public boolean is_subset_of(symbol_set other) throws internal_error {
  not_null(other);
  for (Enumeration e=all(); e.hasMoreElements(); )   if (!other.contains((symbol)e.nextElement()))   return false;
  return true;
}

public boolean is_subset_of ( symbol_set other ) throws internal_error { not_null ( other ) ; for ( Enumeration e = all ( ) ; e . hasMoreElements ( ) ; ) if ( ! other . contains ( ( symbol ) e . nextElement ( ) ) ) return false ; return true ; }
determine if this set is an ( improper ) subset of another .
