fact: Variable similar_ok : forall c1 c2, similar c1 c2 -> (c1 =i c2).
imports: Coq(RelationClasses) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq fintype) mathcomp(bigop path) RegLang(languages) RegexpBrzozowski(glue gfinset regexp finite_der)