I'm working with something as follows. A graph consists of a set of vertices and a set of edges. vertices are connected to edges through a seperate datastructure. This allows data to be attached to vertices, edges, and the connection between a vertex and edge. As for as multilevel hypergraphs go. It essentially allows the graph to be partitioned into multiple smaller graphs. ie: a 100,000 node graph is partitioned into a graph with 1000 nodes, then the 1000 node graph is partitioned into a 10 node graph. The graph can be walked at each level, and you can move to a higher or lower level. This is somewhat like subgraph in the current BGL. I'll try to get a skeleton prototype, and a short design document put together so I can get some feedback. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com