X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fmatita%2Fnlibrary%2Fdatatypes%2Flist-theory.ma;h=4957feed26ac57e4c219b740eab7dd85f79ff3d2;hb=89fc31fc5cc01e8860cf67a8e096c24125370d31;hp=14bab26e31558989a2fa8ef3075138d1bf4b8977;hpb=4b940bfbeab1181dd18c56e46761f5e6690d9f9d;p=helm.git

diff --git a/helm/software/matita/nlibrary/datatypes/list-theory.ma b/helm/software/matita/nlibrary/datatypes/list-theory.ma
index 14bab26e3..4957feed2 100644
--- a/helm/software/matita/nlibrary/datatypes/list-theory.ma
+++ b/helm/software/matita/nlibrary/datatypes/list-theory.ma
@@ -20,7 +20,7 @@ ntheorem nil_cons:
 #A;#l;#a; @; #H; ndestruct;
 nqed.
 
-ntheorem append_nil: ∀A:Type.∀l:list A.l @ □ = l.
+ntheorem append_nil: ∀A:Type.∀l:list A.l @ [ ] = l.
 #A;#l;nelim l;//;
 #a;#l1;#IH;nnormalize;//;
 nqed.