proposition: Lemma maxainv_ainvar : maxainv K N -> A \subset 'N(N | to).
proof: Proof. by move/maxgroupp; case/and3P. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(choice fintype bigop finset fingroup morphism) mathcomp(automorphism quotient action gseries)