Because there has been continuing concern about the algorithm, I looked up more information in the standard textbook I referred to in an earlier email (Cormen, Leiserson, and Rivest).
The Floyd-Warshall algorithm (so named because the algorithm was proposed by Floyd but based on a theorem by Warshall) works on any closed semiring. A semiring is defined by two operations (which I called min and + in my earlier mail). For computing beatpaths, the operations are max and min respectively. Showing that max and min define a semiring, and that the required closure properties hold, is straightforward. I refer those who are interested to the text above. -- Andrew ---- Election-methods mailing list - see http://electorama.com/em for list info
