2020 Volume 32 Issue 4 Pages 768-777
In Epistemic Situation Calculus (ES) proposed by Lakemeyer and Levesque, by assuming a situation as a possible world, it is possible to interpret an action as a kind of modality. Moreover, since the state of knowledge of the agent is interpreted by the equivalence relation to the world after the action, knowledge representation based on granulation is possible. In this paper, we apply granular reasoning to the epistemic situation calculus by interpreting actions as modalities and granules of possible worlds as states. The zoom reasoning proposed by Murai et al. is regarded as a cognitive action and is incorporated into the ES as an abstraction and refinement action by the granularity of the situation. The relationship between rough sets and semantic interpretation based on Belnap’s four-valued logic is given as a model of ES, and a model of ES with possible worlds and four-valued logic is presented.
