--- /dev/null
+(**************************************************************************)
+(* ___ *)
+(* ||M|| *)
+(* ||A|| A project by Andrea Asperti *)
+(* ||T|| *)
+(* ||I|| Developers: *)
+(* ||T|| The HELM team. *)
+(* ||A|| http://helm.cs.unibo.it *)
+(* \ / *)
+(* \ / This file is distributed under the terms of the *)
+(* v GNU General Public License Version 2 *)
+(* *)
+(**************************************************************************)
+
+
+
+include "NLE/inv.ma".
+
+theorem nle_refl: ∀x. x ≤ x.
+ intros; elim x; clear x; autobatch.
+qed.
+
+theorem nle_trans: ∀x,y. x ≤ y → ∀z. y ≤ z → x ≤ z.
+ intros 3; elim H; clear H x y;
+ [ autobatch
+ | lapply linear nle_inv_succ_1 to H3. decompose. destruct.
+ autobatch
+ ].
+qed.
+
+theorem nle_false: ∀x,y. x ≤ y → y < x → False.
+ intros 3; elim H; clear H x y; autobatch.
+qed.
+
+theorem nle_irrefl: ∀x. x < x → False.
+ intros. autobatch.
+qed.
+
+theorem nle_irrefl_ei: ∀x, z. z ≤ x → z = succ x → False.
+ intros 3; elim H; clear H x z; destruct; autobatch.
+qed.
+
+theorem nle_irrefl_smart: ∀x. x < x → False.
+ intros 1. elim x; clear x; autobatch.
+qed.
+
+theorem nle_lt_or_eq: ∀y, x. x ≤ y → x < y ∨ x = y.
+ intros; elim H; clear H x y;
+ [ elim n; clear n
+ | decompose
+ ]; autobatch.
+qed.