Computing MPMA updates using Dijkstra’s semantics
We describe a generalization of the PMA, called the modified PMA (MPMA), which permits an intuitive representation of disjunctive update and update with integrity constraints. An equivalent formulation of the MPMA in terms of Dijkstra’s semantics, based on the use of the weakest precondition and the strongest postcondition formula transformers, is then provided. The Dijkstra formulation is then used as a basis for a syntactic characterization of the MPMA, which is constructed by mapping an MPMA update of a knowledge base into a command in a simple Dijkstra style programming language. This characterization provides a decision procedure for computing entailments of the MPMA and serves as a basis for relating the belief update approach with temporal logic based and more procedurally based approaches for reasoning about action and change.
KeywordsKnowledge Base Temporal Logic Integrity Constraint Conjunctive Normal Form Formula Transformer
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