Document Type : Research Paper
Authors
1 Technical Instructors Training Institute, Middle Technical University, Baghdad, Iraq
2 Technical Engineering College, Middle Technical University, Baghdad, Iraq
3 College of Physical Education and Sports Science, University of Baghdad, Baghdad, Iraq
4 Middle Technical University, Technical Instructors Training Institute, Iraq
Abstract
Let $t$ be an elements of order 3 in a finite simple group $\mathrm{G}$. Let $\mathrm{X}=t^{\mathrm{G}}$ be a conjugacy class of $t$ in $\mathrm{G}$. The A4-graph, represented as $A_{4}(\mathrm{G}, \mathrm{X})$, is a simple graph has $\mathrm{X}$ as a vertex set and two vertices $x, y \in \mathrm{X}$, joined by edge whenever $\mathrm{x} \neq \mathrm{y}$ and $x y^{-1}=y x^{-1}$. In this paper, we investigate the discs structure and determine the clique number, girth and diameter of $A_{4}(\mathrm{G}, \mathrm{X})$ when $\mathrm{G}$ is isomorphic to one of the untwisted groups $\mathrm{G}_{2}(2)^{\prime}, \mathrm{G}_{2}(3)$ or $\mathrm{G}_{2}(4)$.
Keywords