We show how in the propositional case both Reiter's and Scherl & Levesque's solutions to the frame problem can be modelled in dynamic epistemic logic (DEL), and provide an optimal regression algorithm for the latter. Our method is as follows: we extend Reiter's framework by integrating observation actions and modal operators of knowledge, and encode the resulting formalism in DEL with announcement and assignment operators. By extending Lutz' recent satisfiability-preserving reduction to our logic, we establish optimal decision procedures for both Reiter's and Scherl & Levesque's approaches: satisfiability is NP-complete for one agent, PSPACE-complete for multiple agents and EXPTIME-complete when common knowledge is involved.
@InProceedings{vanditmarsch_et_al:DagSemProc.07351.15, author = {van Ditmarsch, Hans and Herzig, Andreas and de Lima, Tiago}, title = {{Optimal Regression for Reasoning about Knowledge and Actions}}, booktitle = {Formal Models of Belief Change in Rational Agents}, pages = {1--22}, series = {Dagstuhl Seminar Proceedings (DagSemProc)}, ISSN = {1862-4405}, year = {2007}, volume = {7351}, editor = {Giacomo Bonanno and James Delgrande and J\'{e}r\^{o}me Lang and Hans Rott}, publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik}, address = {Dagstuhl, Germany}, URL = {https://drops.dagstuhl.de/entities/document/10.4230/DagSemProc.07351.15}, URN = {urn:nbn:de:0030-drops-12077}, doi = {10.4230/DagSemProc.07351.15}, annote = {Keywords: Reasoning about action and change, reasoning about knowledge, situation calculus, frame problem, dynamic epistemic logic} }
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