proposition: Lemma eq_p'group pi rho A : pi =i rho -> pi^'.-group A = rho^'.-group A.
proof: Proof. by move/eq_negn; apply: eq_pnat. 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)