An Arad and Fisman's theorem on products of conjugacy classes revisited

Antonio Beltrán, María José Felipe, Carmen Melchor

A theorem of Z. Arad and E. Fisman establishes that if $A$ and $B$ are two conjugacy classes of a finite group $G$ such that either $AB=A\cup B$ or $AB=A^{-1}\cup B$, then $G$ can…