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-rw-r--r--src/Util/ZUtil.v16
1 files changed, 14 insertions, 2 deletions
diff --git a/src/Util/ZUtil.v b/src/Util/ZUtil.v
index d06477d3c..35aa20dc4 100644
--- a/src/Util/ZUtil.v
+++ b/src/Util/ZUtil.v
@@ -324,15 +324,27 @@ Module Z.
Hint Resolve elim_mod : zarith.
+ Lemma mod_add_full : forall a b c, (a + b * c) mod c = a mod c.
+ Proof. intros; destruct (Z_zerop c); try subst; autorewrite with zsimplify; reflexivity. Qed.
+ Hint Rewrite mod_add_full : zsimplify.
+
+ Lemma mod_add_l_full : forall a b c, (a * b + c) mod b = c mod b.
+ Proof. intros; rewrite (Z.add_comm _ c); autorewrite with zsimplify; reflexivity. Qed.
+ Hint Rewrite mod_add_l_full : zsimplify.
+
+ Lemma mod_add'_full : forall a b c, (a + b * c) mod b = a mod b.
+ Proof. intros; rewrite (Z.mul_comm _ c); autorewrite with zsimplify; reflexivity. Qed.
+ Lemma mod_add_l'_full : forall a b c, (a * b + c) mod a = c mod a.
+ Proof. intros; rewrite (Z.mul_comm _ b); autorewrite with zsimplify; reflexivity. Qed.
+ Hint Rewrite mod_add'_full mod_add_l'_full : zsimplify.
+
Lemma mod_add_l : forall a b c, b <> 0 -> (a * b + c) mod b = c mod b.
Proof. intros; rewrite (Z.add_comm _ c); autorewrite with zsimplify; reflexivity. Qed.
- Hint Rewrite mod_add_l using zutil_arith : zsimplify.
Lemma mod_add' : forall a b c, b <> 0 -> (a + b * c) mod b = a mod b.
Proof. intros; rewrite (Z.mul_comm _ c); autorewrite with zsimplify; reflexivity. Qed.
Lemma mod_add_l' : forall a b c, a <> 0 -> (a * b + c) mod a = c mod a.
Proof. intros; rewrite (Z.mul_comm _ b); autorewrite with zsimplify; reflexivity. Qed.
- Hint Rewrite mod_add' mod_add_l' using zutil_arith : zsimplify.
Lemma pos_pow_nat_pos : forall x n,
Z.pos x ^ Z.of_nat n > 0.