Counterexamples to a conjecture of M. Pellegrini and P. Shumyatsky

Abstract

In this article, we provide counterexamples to a conjecture of M. Pellegrini and P. Shumyatsky which states that each coset of the centralizer of an involution in a finite non-abelian simple group $G$ contains an odd order element, unless $G=\text{PSL}(n,2)$ for $n\ge 4$. More precisely, we show that the conjecture does not hold for the alternating group $A_{8n}$ for all $n\ge 2$.