On Bounding the Diameter of the Commuting Graph of a Group

TL;DR

This paper investigates the maximum possible diameter of commuting graphs in finite groups, providing bounds for certain classes and presenting an infinite family with a diameter of 6, challenging existing assumptions.

Contribution

It establishes upper bounds on the diameter of commuting graphs for specific group classes and introduces an infinite family with a diameter of 6.

Findings

Upper bounds on commuting graph diameters for certain groups

An infinite family of groups with diameter 6

Counterexamples to previous diameter limits

Abstract

The commuting graph of a group $G$ is the simple undirected graph whose vertices are the non-central elements of $G$ and two distinct vertices are adjacent if and only if they commute. It is conjectured by Jafarzadeh and Iranmanesh that there is a universal upper bound on the diameter of the commuting graphs of finite groups when the commuting graph is connected. In this paper we determine upper bounds on the diameter of the commuting graph for some classes of groups to rule them out as possible counterexamples to this conjecture. We also give an example of an infinite family of groups with trivial centre and diameter 6, the previously largest known diameter for an infinite family was 5 for $S_n$.