Logics of time and computation
Logics of time and computation
The logic of nonmonotonicity (research note)
Artificial Intelligence
Propositional knowledge base revision and minimal change
Artificial Intelligence
Logic and information flow
First steps in modal logic
Counterfactuals and Updates as Inverse Modalities
Proceedings of the Sixth Conference on Theoretical Aspects of Rationality and Knowledge
Tableaux for Reasoning About Atomic Updates
LPAR '01 Proceedings of the Artificial Intelligence on Logic for Programming
Belief Revision and the Ramsey Test: A Solution
AI*IA 01 Proceedings of the 7th Congress of the Italian Association for Artificial Intelligence on Advances in Artificial Intelligence
Weak AGM postulates and strong Ramsey Test: a logical formalization
Artificial Intelligence
Conditional Doxastic Models: A Qualitative Approach to Dynamic Belief Revision
Electronic Notes in Theoretical Computer Science (ENTCS)
Davidson and Reiter on Actions
Fundamenta Informaticae - Logic for Pragmatics
EPDL: a logic for causal reasoning
IJCAI'01 Proceedings of the 17th international joint conference on Artificial intelligence - Volume 1
Weak AGM postulates and strong Ramsey Test: A logical formalization
Artificial Intelligence
Davidson and Reiter on Actions
Fundamenta Informaticae - Logic for Pragmatics
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We point out a simple but hitherto ignored link between the theoryof updates, the theory of counterfactuals, and classical modal logic: update is a classicalexistential modality, counterfactual is a classical universalmodality, and the accessibility relations corresponding to these modalities are inverses. The Ramsey Rule (often thought esoteric) is simply an axiomatisation of this inverse relationship. We use this fact to translate between rules for updates andrules for counterfactuals. Thus, Katsuno and Mendelzon‘s postulatesU1--U8 are translated into counterfactual rules C1--C8(Table VII), and many of the familiar counterfactual rulesare translated into rules for updates (Table VIII). Ourconclusions are summarised in Table V. From known properties of inverse modalities we deduce that notall rules for updates may be translatedinto rules for counterfactuals, and vice versa. We present asyntactic condition which is sufficient to guarantee that atranslation from update to counterfactual (or vice versa) is possible.