Boost C++ Libraries

namespace boost {
  namespace icl {
    template<typename Integral> struct is_numeric<boost::rational< Integral >>;
    template<typename Integral> 
      struct is_continuous<boost::rational< Integral >>;
    template<typename Integral> struct is_discrete<boost::rational< Integral >>;
    template<typename Integral> struct has_inverse<boost::rational< Integral >>;
  }
}