Conditional Inference under Disjunctive Rationality


  • Richard Booth Cardiff University, United Kingdom
  • Ivan Varzinczak CRIL, Univ. d’Artois & CNRS, France CAIR, Computer Science Division, Stellenbosch University, South Africa ISTI-CNR, Italy


Nonmonotonic Reasoning


The question of conditional inference, i.e., of which conditional sentences of the form ``if A then, normally, B'' should follow from a set KB of such sentences, has been one of the classic questions of AI, with several well-known solutions proposed. Perhaps the most notable is the rational closure construction of Lehmann and Magidor, under which the set of inferred conditionals forms a rational consequence relation, i.e., satisfies all the rules of preferential reasoning, *plus* Rational Monotonicity. However, this last named rule is not universally accepted, and other researchers have advocated working within the larger class of *disjunctive* consequence relations, which satisfy the weaker requirement of Disjunctive Rationality. While there are convincing arguments that the rational closure forms the ``simplest'' rational consequence relation extending a given set of conditionals, the question of what is the simplest *disjunctive* consequence relation has not been explored. In this paper, we propose a solution to this question and explore some of its properties.




How to Cite

Booth, R., & Varzinczak, I. (2021). Conditional Inference under Disjunctive Rationality. Proceedings of the AAAI Conference on Artificial Intelligence, 35(7), 6227-6234. Retrieved from



AAAI Technical Track on Knowledge Representation and Reasoning