-systems of finite simple groups
For a finite group denote by the set of conjugacy class sizes of . In 1980s, J. G. Thompson posed the following conjecture: If is a finite nonabelian simple group, is a finite group with trivial center and , then . We prove this conjecture for an infinite class of simple groups. Let be an odd prime. We show that every finite group with the property and is necessarily isomorphic to , where .