X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fmatita%2Flibrary%2Fnat%2Fminus.ma;h=10d218d440d7194f2d10e127fddcc3f9eadff05e;hb=b58b7f9f3fdf8d66522b31828faa5bfa588c31b8;hp=a0133e93db58f65df22e64ca4e94944a26fda79e;hpb=dc0aa21dae28cd07142cb7bcaf8e6a1bfd99018d;p=helm.git

diff --git a/helm/software/matita/library/nat/minus.ma b/helm/software/matita/library/nat/minus.ma
index a0133e93d..10d218d44 100644
--- a/helm/software/matita/library/nat/minus.ma
+++ b/helm/software/matita/library/nat/minus.ma
@@ -76,13 +76,12 @@ qed.
 
 theorem minus_plus_m_m: \forall n,m:nat.n = (n+m)-m.
 intros 2.
-generalize in match n.
-elim m.
+elim m in n ⊢ %.
 rewrite < minus_n_O.apply plus_n_O.
-elim n2.simplify.
+elim n1.simplify.
 apply minus_n_n.
 rewrite < plus_n_Sm.
-change with (S n3 = (S n3 + n1)-n1).
+change with (S n2 = (S n2 + n)-n).
 apply H.
 qed.