proposition: Lemma ssublNot : forall r s, ssubl (Not r) (Not s) = ssubr r s.
proof: Proof. by move => r s /=. Qed.
imports: Coq(RelationClasses Setoid Morphisms Permutation) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq fintype) mathcomp(bigop path) RegLang(languages) RegexpBrzozowski(regexp finite_der equiv)