In Hobbs, J. R. and Moore, R. C. (Eds.), Formal Theories of the Commonsense World, chap. 2, pp. 37–70. Ablex

IEEE Transactions on Software Engineering, 11:1321-36

Proceedings, 23rd Annual Meeting of the Association for Computational Linguistics, pp. 61-69. Chicago, Illinois, July 1985.

The complexities of various search algorithms are considered in terms of time, space, and cost of solution path. It is known that breadth-first search requires too much space and depth-first search can use too much time and doesn't always find a cheapest path. A depth-first iterative-deepening algorithm is shown to be asymptotically optimal along all three dimensions for exponential tree searches. The algorithm has been used successfully in chess programs, has been effectively combined with bi-directional search, and has been applied to best-first heuristic search as well. This heuristic depth-first iterative-deepening algorithm is the only known algorithm that is capable of finding optimal solutions to randomly generated instances of the Fifteen Puzzle within practical resource limits.

Artificial Intelligence 24:7—83. Reprinted In Hobbs, J. R. and Moore, R. C. (Eds.), Formal Theories of the Commonsense World, chap. 4, pp. 109–183. Ablex.

Cognitive Science: A Multidisciplinary Journal, Vol 9, No. 2, pp. 171-216, 1985

Artificial Intelligence, 27, 183–217.

Proc. Third Alvey IKBS SIG Workshop

Artificial Intelligence 26:251-321

Cambridge, Mass.: MIT Press