Reasoning in the Situation Calculus with Limited Belief Extended Abstract The Epistemic Situation Calculus 0 1 2 3 Christoph Schwering School of Computer Science and Engineering The University of New South Wales Sydney NSW 2052 , Australia [McCarthy, 1963] John McCarthy. Situations, actions, and causal laws. Technical report, Stanford University , 1963 [Reiter, 2001] Ray Reiter. Knowledge in Action: Logical Foundations for Specifying and Implementing Dynamical Systems. The MIT Press , 2001 [Schwering, 2017] Christoph Schwering. A reasoning system for a first-order logic of limited belief. In Proceedings of the Twenty-Sixth International Joint Conference on Artificial Intelligence , 2017

Action formalisms like the situation calculus [McCarthy, 1963; Reiter, 2001] are powerful tools for modelling dynamic domains. However, these formalisms, typically based on firstorder logic, are also notorious for having little practical relevance due to their computational complexity. This paper introduces an expressive yet computationally feasible variant of the situation calculus. To this end, we amalgamate the situation calculus with a first-order logic of limited belief [Schwering, 2017]. Queries are evaluated at a specific belief level, which intuitively limits the maximum allowed reasoning effort. Reasoning in this logic is sound and decidable. An implementation has been made available.

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[Lakemeyer and Levesque, 2011] Gerhard Lakemeyer and Hector J. Levesque. A semantic characterization of a useful fragment of the situation calculus with knowledge. Artificial Intelligence, 175(1), 2011.