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Default logic: Orderings and extensions

  • Mike Hopkins
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 747)

Abstract

An ordering on default rules is defined that formalises intuitive relationships between rules. Unlike Etherington's [Eth88] orderings on literals which were only used to guarantee the existence of a computable extension, ours are defined proof-theoretically and used as an integral part of an algorithm that efficiently calculates all extensions for several useful sub-classes of default logic. The algorithm represents a significant reduction in complexity over other existing methods, especially for large multi-domain examples where indepeneant partial extensions can be calculated for different groups of unrelated rules which can be combined to produce complete extensions. Also, by changing the definition of the orderings without altering the underlying algorithm, extensions can be calculated for variants of default logic that have been proposed since Reiter's original paper.

Keywords

Network Theory Rule Application Extension Calculation Default Rule Default Theory 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

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Copyright information

© Springer-Verlag Berlin Heidelberg 1993

Authors and Affiliations

  • Mike Hopkins
    • 1
  1. 1.Department of Computer Science, Queen Mary and Westfield CollegeUniversity of LondonUK

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