Compact Group Homeomorphisms Preserving The Haar Measure

Fuente: arXiv
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Main Author: Liu, Gang
Format: Preprint
Published: 2025
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author Liu, Gang
author_facet Liu, Gang
contents This paper studies the measure-preserving homeomorphisms on compact groups and proposes new methods for constructing measure-preserving homeomorphisms on direct products of compact groups and non-commutative compact groups. On the direct product of compact groups, we construct measure-preserving homeomorphisms using the method of integration. In particular, by applying this method to the \(n\)-dimensional torus \({\mathbb{T}}^{n}\), we can construct many new examples of measure-preserving homeomorphisms. We completely characterize the measure-preserving homeomorphisms on the two-dimensional torus where one coordinate is a translation depending on the other coordinate, and generalize this result to the \(n\)-dimensional torus. For non-commutative compact groups, we generalize the concept of the normalizer subgroup \(N\left( H\right)\) of the subgroup \(H\) to the normalizer subset \({E}_{K}( P)\) from the subset \(K\) to the subset \(P\) of the group of measure-preserving homeomorphisms. We prove that if \(μ\) is the unique \(K\)-invariant measure, then the elements in \({E}_{K}\left( P\right)\) also preserve \(μ\). In some non-commutative compact groups the normalizer subset \({E}_{G}\left( {\mathrm{AF}\left( G\right) }\right)\) can give non-affine homeomorphisms that preserve the Haar measure. Finally, we prove that when \(G\) is a finite cyclic group and a \(n\)-dimensional torus, then \(\mathrm{AF}\left( G\right)= N\left( G\right) = {E}_{G}\left( {\mathrm{AF}\left( G\right) }\right)\).
format Preprint
id arxiv_https___arxiv_org_abs_2504_01760
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Compact Group Homeomorphisms Preserving The Haar Measure
Liu, Gang
Dynamical Systems
This paper studies the measure-preserving homeomorphisms on compact groups and proposes new methods for constructing measure-preserving homeomorphisms on direct products of compact groups and non-commutative compact groups. On the direct product of compact groups, we construct measure-preserving homeomorphisms using the method of integration. In particular, by applying this method to the \(n\)-dimensional torus \({\mathbb{T}}^{n}\), we can construct many new examples of measure-preserving homeomorphisms. We completely characterize the measure-preserving homeomorphisms on the two-dimensional torus where one coordinate is a translation depending on the other coordinate, and generalize this result to the \(n\)-dimensional torus. For non-commutative compact groups, we generalize the concept of the normalizer subgroup \(N\left( H\right)\) of the subgroup \(H\) to the normalizer subset \({E}_{K}( P)\) from the subset \(K\) to the subset \(P\) of the group of measure-preserving homeomorphisms. We prove that if \(μ\) is the unique \(K\)-invariant measure, then the elements in \({E}_{K}\left( P\right)\) also preserve \(μ\). In some non-commutative compact groups the normalizer subset \({E}_{G}\left( {\mathrm{AF}\left( G\right) }\right)\) can give non-affine homeomorphisms that preserve the Haar measure. Finally, we prove that when \(G\) is a finite cyclic group and a \(n\)-dimensional torus, then \(\mathrm{AF}\left( G\right)= N\left( G\right) = {E}_{G}\left( {\mathrm{AF}\left( G\right) }\right)\).
title Compact Group Homeomorphisms Preserving The Haar Measure
topic Dynamical Systems
url https://arxiv.org/abs/2504.01760