Relevance in Belief Update

It has been pointed out by Katsuno and Mendelzon that the so-called AGM revision operators, defined Alchourrón, Gärdenfors Makinson, do not behave well in dynamically-changing applications. On premise, formally characterized a different type of belief-change typically referred to as KM update which, this date, constitute benchmark belief update. In article, we show there exist operators yield same counter-intuitive results any operator. Against non-satisfactory background, prove translation Parikh’s relevance-sensitive axiom (P), realm update, suffices block liberal behaviour operators. is shown, both axiomatically semantically, (P) for essentially, encodes relevance acts at possible-worlds level, context which each possible world locally modified, light new information. Interestingly, level shown be equivalent form sentential considering building blocks sentences language. Furthermore, concretely demonstrate notion can regarded (at least partial) solution frame, ramification qualification problems, encountered worlds. Last but least, whole class well-behaved, introduced, generalize Forbus’ operator are perfectly-suited real-world implementations.