A parametric definition for a family of inheritance reasoners

This paper gives a declarative specification of a popular inheritance system and shows how simple changes to this specification can result in different path-based reasoners. This parameterized definition provides a deeper understanding of the fundamental differences between some of the more popular path-based inheritance reasoners. In particular, it allows the clarification of some of the results on the complexity of reasoning in the various systems. The uniform framework also allows definition of novel systems which constitute intermediate points in the space of possible reasoners, and facilitates perspicuous Prolog implementation. The work reported here is primarily the research of Carl Vogel, with Fred Popowich being particularly involved with the initial logical specification and implementation. Thanks to Nick Cercone, who collaborated with the authors on earlier research relating to the material presented in this paper, and also to two anonymous reviewers for constructive suggestions. Vogel is particularly grateful to Robin Cooper and Jeff Pelletier for feedback and encouragement as well as to the Marshall Aid Commemoration Commission for making it possible for him to do his Ph. D. at the Centre for Cognitive Science in Edinburgh. Popowich wishes to acknowledge the support of the Natural Sciences and Engineering Research Council of Canada. Carl Vogel, Ph.D.: He is a Research Scientist in the Institute for Computational Linguistics at the University of Stuttgart. He is grateful to the Sonderforshungsbereich 340 for funding his postdoctoral work there. Vogel finished his Ph.D. in Cognitive Science at the University of Edinburgh in 1995. He is interested in the proof theory and semantics of default reasoning as well as consequent applications throughout computational linguistics: semantics of natural language generics, robust processing of natural language in typed feature systems, and syntactic representation. Fred Popowich, Ph.D.: He is an Associate Professor of Computing Science and an Associate Member of the Department of Linguistics at Simon Fraser University. He received his Ph.D. in Cognitive Science/ Artificial Intelligence from the University of Edinburgh in 1989. His current research interests include the development and processing of unification based grammars, machine translation, natural language interfaces to databases, the structure of the lexicon, the use of inheritance in the lexicon, and the use of lexical resources in natural language processing applications.