X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fmatita%2Flibrary%2Fnat%2Fcount.ma;h=73e251bf6b35929353622914eb364e393ad85a5f;hb=4dc47c9675ffd5fa50296ffaa9b5997501518c98;hp=6b5dbbe660f4b23a9253a55e90832552ccae2fba;hpb=c445ba5534cccde19016c92660ab52777af221c0;p=helm.git

diff --git a/helm/software/matita/library/nat/count.ma b/helm/software/matita/library/nat/count.ma
index 6b5dbbe66..73e251bf6 100644
--- a/helm/software/matita/library/nat/count.ma
+++ b/helm/software/matita/library/nat/count.ma
@@ -33,7 +33,7 @@ theorem sigma_plus: \forall n,p,m:nat.\forall f:nat \to nat.
 sigma (S (p+n)) f m = sigma p (\lambda x.(f ((S n) + x))) m + sigma n f m.
 intros. elim p.
 simplify.
-rewrite < (sym_plus n m).reflexivity.
+reflexivity.
 simplify.
 rewrite > assoc_plus in \vdash (? ? ? %).
 rewrite < H.