KR2020Proceedings of the 17th International Conference on Principles of Knowledge Representation and ReasoningProceedings of the 17th International Conference on Principles of Knowledge Representation and Reasoning

Rhodes, Greece. September 12-18, 2020.

Edited by

ISSN: 2334-1033
ISBN: 978-0-9992411-7-2

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Copyright © 2020 International Joint Conferences on Artificial Intelligence Organization

Changing Beliefs about Domain Dynamics in the Situation Calculus

  1. Toryn Q. Klassen(University of Toronto, Vector Institute)
  2. Sheila A. McIlraith(University of Toronto, Vector Institute)
  3. Hector J. Levesque(University of Toronto)


  1. Reasoning about knowledge, beliefs, and other mental attitudes-General
  2. Reasoning about actions and change, action languages-General
  3. Belief revision and update, belief merging, information fusion-General
  4. Nonmonotonic logics, default logics, conditional logics-General


Agents change their beliefs about the plausibility of various aspects of domain dynamics -- effects of physical actions, results of sensing, and action preconditions -- as a consequence of their interactions with the world. In this paper we propose a way to conveniently represent domain dynamics in the situation calculus to support such belief change. Furthermore, we suggest patterns to follow when writing the axioms that describe the effects of actions, and prove how these patterns can control the extent to which observations change the agent's beliefs about action effects. We also discuss the relation of our work to the AGM postulates for belief revision. Finally, we show how beliefs about domain dynamics can be incorporated into a form of regression rewriting to support reasoning.