fact: Fixpoint DER1 l := match l with | [::] => [::] | (hd,s) :: tl => [:: (der1 hd,true::s) , (der0 hd,false::s) & DER1 tl ] end.
imports: Coq(RelationClasses) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq fintype) mathcomp(bigop path) RegLang(languages) RegexpBrzozowski(glue gfinset regexp finite_der)