proposition: Lemma unh02 h : h :++ (empty, empty) = h.
proof: Proof. by case: h=>h1 h2; rewrite /plus2 /= !unh0. Qed.
imports: mathcomp(ssreflect ssrfun ssrnat div ssrbool seq) LemmaOverloading(prelude finmap ordtype) mathcomp(path eqtype) Eqdep