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-rw-r--r--lib/Ordered.v30
1 files changed, 30 insertions, 0 deletions
diff --git a/lib/Ordered.v b/lib/Ordered.v
index f52a7ef..026671a 100644
--- a/lib/Ordered.v
+++ b/lib/Ordered.v
@@ -48,6 +48,36 @@ Definition eq_dec : forall x y, { eq x y } + { ~ eq x y } := peq.
End OrderedPositive.
+(** The ordered type of integers *)
+
+Module OrderedZ <: OrderedType.
+
+Definition t := Z.
+Definition eq (x y: t) := x = y.
+Definition lt := Zlt.
+
+Lemma eq_refl : forall x : t, eq x x.
+Proof (@refl_equal t).
+Lemma eq_sym : forall x y : t, eq x y -> eq y x.
+Proof (@sym_equal t).
+Lemma eq_trans : forall x y z : t, eq x y -> eq y z -> eq x z.
+Proof (@trans_equal t).
+Lemma lt_trans : forall x y z : t, lt x y -> lt y z -> lt x z.
+Proof Zlt_trans.
+Lemma lt_not_eq : forall x y : t, lt x y -> ~ eq x y.
+Proof. unfold lt, eq, t; intros. omega. Qed.
+Lemma compare : forall x y : t, Compare lt eq x y.
+Proof.
+ intros. destruct (Z.compare x y) as [] eqn:E.
+ apply EQ. red. apply Z.compare_eq_iff. assumption.
+ apply LT. assumption.
+ apply GT. apply Z.compare_gt_iff. assumption.
+Defined.
+
+Definition eq_dec : forall x y, { eq x y } + { ~ eq x y } := zeq.
+
+End OrderedZ.
+
(** The ordered type of machine integers *)
Module OrderedInt <: OrderedType.