diff --git a/gap/structure.gi b/gap/structure.gi
index 3013796..f033c3d 100644
--- a/gap/structure.gi
+++ b/gap/structure.gi
@@ -527,7 +527,7 @@ RoughJoinOfFilters@ := function(list, first)
   local item, jof;
   jof := Set(FiltersOfObj@(first));
   for item in list{[2..Length(list)]} do
-    IntersectSet(jof, FiltersOfObj@);
+    IntersectSet(jof, FiltersOfObj@(item));
   od;
 end;