proposition: Lemma iter_plus_1 : forall p q, iter (p+q+1) << iter p @ iter q.
proof: Proof. induction p; simpl; intros. rewrite plus_1_S. simpl. refl. incl_trans (R @ (iter p @ iter q)). comp. apply IHp. apply comp_assoc'. Qed.
imports: Coq(List) CoLoR(Path NatUtil RelUtil LogicUtil Log2)