Strategies for mixed reasoning with a graph-based reasoning engine

An algorithm is presented that enables a novice to browse through a rule base and to interact with the rule base using a mixed-reasoning strategy. Essentially, the algorithm augments standard forward-reasoning inference with a technique for selecting goals whose antecedents are partially satisfied. The user is asked to confirm or deny the remaining antecedents of these rules. The novelty of the approach lies in the use of graphs as the nodes in combination with a powerful, graph-based inference engine, and in the heuristic for ordering and selecting goals for backward reasoning. The method presented is simple and general, and is easily adapted to any interactive knowledge-based system, owing to the domain independence of the algorithm.