X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fmatita%2Flibrary%2FZ%2Ftimes.ma;h=979cc87aa37f8ddbebe67e2273cc42a48a894f76;hb=0c00c81d91748e89757711eb13ded4227e079ac9;hp=90a71b520ff3fde852bb2026812af9beea519cbe;hpb=f262223fb7b49a191b25d27ecc58818b9d7a357d;p=helm.git

diff --git a/helm/software/matita/library/Z/times.ma b/helm/software/matita/library/Z/times.ma
index 90a71b520..979cc87aa 100644
--- a/helm/software/matita/library/Z/times.ma
+++ b/helm/software/matita/library/Z/times.ma
@@ -12,8 +12,6 @@
 (*                                                                        *)
 (**************************************************************************)
 
-set "baseuri" "cic:/matita/Z/times".
-
 include "nat/lt_arith.ma".
 include "Z/plus.ma".
 
@@ -251,3 +249,13 @@ qed.
 variant distr_Ztimes_Zplus: \forall x,y,z.
 x * (y + z) = x*y + x*z \def
 distributive_Ztimes_Zplus.
+
+theorem eq_plus_Zplus: \forall n,m:nat. Z_of_nat (n+m) =
+Z_of_nat n + Z_of_nat m.
+intro.cases n;intro
+  [reflexivity
+  |cases m
+    [simplify.rewrite < plus_n_O.reflexivity
+    |simplify.reflexivity.
+    ]]
+qed.