proposition: Lemma finite_der_Star : forall E, Finite (set_of_der E) -> Finite (set_of_der (Star E)).
proof: Proof. move => E hE. apply: (@Bar_gset_incl _ (Union (pred_singl (Star E)) (set_of_der_star E))). apply: Bar_gset_union. by apply finite_pred_singl. by apply: finite_pred_der_star. by apply: incl_der_pred_star. Qed.
imports: Coq(RelationClasses Setoid Morphisms Permutation) Coq(SetoidList Mergesort Orders) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq fintype) mathcomp(bigop path) RegLang(languages) RegexpBrzozowski(glue gfinset regexp)