...

diff --git a/matita/library/technicalities/setoids.ma b/matita/library/technicalities/setoids.ma
index d730d06de6a60386a43b28c2132dbcdcb0b2568a..c440795ffc2a099ee041fbe8039bc5f20bf478f3 100644 (file)
--- a/matita/library/technicalities/setoids.ma
+++ b/matita/library/technicalities/setoids.ma
@@ -245,7 +245,8 @@ definition equality_morphism_of_symmetric_reflexive_transitive_relation:
     split;
     intro;
     unfold transitive in H;
-    auto
+    unfold symmetric in sym;
+    auto.
   ]
 qed.