proposition: Lemma quotient_astabQ H Abar : 'C(Abar | 'Q) / H = 'C(Abar).
proof: Proof. by rewrite astabQ cosetpreK. Qed.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat div seq) mathcomp(fintype bigop finset fingroup morphism perm) mathcomp(automorphism quotient)