A general heuristic bottom-up procedure for searching and/or graphs

This paper presents a general heuristic bottom-up procedure for finding a least-cost solution tree of an AND/OR graph when the cost functions associated with the arcs are monotone. Since monotone cost functions are very general, the procedure is applicable to a very large number of problems. The procedure works for both cyclic and acyclic AND/OR graphs, and subsumes most of the known bottom-up procedures for searching AND/OR graphs. Many state-space search procedures and dynamic programming procedures are also special cases of this procedure.