More on Inheritance Hierarchies with Exceptions: Default Theories and Inferential Distance

David W. Etherington

In Artificial Intelligence, well-understood reasoning systems and tractable reasoning systems have often seemed mutually exclusive. This has been exemplified by nonmonotonic reasoning formalisms and inheritance-with-exceptions reasoners. These have epitomized the two extremes: the former not even semidecidable, the latter completely ad hoc. We previously presented a formal mechanism for specifying inheritance systems, and minimal criteria for acceptable inheritance reasoning. This left open the problem of realizing an acceptable reasoner. Since then, Touretzky has developed a reasoner that appears to meet our criteria. We show that his reasoner is formally adequate, and explore some of the implications of this result vis-a-vis the study of nonmonotonic reasoning.

This page is copyrighted by AAAI. All rights reserved. Your use of this site constitutes acceptance of all of AAAI's terms and conditions and privacy policy.