Hello, it is (obviously) correct that hypergraphs are "undirected", since those structures mentioned below are "directed hypergraphs". More substantially, I would strongly warn against considering "directed hypergraphs", if the people involved are not actually doing research in this direction (for some time, that is). There are only a few people considering directed hypergraphs, and it is a research topic (already that the document is from 1992 says something; I'm actually working on the topic, on the connections between hypergraphs and SAT (as in that paper), and thus I would be glad to see something in this direction, but my impression is that the people involved here are not really specialists, but just want to implement something "standard"). Hypergraphs themselves are already such complicated beasts, that I would predict that no useful library can come out of a concept combining "directed hypergraphs" with hypergraphs. Oliver On Thu, Mar 26, 2009 at 06:00:17PM -0400, Andrew Sutton wrote:
IIRC, hypergraphs are only "undirected". An edge is represented as a set of vertices, that is, as an element of the powerset of vertices.
This is incorrect.
http://www.cis.upenn.edu/~lhuang3/wpe2/papers/gallo92directed.pdf
Andrew Sutton andrew.n.sutton@gmail.com _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
-- Dr. Oliver Kullmann Computer Science Department Swansea University Faraday Building, Singleton Park Swansea SA2 8PP, UK http://cs.swan.ac.uk/~csoliver/