Given a template class like

template < typename T > struct A
{
  template < typename U > friend bool operator == ( const A &, const U & );
  template < typename U > friend bool operator == ( const U &, const A & );
  template < typename U > friend bool operator != ( const A &, const U & );
  template < typename U > friend bool operator != ( const U &, const A & );
  // ...other stuff...
};

can I express it using equality_comparable?

Thanks, Rob.