proposition: Lemma mmax_uniq_id : {subset 'M <= 'U}.
proof: Proof. by move=> M maxM; apply/uniq_mmaxP; exists M; apply: mmax_sup_id. Qed.
imports: HB(structures) mathcomp.ssreflect.ssreflect mathcomp(ssrbool ssrfun eqtype ssrnat seq div choice fintype bigop) mathcomp(finset prime fingroup morphism automorphism action quotient) mathcomp(gfunctor cyclic pgroup center commutator gseries nilpotent) mathcomp(sylow abelian maximal hall) odd_order(BGsection1 BGsection6)