I have a Graph type which satisfies concepts: boost::function_requires<boost::GraphConcept<Graph> >(); boost::function_requires<boost::IncidenceGraphConcept<Graph> >(); boost::function_requires<boost::BidirectionalGraphConcept<Graph> >(); boost::function_requires<boost::VertexListGraphConcept<Graph> >(); boost::function_requires<boost::AdjacencyGraphConcept<Graph> >(); when i make a reverse adaptor: boost::make_reverse_graph(g); i receive such errors: 'edges_size_type' : is not a member of 'boost::graph_traits<Graph>' 'edge_property_type' : is not a member of 'Graph' 'vertex_property_type' : is not a member of 'Graph' Why does reverse_graph requires edges_size_type? edges_size_type isn't in BidirectionalGraph, VertexListGraph, PropertyGraph. it is in EdgeListGraph. reverse_graph requires Graph to be `BidirectionalGraph and optionally VertexListGraph and PropertyGraph`. What does `optionally` mean? My graph is not a PropertyGraph. I want just revert edges. -- Regards, Andrey