public boolean is_superset_of(terminal_set other) throws internal_error {
  not_null(other);
  return other.is_subset_of(this);
}

public boolean is_superset_of ( terminal_set other ) throws internal_error { not_null ( other ) ; return other . is_subset_of ( this ) ; }
determine if this set is an ( improper ) superset of another .
