proposition: Lemma toolmkConc : forall r, [ \/ r == CVoid , r == CEps , (exists l, r == CConc l) | [ /\ r != CVoid , r != CEps & (forall l, r != CConc l) ] ].
proof: Proof. case => [ | | | s | c | l | l | l | c ] //=; try by apply: Or44. - by apply: Or41. - by apply: Or42. - by apply: Or43; exists l. 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)