I figured it out myself: template<typename CDB, typename CDB1> struct CTargetEqualOrGreater { typedef CTargetEqualOrGreater<CDB, CDB1> type; typedef typename boost::mpl::transform< CDB, CDB1, boost::mpl::not_< boost::mpl::or_< boost::mpl::and_< boost::mpl::not_<boost::mpl::_1>, boost::mpl::not_<boost::mpl::_2> >, boost::mpl::_1 > > >::type CBoolVector; typedef typename boost::mpl::max_element<CBoolVector>::type CMaxElement; typedef typename boost::mpl::deref<CMaxElement>::type CDeRef; static const bool value = CDeRef::value == false; }; -----Original Message----- From: FOELSCHE,PETER (A-SantaClara,ex1) Sent: Tuesday, September 30, 2008 11:53 To: 'boost-users@lists.boost.org' Subject: [Boost-users] boost::mpl::max_element and boost::mpl::vector I have two vectors (CDB and CDB1) containing boolean. I want to make certain that if a bit in the second vector is set, it must also be set in the first vector. template<typename CDB, typename CDB1> struct CTargetEqualOrGreater { static const bool value = boost::mpl::deref< boost::mpl::max_element< boost::mpl::transform< CDB, CDB1, boost::mpl::not_< boost::mpl::or_< boost::mpl::and_< boost::mpl::not_<boost::mpl::_1>, boost::mpl::not_<boost::mpl::_2> >, boost::mpl::_1 > > > > >::type::value == 0; }; ... BOOST_MPL_ASSERT( (CTargetEqualOrGreater<CDB, CDB1>::value)); But this does not compile.