X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fmatita%2Flibrary%2FZ%2Fz.ma;h=ac530c38fe02b7df1766fd69ff93a637162131b0;hb=7a116453d799657958e32693be28d18a5aab84fc;hp=9532ea95deb4d3ffb2a7c66b1665f58aa7a6c462;hpb=68a2f8d0a8c34cb7ea0438c7db9222a853a38826;p=helm.git

diff --git a/helm/software/matita/library/Z/z.ma b/helm/software/matita/library/Z/z.ma
index 9532ea95d..ac530c38f 100644
--- a/helm/software/matita/library/Z/z.ma
+++ b/helm/software/matita/library/Z/z.ma
@@ -34,6 +34,11 @@ definition neg_Z_of_nat \def
 [ O \Rightarrow  OZ 
 | (S n)\Rightarrow  neg n].
 
+lemma pos_n_eq_S_n : \forall n : nat.
+  (pos n) = (S n).
+intro.reflexivity. 
+qed.
+
 definition abs \def
 \lambda z.
  match z with 
@@ -55,9 +60,9 @@ match OZ_test z with
 intros.elim z.
 simplify.reflexivity.
 simplify. unfold Not. intros (H).
-discriminate H.
+destruct H.
 simplify. unfold Not. intros (H).
-discriminate H.
+destruct H.
 qed.
 
 (* discrimination *)
@@ -85,17 +90,17 @@ variant inj_neg : \forall n,m:nat. neg n = neg m \to n = m
 
 theorem not_eq_OZ_pos: \forall n:nat. OZ \neq pos n.
 unfold Not.intros (n H).
-discriminate H.
+destruct H.
 qed.
 
 theorem not_eq_OZ_neg :\forall n:nat. OZ \neq neg n.
 unfold Not.intros (n H).
-discriminate H.
+destruct H.
 qed.
 
 theorem not_eq_pos_neg :\forall n,m:nat. pos n \neq neg m.
 unfold Not.intros (n m H).
-discriminate H.
+destruct H.
 qed.
 
 theorem decidable_eq_Z : \forall x,y:Z. decidable (x=y).
@@ -117,7 +122,7 @@ elim x.
   (* goal: x=pos y=pos *)
     elim (decidable_eq_nat n n1:((n=n1) \lor ((n=n1) \to False))).
     left.apply eq_f.assumption.
-    right.unfold Not.intros (H_inj).apply H. injection H_inj. assumption.
+    right.unfold Not.intros (H_inj).apply H. destruct H_inj. reflexivity.
   (* goal: x=pos y=neg *)
     right.unfold Not.intro.apply (not_eq_pos_neg n n1). assumption.
 (* goal: x=neg *)