How to use template parameter class on virtual methods?

I know that is not possible to use template on virtual method, because the compile there is no way to know how to implement all possibilities, but what I need is to use template on a restricted way, like that:

template<typename T, size_t N>
class MatBase {
 public:
  static constexpr size_t order = N;

  using value_type = T;

  MatBase() = default;
  virtual ~MatBase() = default;

  template<class Fn = T(T)>
  virtual void Map(Fn&& fn) = 0;

  template<class Fn = T(T,T)>
  virtual T Reduce(Fn&& fn) = 0;
};

It means, Fn uses the template declared on class, so I think it is possible to compiler infer all possible types. Are there way to do something like that C++?