From d8a2c246510af26104fb16fb8ac7c266341c2f8b Mon Sep 17 00:00:00 2001
From: emakarov
Date: Thu, 20 Sep 2007 18:24:50 +0000
Subject: Changed the definition of Nminus in BinNat.v by removing comparison.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10130 85f007b7-540e-0410-9357-904b9bb8a0f7
---
 contrib/setoid_ring/Ring_zdiv.v | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

(limited to 'contrib')

diff --git a/contrib/setoid_ring/Ring_zdiv.v b/contrib/setoid_ring/Ring_zdiv.v
index 9b102c28c8..44874e5474 100644
--- a/contrib/setoid_ring/Ring_zdiv.v
+++ b/contrib/setoid_ring/Ring_zdiv.v
@@ -40,10 +40,9 @@ destruct a; intros; simpl; auto.
   rewrite (Pcompare_Eq_eq _ _ H).
   assert (HH: forall p, Pminus p p = xH).
     intro p0; unfold Pminus; rewrite Pminus_mask_diag; auto.
-  simpl; auto.
-  generalize (Pplus_minus _ _ H).
-  case (p - b)%positive; intros; subst;
-  unfold Nplus; rewrite Pplus_comm; trivial.
+  apply Pcompare_Eq_eq in H. now rewrite Pminus_mask_diag.
+  pose proof (Pminus_mask_Gt p b H) as H1. destruct H1 as [d [H2 [H3 _]]].
+  rewrite H2. rewrite <- H3. unfold Nplus. now rewrite Pplus_comm.
 Qed.
 
 Theorem Z_of_N_plus: 
-- 
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