[Boost-users] [operators] equality_comparable

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.