I've supplied patches to the following header files: <boost/concept_check.hpp> <boost/concept/detail/concept_def.hpp> <boost/graph/graph_concepts.hpp> Basically I used the constructor fix already present in the Graph concept checking class definition and applied it in the definitions of all the other concept checking classes. Everything works as expected now when the patches are applied. Feel free to improve on them, of course. Cromwell D. Enage __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com