intros m; case m; auto.
intros m' H1; Contradict H1; auto.
rewrite S_INR.
apply Rlt_dichotomy_converse; left.
apply Rle_lt_0_plus_1.
apply pos_INR.
intros n' H' m; case m.
intros H'0; Contradict H'0; auto.
rewrite S_INR.
apply Rlt_dichotomy_converse; right.
red in |- *; apply Rle_lt_0_plus_1.
apply pos_INR.
intros m' H'0.
rewrite (H' m'); auto.
repeat rewrite S_INR in H'0.
apply Rplus_eq_reg_l with (r := 1%R); repeat rewrite (Rplus_comm 1);
auto with real.
Qed.

Theorem Rle_INR : forall x y : nat, x <= y -> (INR x <= INR y)%R.
intros x y H; repeat rewrite INR_IZR_INZ.