  typename EK::Plane_3 read_plane_impl(std::istream& in, Compose_) {
    typedef Fraction_traits<typename K::FT> FracTraits;
    typename FracTraits::Type a, b, c, d;
    typename FracTraits::Numerator_type num;
    typename FracTraits::Denominator_type denom(1);
    typename FracTraits::Compose composer;
    in >> num;
    a = composer(num, denom);
    in >> num;
    b = composer(num, denom);
    in >> num;
    c = composer(num, denom);
    in >> num;
    d = composer(num, denom);
    return typename EK::Plane_3(a,b,c,d);
  }
  typename EK::Plane_3 read_plane_impl(std::istream& in, Compose_) {
    typedef Fraction_traits<typename K::FT> FracTraits;
    typename FracTraits::Type a, b, c, d;
    typename FracTraits::Numerator_type num;
    typename FracTraits::Denominator_type denom(1);
    typename FracTraits::Compose composer;
    in >> num;
    a = composer(num, denom);
    in >> num;
    b = composer(num, denom);
    in >> num;
    c = composer(num, denom);
    in >> num;
    d = composer(num, denom);
    return typename EK::Plane_3(a,b,c,d);
  }