proposition: Lemma SylowJ G P x : x \in G -> Sylow G (P :^ x) = Sylow G P.
proof: Proof. by move=> Gx; rewrite /Sylow p_groupJ HallJ. 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)