@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;
  }

    @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;
  }

    @Override
    public int hashCode() {
      return System.identityHashCode(this);
    }

    @Override
    public String toString() {
      return "-\u221e";
    }

    private Object readResolve() {
      return INSTANCE;
    }

    private static final long serialVersionUID = 0;
  }

  /*
   * The implementation neither produces nor consumes any non-null instance of

    final EnumSet<E> delegate;

    EnumSerializedForm(EnumSet<E> delegate) {
      this.delegate = delegate;
    }

    Object readResolve() {
      // EJ2 #76: Write readObject() methods defensively.
      return new ImmutableEnumSet<E>(delegate.clone());
    }

    private static final long serialVersionUID = 0;
  }

    @Override
    public int hashCode() {
      return System.identityHashCode(this);
    }

    @Override
    public String toString() {
      return "-\u221e";
    }

    private Object readResolve() {
      return INSTANCE;
    }

    private static final long serialVersionUID = 0;
  }

  /*
   * The implementation neither produces nor consumes any non-null instance of

    final EnumSet<E> delegate;

    EnumSerializedForm(EnumSet<E> delegate) {
      this.delegate = delegate;
    }

    Object readResolve() {
      // EJ2 #76: Write readObject() methods defensively.
      return new ImmutableEnumSet<E>(delegate.clone());
    }

    private static final long serialVersionUID = 0;
  }

    protected boolean doEquivalent(Object a, Object b) {
      return a.equals(b);
    }

    @Override
    protected int doHash(Object o) {
      return o.hashCode();
    }

    private Object readResolve() {
      return INSTANCE;
    }

    private static final long serialVersionUID = 1;
  }

  static final class Identity extends Equivalence<Object> implements Serializable {

    protected boolean doEquivalent(Object a, Object b) {
      return a.equals(b);
    }

    @Override
    protected int doHash(Object o) {
      return o.hashCode();
    }

    private Object readResolve() {
      return INSTANCE;
    }

    private static final long serialVersionUID = 1;
  }

  static final class Identity extends Equivalence<Object> implements Serializable {

    public int compareTo(Object o) {
      return toString().compareTo(o.toString());
    }

    @Override
    public String toString() {
      return "BY_TO_STRING";
    }

    private Object readResolve() {
      return INSTANCE;
    }
  }

  // Always equal is a valid total ordering. And it works for any Object.
  private static final class AlwaysEqual extends Ordering<@Nullable Object>

    public int compareTo(Object o) {
      return toString().compareTo(o.toString());
    }

    @Override
    public String toString() {
      return "BY_TO_STRING";
    }

    private Object readResolve() {
      return INSTANCE;
    }
  }

  // Always equal is a valid total ordering. And it works for any Object.
  private static final class AlwaysEqual extends Ordering<@Nullable Object>