proposition: Lemma maximalJ x : maximal (G :^ x) (H :^ x) = maximal G H.
proof: Proof. rewrite -{1}(setTI G) -{1}(setTI H) -!morphim_conj. by rewrite injm_maximal ?subsetT ?injm_conj. Qed.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq path) mathcomp(fintype bigop finset fingroup morphism) mathcomp(automorphism quotient action commutator center)