fact: Definition subtract h1 h2 := if h1 is (Def hs1 _) then foldl (fun h x => free x h) h2 (supp hs1) else Undef.
imports: mathcomp(ssreflect ssrfun ssrnat div ssrbool seq) LemmaOverloading(prelude finmap ordtype) mathcomp(path eqtype) Eqdep