Hi I've a problem whit "put" function. My simple code is: -------------------------- typedef Is_finite<Triangulation> Filter; typedef boost::filtered_graph<Triangulation,Filter,Filter> Finite_triangulation; typedef boost::graph_traits<Finite_triangulation>::vertex_descriptor vertex_descriptor; typedef boost::graph_traits<Finite_triangulation>::vertex_iterator vertex_iterator; typedef boost::graph_traits<Finite_triangulation>::edge_descriptor edge_descriptor; typedef boost::graph_traits<Finite_triangulation>::edge_iterator edge_iterator; int main(int,char*[]) { Triangulation t; Filter is_finite(t); Finite_triangulation ft(t, is_finite, is_finite); //graph t.insert(Point(0.4, 1)); t.insert(Point(1, 0.3)); t.insert(Point(0.0, -0.9)); t.insert(Point(-1, 0)); t.insert(Point(1, 2)); boost::property_map<Triangulation,boost::edge_weight_t>::type weight_map=get(boost::edge_weight,ft); edge_iterator eit,eend; for (boost::tie(eit,eend)=boost::edges(ft); eit!=eend; ++eit) { std::cout << "PESO: " << get(weight_map,*eit) << "\n"; put(weight_map,*eit ,100); std::cout << "PESO2: " << get(weight_map,*eit) << "\n"; } return 0; } ------ at compile time I've: "/property_map.hpp:319: error: invalid lvalue in assignment" Why get is right and put no??Can help me?? Best regards -Bombielfil-