proposition: Lemma eq_pHall pi rho G H : pi =i rho -> pi.-Hall(G) H = rho.-Hall(G) H.
proof: Proof. by move=> eq_pi_rho; apply: eq_in_pHall (in1W eq_pi_rho). 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)