On combinatorial properties of Gruenberg--Kegel graphs of finite groups

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Chen, Mingzhu, Gorshkov, Ilya B., Maslova, Natalia V., Yang, Nanying
Format: Preprint
Published: 2024
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866908327131217920
author Chen, Mingzhu
Gorshkov, Ilya B.
Maslova, Natalia V.
Yang, Nanying
author_facet Chen, Mingzhu
Gorshkov, Ilya B.
Maslova, Natalia V.
Yang, Nanying
contents If $G$ is a finite group, then the spectrum $ω(G)$ is the set of all element orders of $G$. The prime spectrum $π(G)$ is the set of all primes belonging to $ω(G)$. A simple graph $Γ(G)$ whose vertex set is $π(G)$ and in which two distinct vertices $r$ and $s$ are adjacent if and only if $rs \in ω(G)$ is called the Gruenberg-Kegel graph or the prime graph of $G$. In this paper, we prove that if $G$ is a group of even order, then the set of vertices which are non-adjacent to $2$ in $Γ(G)$ form a union of cliques. Moreover, we decide when a strongly regular graph is isomorphic to the Gruenberg-Kegel graph of a finite group. Besides this, we prove that a complete bipartite graph with each part of size at least $3$ can not be isomorphic to the Gruenberg-Kegel graph of a finite group.
format Preprint
id arxiv_https___arxiv_org_abs_2401_04789
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On combinatorial properties of Gruenberg--Kegel graphs of finite groups
Chen, Mingzhu
Gorshkov, Ilya B.
Maslova, Natalia V.
Yang, Nanying
Group Theory
Combinatorics
20D60, 05C25
If $G$ is a finite group, then the spectrum $ω(G)$ is the set of all element orders of $G$. The prime spectrum $π(G)$ is the set of all primes belonging to $ω(G)$. A simple graph $Γ(G)$ whose vertex set is $π(G)$ and in which two distinct vertices $r$ and $s$ are adjacent if and only if $rs \in ω(G)$ is called the Gruenberg-Kegel graph or the prime graph of $G$. In this paper, we prove that if $G$ is a group of even order, then the set of vertices which are non-adjacent to $2$ in $Γ(G)$ form a union of cliques. Moreover, we decide when a strongly regular graph is isomorphic to the Gruenberg-Kegel graph of a finite group. Besides this, we prove that a complete bipartite graph with each part of size at least $3$ can not be isomorphic to the Gruenberg-Kegel graph of a finite group.
title On combinatorial properties of Gruenberg--Kegel graphs of finite groups
topic Group Theory
Combinatorics
20D60, 05C25
url https://arxiv.org/abs/2401.04789