fact: Fixpoint Finite_Union (n:nat) : prodn gset n -> gset := match n with | 0 => fun _ => Empty_gset | S _ => fun es => let (hd,tl) := es in Union hd (Finite_Union tl) end.
imports: Coq(RelationClasses Setoid Morphisms SetoidList Mergesort Permutation) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq fintype) mathcomp(bigop path) RegexpBrzozowski(glue)