, Volume 40, Issue 4, pp 445-472
Date: 19 Apr 2011

Reasoning About Permitted Announcements

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We formalize what it means to have permission to say something. We adapt the dynamic logic of permission by van der Meyden (J Log Comput 6(3):465–479, 1996) to the case where atomic actions are public truthful announcements. We also add a notion of obligation. Our logic is an extension of the logic of public announcements introduced by Plaza (1989) with dynamic modal operators for permission and for obligation. We axiomatize the logic and show that it is decidable.

A prior version of this work was presented at the ESSLLI 2009 workshop Logical Methods for Social Concepts, Bordeaux, France, 2009 [3]. In that paper a different semantics for the permission operator was presented, and it did not have an obligation operator. Hans van Ditmarsch is listed as an author of this prior version, and has also actively contributed to the final version. However, he has withdrawn as an author of the final version, because he is an editor of the Journal of Philosophical Logic. Pablo Seban was his PhD student at the time of submission. Hans has not been involved in the decision process for this special issue contribution at any time or in any way, and he is ignorant of the reviewers of the contribution.