Bonjour Dear I want to check whether there is a directed path between two given nodes (A and C) using Boost graph. I also want to access intermediate edges to examine PDAG properties. I test void transitive_closure(const Graph& g, GraphTC& tc) method. But i want to check between two given nodes. Now i want to ask you - void transitive_closure(const Graph& g, GraphTC& tc, G_to_TC_VertexMap g_to_tc_map, VertexIndexMap index_map) In the above method, how i can declare G_to_TC_VertexMap g_to_tc_map, VertexIndexMap index_map? http://www.boost.org/doc/libs/1_39_0/libs/graph/doc/transitive_closure.html - How i can examine the intermediate edges? or is there any other easy way? I will be thankful to you Best Regards Amanullah YASIN Master2 (ECD) Ecole Polytechnique Université de Nantes, France. Mob# 06 47 62 89 96 Fix # 02 72 00 26 45 amanyasin@gmail.com