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(** Order on natural numbers.  This file is mostly OBSOLETE now, see module [PeanoNat.Nat] instead.  [le] is defined in [Init/Peano.v] as: << Inductive le (n:nat) : nat -> Prop := | le_n : n <= n | le_S : forall m:nat, n <= m -> n <= S m  where "n <= m" := (le n m) : nat_scope. >> *)
Local Open Scope nat_scope.
(** * [le] is an order on [nat] *)
Notation le_refl := Nat.le_refl (only parsing).
Notation le_trans := Nat.le_trans (only parsing).
Notation le_antisym := Nat.le_antisymm (only parsing).
Hint Resolve le_trans: arith.
Hint Immediate le_antisym: arith.
(** * Properties of [le] w.r.t 0 *)
Notation le_0_n := Nat.le_0_l (only parsing).  (* 0 <= n *)
Notation le_Sn_0 := Nat.nle_succ_0 (only parsing).  (* ~ S n <= 0 *)

Lemma le_n_0_eq n : n <= 0 -> 0 = n.