proposition: Lemma pi_p'group p pi A : pi.-group A -> p \in pi^' -> p^'.-group A.
proof: Proof. exact: pi_p'nat. Qed.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq div) mathcomp(fintype bigop finset prime fingroup morphism) mathcomp(gfunctor automorphism quotient action gproduct) mathcomp(cyclic)