proposition: Lemma semProdSize_return_None A s (S : set (option A)) : isNone :&: S \subset isNone :&: semProdSize (returnEnum None) s.
proof: Proof. intros x Hin. inv Hin. destruct x. now inv H. split; eauto. eapply semReturnSizeEnum. reflexivity. Qed.
imports: ZArith List mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool ssrnat) Numbers.BinNums Classes.RelationClasses ExtLib.Structures(Functor Applicative) QuickChick(Sets Tactics Producer LazyList RandomQC)