AAAI Publications, Sixteenth International Conference on Principles of Knowledge Representation and Reasoning

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Incorporating Relevance in Epistemic States in Belief Revision
James Delgrande, Pavlos Peppas

Last modified: 2018-09-24


We present an account of relevance in belief revision where, intuitively, one wants to only consider the relevant part of an agent's epistemic state in a revision. We assume that relevance is a domain-specific notion, and that (ir)relevance assertions are given as part of the agent's epistemic state. Such assertions apply in a given context, and are of the form ``in the case that formula \sigma holds, the Y part of the agent's epistemic state is independent of the rest of the epistemic state'', where Y is part of the signature of the language. Two approaches are given, one in which (in semantic terms) conditions are placed on a faithful ranking on possible worlds to enforce the (ir)relevance assertions, and a second in which the possible worlds characterising the agent's beliefs may be modified in a revision. These approaches are shown to yield the same resulting belief set. Corresponding postulates and a representation result are given. The overall approach is compared to that of Parikh's for language splitting as well as with multivalued dependencies in relational databases.


Knowledge representation and reasoning; belief revision; relevance

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