Katsuno and Mendelzon have distinguished two abstract frameworks for reasoning about change: theory revision and theory update. Theory re- vision involves a change in knowledge or belief with respect to a static world. By contrast, theory update involves a change of knowledge or belief in a changing world. In this paper we are concerned with theory update. Winslett has shown that theory update should be computed "one model at a time." Accordingly, we focus exclusively on update of interpretations. We begin with a study of revision programming , introduced by Marek and Truszczynski to formalize interpretation update in a language similar to logic programming. While revision programs provide a useful and natural de nition of interpretation update, they are limited to a fairly restricted set of update rules. Accordingly, we introduce the more general notion of rule update - interpretation update by arbitrary sets of inference rules. We show that Winslett's approach to update by means of arbitrary sets of formulae corresponds to a simple subclass of rule update. We also specify a simple embedding of rule update in Reiter's default logic , obtained by augmenting the original update rules with default rules encoding the commonsense law of inertia | the principle that things change only when they are made to.

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Journal of Logic Programming, Vol. 30, 2 (1997), pp. 125-143.

@article{prz97, title={Update by Means of Inference Rules}, author={Teodor Przymusinski and Hudson Turner}, volume={30}, journal={Journal of Logic Programming}, number={2}, pages={125-143}, url="http://www.cs.utexas.edu/users/ai-lab?prz97", year={1997} }