proposition: Lemma zero_fun_nneg : forall X : CSetoid, nneg (Zero_fun X).
proof: Proof. intro X. unfold nneg in |- *. intros x y. unfold Zero_fun in |- *. simpl in |- *. unfold zero_fun in |- *. apply eq_imp_leEq. intuition. Qed.
imports: CoRN.reals.Intervals