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-rw-r--r--src/Util/NatUtil.v16
1 files changed, 14 insertions, 2 deletions
diff --git a/src/Util/NatUtil.v b/src/Util/NatUtil.v
index 5c65148c0..344eb40c9 100644
--- a/src/Util/NatUtil.v
+++ b/src/Util/NatUtil.v
@@ -10,7 +10,7 @@ Hint Resolve (fun x y p q => proj1 (@Nat.mod_bound_pos x y p q)) (fun x y p q =>
Hint Rewrite @mod_small @mod_mod @mod_1_l @mod_1_r succ_pred using omega : natsimplify.
-Hint Rewrite sub_diag add_0_l add_0_r sub_0_r : natsimplify.
+Hint Rewrite sub_diag add_0_l add_0_r sub_0_r sub_succ : natsimplify.
Local Open Scope nat_scope.
@@ -66,7 +66,7 @@ Proof.
reflexivity.
Qed.
-Lemma pred_mod : forall m, (0 < m)%nat -> ((pred m) mod m)%nat = pred m.
+Lemma pred_mod : forall m, (0 < m)%nat -> ((pred m) mod m)%nat = pred m.
Proof.
intros; apply Nat.mod_small.
destruct m; try omega; rewrite Nat.pred_succ; auto.
@@ -291,3 +291,15 @@ Proof.
apply f_equal, le_unique.
Qed.
Hint Rewrite le_dec_pred_plus_same : natsimplify.
+
+Lemma minus_S_diag x : (S x - x = 1)%nat.
+Proof. omega. Qed.
+Hint Rewrite minus_S_diag : natsimplify.
+
+Lemma min_idempotent_S_l x : min (S x) x = x.
+Proof. omega *. Qed.
+Hint Rewrite min_idempotent_S_l : natsimplify.
+
+Lemma min_idempotent_S_r x : min x (S x) = x.
+Proof. omega *. Qed.
+Hint Rewrite min_idempotent_S_r : natsimplify.