On 23.12.2008 08:56, Simon Chiang wrote:
>> Unless there's something more complicated that I am missing, this is a directed, acyclic graph, usually abbreviated as a DAG.
> 
> Ah, great!  I think that's it.
> 
> http://en.wikipedia.org/wiki/Directed_acyclic_graph
> 
> As a followup, does anyone know of libraries that work on DAGs?  I'm
> looking into the Ruby Graph Library, but any recommendations are
> welcome.

The DAG defines a partial order.  You can use it for "topological 
sorting" by stuffing it in a text file formatted suitable to "tsort". 
That tool then will print out nodes in a total ordering that satisfies 
the partial ordering.

Kind regards

	robert