proposition: Lemma isog_narrow G R : G \isog R -> p.-narrow G = p.-narrow R.
proof: Proof. by case/isogP=> f injf <-; rewrite injm_narrow. Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(ssrbool ssrfun eqtype ssrnat seq div) mathcomp(fintype finset prime fingroup morphism perm automorphism action) mathcomp(quotient cyclic gfunctor pgroup gproduct center commutator) mathcomp(gseries nilpotent sylow abelian maximal hall) odd_order(BGsection1 BGsection4)