Trying to use bundled properties like so. typedef std::string Colour; struct edge_properties { string eName; set< Colour > Colours; }; Then the following works OUTSIDE the vis object. graph_t::edge_descriptor e = *edges(g).first; g[e].Colours.insert("5ty"); g[e].Colours.insert("6"); g[e].Colours.insert("7"); set<Colour> set(g[e].Colours); for(std::set<Colour>::iterator si = set.begin(); si != set.end(); si++) std::cout << *si << " "; But if I try to use edge property.Colours INSIDE the vis object (using maps or not) like so. typedef set< string > Set; for(colour_iter=Colour.begin(); colour_iter != Colour.end(); ++colour_iter) { //Set & set = get(m_eColours_map, e); get(m_eColours_map, e).insert( *colour_iter ); //set.insert( *colour_iter ); //g[e].Colours; //g[e].Colours.insert("Green"); //g[e].Colours.insert(*colour_iter); //g[e].Colours.insert("5"); //g[e].Colours.end(); } It compiles but gives Segmentation fault no matter what I try. Im beginning to think that set< string > will not work inside the vis object. If thats true I'll have to rewrite a major part of my program, but I hope not. Using : BOOST_LIB_VERSION "1_36" Thanks Caligula