diff --git a/gap/structure.gi b/gap/structure.gi
index 905813b..38a114d 100644
--- a/gap/structure.gi
+++ b/gap/structure.gi
@@ -512,7 +512,7 @@ FiltersOfObj@ := function(obj)
   local f;
   f := CategoriesOfObject(obj);
   Append(f,KnownTruePropertiesOfObject(obj));
-  Append(f,List(KnownAttributesOfObject(obj), x -> Concatenate("Has", x)));
+  Append(f,List(KnownAttributesOfObject(obj), x -> Concatenation("Has", x)));
   return f;
 end;
 
@@ -523,7 +523,7 @@ end;
 # This is a helper that creates a rough join of the filters of a list of
 # objects, using the same arguments as directproduct op (the redundant "first"
 # argument, which is handy for seeding the filter list)
-RoughJoinOfFilters@ := function(list, first);
+RoughJoinOfFilters@ := function(list, first)
   local item, jof;
   jof := Set(FiltersOfObj@(first));
   for item in list{[2..Length(list)]} do