proposition: Lemma R_reg_empty : forall l r, In (l,r) nil -> forall v, In v (var_list r) -> In v (var_list l).
proof: Proof. intros l r H; case H. Qed.
imports: Coq(List Relations Wellfounded Arith Recdef Setoid) CoLoR(closure more_list weaved_relation term equational_theory_spec dp)