Ian Frank, Electrotechnical Laboratory; David Basin, Universität Freiburg; Alan Bundy, University of Edinburgh
In problem solving, it is often important not only to find a solution but also to be able to explain it. We use the game of Bridge to illustrate how tactics, which formalise domain-specific expertise, can be used for both these tasks. Our Bridge tactics constrain search to the point where optimal strategies can be identified, and also provide the key to explaining these strategies in human-understandable terms. We demonstrate this by solving, in the technical sense, a canonical set of single-suit Bridge problems from a definitive expert text: in addition to always finding optimal solutions (and revealing a 3% error rate in the expert answers), each solution is automatically explained in language comparable to that of the expert text.