fact: Fixpoint rPlus a (l: seq regexp) := match l with | [::] => a | hd :: tl => Plus (rPlus a tl) hd end.
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)