@Override
    public Integer minValue() {
      return Integer.MIN_VALUE;
    }

    @Override
    public Integer maxValue() {
      return Integer.MAX_VALUE;
    }

    private Object readResolve() {
      return INSTANCE;
    }

    @Override
    public String toString() {
      return "DiscreteDomain.integers()";
    }

    private static final long serialVersionUID = 0;
  }