Dear James Green-Armytage, let's say that there are 4 candidates.
When you add a ballot and its inverted ballot then each entry of the pairwise matrix is increased by 1. Let's say that you want to increase the entry B:E. Then you can simply add a ballot where B and E are ranked in an adjacent manner and its inverted ballot. When you then switch the positions of B and E in the inverted ballot, then the entry B:E is increased by 2, the entry E:B is increased by 0, and every other entry is increased by 1. Example: Suppose you want to increase the entry B:E without changing the other entries relatively to each other. When you add the ballots B>E>A>D and D>A>E>B then each entry is increased by 1. Therefore, when you add B>E>A>D and D>A>B>E then you increase the strength of the pairwise defeat B:E without changing the strengths of the other pairwise defeats relatively to each other. With this method, it is possible to create successively any matrix of pairwise defeats (as long as you are interested only in the directions and the margins of the pairwise defeats). This method has been proposed by Blake Cretney a few years ago. Markus Schulze ---- Election-methods mailing list - see http://electorama.com/em for list info
