Maintaining Consistency in Hierarchical Reasoning

Abstract

We explore techniques for maintaining consistency in reasoning when employing dynamic hierarchical task decompositions. In particular, we consider the difficulty of maintaining consistency when an agent nonmonotonically modifies an assumption in one level of the task hierarchy and that assumption depends upon potentially dynamic assertions higher in the hierarchy. The hypothesis of our work is that reasoning maintenance can be extended to hierarchical systems such that consistency is maintained across all levels of the hierarchy. We introduce two novel extensions to standard reason maintenance approaches, assumption justification and dynamic hierarchical justification, both of which provide the necessary capabilities. The key difference between the two methods is whether a particular assumption (assumption justification) or an entire level of the hierarchy (dynamic hierarchical justification) is disabled when an inconsistency is found. Our investigations suggest that dynamic hierarchi...