/**
  * Test if this is zero.
  *
  * @return true if this is 0, else false.
  */
 public boolean isZERO() {
   return pol.isZERO();
 }
 /**
  * To String.
  *
  * @return string representation of this.
  */
 @Override
 public String toString() {
   return pol.toString();
 }