformities) on a topological group is established. The Ellis equiuniformity on a topological transformation group $G$ from the maximal equiuniformity on a phase space $G/H$ in the case of its uniformly equicontinuous action is compared with Roelcke uniformity on $G$. Proper Ellis semigroup compactifications are described for groups $S\,(X)$ (the permutation group of a discrete space $X$) and $Aut\,(X)$ (automorphism group of an ultrahomogeneous chain $X$) in the permutation topology. It is shown that this approach can be applied to the unitary group of a Hilbert space.
title Enveloping Ellis semigroups as compactifications of transformations groups
topic General Topology
Group Theory
Primary 57S05, 20E22 Secondary 22F05, 22F50, 54E05, 54D35, 54H15, 47B02
url https://arxiv.org/abs/2412.04281