Updating and Structure in Non-Monotonic Theories (PhD Dissertation 1992, Stanford & IBM)

Pragmatic reasoning often involves conflict about beliefs with some degree of plausibility, e.g., overridable rules (defaults). However, conflict (i.e., logical non-monotonicity) can require impractical (i.e., intractable) computational effort. We attack the problem at a logical level, choosing the circumscription formalism as our vehicle of analysis for its mathematical convenience and expressive power. We give a new divide-and-conquer strategy for coping with the challenges of scale, based on new concepts of decomposition and of truth maintenance. We show new general- and special-case results about how to localize updating and belief revision, forward and backward inferencing, and specification. Many of the special cases can be recognized syntactically, and thus are computationally tractable. In addition, we employ a new, more-general concept of prioritization.

By: Benjamin N. Grosof

Published in: RC20683 in 1997


This Research Report is available. This report has been submitted for publication outside of IBM and will probably be copyrighted if accepted for publication. It has been issued as a Research Report for early dissemination of its contents. In view of the transfer of copyright to the outside publisher, its distribution outside of IBM prior to publication should be limited to peer communications and specific requests. After outside publication, requests should be filled only by reprints or legally obtained copies of the article (e.g., payment of royalties). I have read and understand this notice and am a member of the scientific community outside or inside of IBM seeking a single copy only.


Questions about this service can be mailed to reports@us.ibm.com .