The existence of $m$-Haar graphical representations

Fuente: arXiv
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Main Authors: Du, Jia-Li, Feng, Yan-Quan, Xia, Binzhou, Yang, Da-Wei
Format: Preprint
Published: 2024
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author Du, Jia-Li
Feng, Yan-Quan
Xia, Binzhou
Yang, Da-Wei
author_facet Du, Jia-Li
Feng, Yan-Quan
Xia, Binzhou
Yang, Da-Wei
contents Extending the well-studied concept of graphical regular representations to bipartite graphs, a Haar graphical representation (HGR) of a group $G$ is a bipartite graph whose automorphism group is isomorphic to $G$ and acts semiregularly with the orbits giving the bipartition. The question of which groups admit an HGR was inspired by a closely related question of Estélyi and Pisanski in 2016, as well as Babai's work in 1980 on poset representations, and has been recently solved by Morris and Spiga. In this paper, we introduce the $m$-Haar graphical representation ($m$-HGR) as a natural generalization of HGR to $m$-partite graphs for $m\geq2$, and explore the existence of $m$-HGRs for any fixed group. This inquiry represents a more robust version of the existence problem of G$m$SRs as addressed by Du, Feng and Spiga in 2020. Our main result is a complete classification of finite groups $G$ without $m$-HGRs.
format Preprint
id arxiv_https___arxiv_org_abs_2409_18716
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The existence of $m$-Haar graphical representations
Du, Jia-Li
Feng, Yan-Quan
Xia, Binzhou
Yang, Da-Wei
Combinatorics
Extending the well-studied concept of graphical regular representations to bipartite graphs, a Haar graphical representation (HGR) of a group $G$ is a bipartite graph whose automorphism group is isomorphic to $G$ and acts semiregularly with the orbits giving the bipartition. The question of which groups admit an HGR was inspired by a closely related question of Estélyi and Pisanski in 2016, as well as Babai's work in 1980 on poset representations, and has been recently solved by Morris and Spiga. In this paper, we introduce the $m$-Haar graphical representation ($m$-HGR) as a natural generalization of HGR to $m$-partite graphs for $m\geq2$, and explore the existence of $m$-HGRs for any fixed group. This inquiry represents a more robust version of the existence problem of G$m$SRs as addressed by Du, Feng and Spiga in 2020. Our main result is a complete classification of finite groups $G$ without $m$-HGRs.
title The existence of $m$-Haar graphical representations
topic Combinatorics
url https://arxiv.org/abs/2409.18716