proposition: Lemma dom_qactJ H : qact_dom 'J H = 'N(H).
proof: Proof. by rewrite qact_domE ?subsetT ?astabsJ. Qed.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat div seq) mathcomp(fintype bigop finset fingroup morphism perm) mathcomp(automorphism quotient)