Ok, I fixed some of my mistakes but it now appears the overloaded operators aren't being seen so I must be missing another header or something. Once again here's the code compiled under VS.NET, debug, boost version 1_29_0, with the resultant error messages following. #include <iostream> #include <boost/numeric/ublas/matrix.hpp> #include <boost/numeric/ublas/matrix_expression.hpp> int main() { using namespace boost::numeric::ublas; matrix<double> m1(3, 3), m2(3, 3); for(unsigned int i = 0; i < std::min(m1.size1(), m2.size1()); ++i) for(unsigned int j = 0; j < std::min(m1.size2(), m2.size2()); ++j) m1(i, j) = m2(i, j) = 3 * i + j; std::cout << m1 + m2 << std::endl; std::cout << m1 - m2 << std::endl; std::cin.get(); return EXIT_SUCCESS; } c:\Documents and Settings\Agiato\My Documents\Visual Studio Projects\test5\matrixAddSub.cpp(15): error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'boost::numeric::ublas::matrix_binary_traits<E1,E2,F>::result_ty pe' (or there is no acceptable conversion) with [ E1=boost::numeric::ublas::matrix<double,boost::numeric::ublas::row_ma jor,boost::numeric::ublas::unbounded_array<double>>, E2=boost::numeric::ublas::matrix<double,boost::numeric::ublas::row_ma jor,boost::numeric::ublas::unbounded_array<double>>, F=boost::numeric::ublas::scalar_plus<boost::numeric::ublas::matrix<do uble,boost::numeric::ublas::row_major,boost::numeric::ublas::unbounde d_array<double>>::value_type,boost::numeric::ublas::matrix<double,boo st::numeric::ublas::row_major,boost::numeric::ublas::unbounded_array< double>>::value_type> ] c:\Documents and Settings\Agiato\My Documents\Visual Studio Projects\test5\matrixAddSub.cpp(17): error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'boost::numeric::ublas::matrix_binary_traits<E1,E2,F>::result_ty pe' (or there is no acceptable conversion) with [ E1=boost::numeric::ublas::matrix<double,boost::numeric::ublas::row_ma jor,boost::numeric::ublas::unbounded_array<double>>, E2=boost::numeric::ublas::matrix<double,boost::numeric::ublas::row_ma jor,boost::numeric::ublas::unbounded_array<double>>, F=boost::numeric::ublas::scalar_minus<boost::numeric::ublas::matrix<d ouble,boost::numeric::ublas::row_major,boost::numeric::ublas::unbound ed_array<double>>::value_type,boost::numeric::ublas::matrix<double,bo ost::numeric::ublas::row_major,boost::numeric::ublas::unbounded_array <double>>::value_type> ] Thanks to all for their help! Jon Agiato JonAgiato@nyc.rr.com