proposition: Lemma unKhr h h1 h2 : def (h2 :+ h) -> h1 :+ h = h2 :+ h -> h1 = h2.
proof: Proof. by move=>H1 H2; symmetry in H2; rewrite (unKhl H1 H2). Qed.
imports: mathcomp(ssreflect ssrfun ssrnat div ssrbool seq) LemmaOverloading(prelude finmap ordtype) mathcomp(path eqtype) Eqdep