Abstract: Searching AND/OR graph is an important problem-solving technique in the area of artificial intelligence. The representation of AND/OR graph based on traditional data structures greatly limits the scale of the graph that could be handled with existing AND/OR graph searching algorithm. Based on the symbolic representation of acyclic AND/OR graph using 0BDD(ordered binary decision diagram)，we proposed a novel symbolic algorithm for searching minimal-cost solution graph of acyclic AND/OR graph. It is shown that the symbolic algorithm has lower space complexity and can be used to handle larger-scale acyclic AND/OR graphs.

Key words: AND/OR graph, Minimal-cost solution graph, OBDDs