Pos Groups Revisited

A finite group $G$ is said to be a POS-group if for each $ x $ in $G$ the cardinality of the set $\{y \in G | o(y) =o(x)\}$ is a divisor of the order of $G$. In this paper we study some of the properties of arbitrary POS-groups, and construct a couple of new families of nonabelian POS-groups. We also prove that the alternating group $A_n$, $n \ge 3$, is not a POS-group.