operator-(const RScalar<T1>& l, const RComplex<T2>& r)
operator-(const RComplex<T1>& l)
operator-(const RScalar<T1>& l, const RComplex<T2>& r){  typedef typename BinaryReturn<RScalar<T1>, RComplex<T2>, OpSubtract>::Type_t  Ret_t;  return Ret_t(l.elem() - r.real(),	       l.elem() - r.imag());}