LOCAL
      x : SET  OF  presentation_representation_relationship;
      local_children : SET OF presentation_representation;
    END_LOCAL;

    REPEAT  i:=1 TO  HIINDEX(children);
      IF  relation\representation_relationship.rep_1 :=: children[i] THEN
        RETURN(FALSE);
      END_IF;
    END_REPEAT;

    x := bag_to_set (USEDIN ( relation\representation_relationship.rep_1,
                  'REPRESENTATION_SCHEMA.'+
                  'REPRESENTATION_RELATIONSHIP.REP_2'));
    local_children := children + relation\representation_relationship.rep_1;

    IF  SIZEOF (x) > 0 THEN
      REPEAT i:=1 TO HIINDEX (x);
        IF NOT acyclic_presentation_representation_relationship
          (x[i] , local_children) THEN
          RETURN  (FALSE);
        END_IF;
      END_REPEAT;
    END_IF;

    RETURN (TRUE);