Section CPair_Order.
intros.
apply le_trans with (cPair (cPairPi1 a) (cPairPi2 a)).
apply cPairLe1.
rewrite cPairProjections.
apply le_n.
Qed.
intros.
apply le_trans with (cPair (cPairPi1 a) (cPairPi2 a)).
apply cPairLe2.
rewrite cPairProjections.
apply le_n.
Qed.

Lemma cPairLt2 : forall a b : nat, b < cPair (S a) b.