X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fmatita%2Flibrary%2Fnat%2Fplus.ma;h=d595dad19113cb6626ec4e58cc1e8a2d389be2b1;hb=97c2d258a5c524eb5c4b85208899d80751a2c82f;hp=39e48f21e58a85811b1eb99e4666cb0c89dcaea3;hpb=633474751ddf1074947ff0d324fb1aca2293eff8;p=helm.git

diff --git a/helm/matita/library/nat/plus.ma b/helm/matita/library/nat/plus.ma
index 39e48f21e..d595dad19 100644
--- a/helm/matita/library/nat/plus.ma
+++ b/helm/matita/library/nat/plus.ma
@@ -21,55 +21,52 @@ let rec plus n m \def
  [ O \Rightarrow m
  | (S p) \Rightarrow S (plus p m) ].
 
-theorem plus_n_O: \forall n:nat. n = plus n O.
+(*CSC: the URI must disappear: there is a bug now *)
+interpretation "natural plus" 'plus x y = (cic:/matita/nat/plus/plus.con x y).
+
+theorem plus_n_O: \forall n:nat. n = n+O.
 intros.elim n.
 simplify.reflexivity.
 simplify.apply eq_f.assumption.
 qed.
 
-theorem plus_n_Sm : \forall n,m:nat. S (plus n  m) = plus n (S m).
+theorem plus_n_Sm : \forall n,m:nat. S (n+m) = n+(S m).
 intros.elim n.
 simplify.reflexivity.
 simplify.apply eq_f.assumption.
 qed.
 
-(* some problem here: confusion between relations/symmetric 
-and functions/symmetric; functions symmetric is not in 
-functions.moo why?
-theorem symmetric_plus: symmetric nat plus. *)
-
-theorem sym_plus: \forall n,m:nat. plus n m = plus m n.
+theorem sym_plus: \forall n,m:nat. n+m = m+n.
 intros.elim n.
 simplify.apply plus_n_O.
 simplify.rewrite > H.apply plus_n_Sm.
 qed.
 
 theorem associative_plus : associative nat plus.
-simplify.intros.elim x.
+unfold associative.intros.elim x.
 simplify.reflexivity.
 simplify.apply eq_f.assumption.
 qed.
 
-theorem assoc_plus : \forall n,m,p:nat. plus (plus n m) p = plus n (plus m p)
+theorem assoc_plus : \forall n,m,p:nat. (n+m)+p = n+(m+p)
 \def associative_plus.
 
-theorem injective_plus_r: \forall n:nat.injective nat nat (\lambda m.plus n m).
+theorem injective_plus_r: \forall n:nat.injective nat nat (\lambda m.n+m).
 intro.simplify.intros 2.elim n.
 exact H.
 apply H.apply inj_S.apply H1.
 qed.
 
-theorem inj_plus_r: \forall p,n,m:nat. plus p n = plus p m \to n=m
+theorem inj_plus_r: \forall p,n,m:nat. p+n = p+m \to n=m
 \def injective_plus_r.
 
-theorem injective_plus_l: \forall m:nat.injective nat nat (\lambda n.plus n m).
+theorem injective_plus_l: \forall m:nat.injective nat nat (\lambda n.n+m).
 intro.simplify.intros.
-(* qui vorrei applicare injective_plus_r *)
-apply inj_plus_r m.
+apply (injective_plus_r m).
 rewrite < sym_plus.
-rewrite < sym_plus y.
+rewrite < (sym_plus y).
 assumption.
 qed.
 
-theorem inj_plus_l: \forall p,n,m:nat. plus n p = plus m p \to n=m
+theorem inj_plus_l: \forall p,n,m:nat. n+p = m+p \to n=m
 \def injective_plus_l.