proposition: Lemma in_All : forall u, (u \in Not Void).
proof: Proof. move => u; rewrite -topredE /=. by apply/negP. Qed.
imports: Coq(RelationClasses Setoid Morphisms) HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq fintype) mathcomp(bigop path) RegLang(languages) RegexpBrzozowski(glue regexp finite_der equiv)