* @since 15.0
   */
  public static DiscreteDomain<BigInteger> bigIntegers() {
    return BigIntegerDomain.INSTANCE;
  }

  private static final class BigIntegerDomain extends DiscreteDomain<BigInteger>
      implements Serializable {
    private static final BigIntegerDomain INSTANCE = new BigIntegerDomain();

    BigIntegerDomain() {
      super(true);
    }

   * @since 15.0
   */
  public static DiscreteDomain<BigInteger> bigIntegers() {
    return BigIntegerDomain.INSTANCE;
  }

  private static final class BigIntegerDomain extends DiscreteDomain<BigInteger>
      implements Serializable {
    private static final BigIntegerDomain INSTANCE = new BigIntegerDomain();

    BigIntegerDomain() {
      super(true);
    }