There appears to be a typo in transitive_reduction.hpp where a semicolon should be a comma. Cheers, Shaun --- graph/transitive_reduction.hpp (revision 68995) +++ graph/transitive_reduction.hpp (working copy) @@ -99,7 +99,7 @@ transitive_reduction(const Graph& g, Gra { //and run through all vertices in topological order typename std::vector<Vertex>::reverse_iterator - rit = topo_order.rbegin(); + rit = topo_order.rbegin(), rend = topo_order.rend(); for(; rit != rend; ++rit ) { //looking if they are successors of *it