The undecidability of group announcements

T. Ågotnes, H.P. Van Ditmarsch, Tim French

    Research output: Chapter in Book/Conference paperConference paperpeer-review

    5 Citations (Scopus)


    Copyright © 2014, International Foundation for Autonomous Agents and Multiagent Systems ( All rights reserved. This paper addresses and solves the long-standing open problem of whether Group Announcement Logic (GAL) is de-cidable. GAL is a dynamic epistemic logic for reasoning about which states of knowledge a group of agents can make come about by sharing their knowledge, with an operator for quantifying over all truthful public announcements that can be made by the group. We show that the satisfiability problem for the logic is undecidable; it is co-RE complete.
    Original languageEnglish
    Title of host publicationProceedings of the 13th International Conference on Autonomous Agents and Multiagent Systems (AAMAS 2014)
    PublisherInternational Foundation for Autonomous Agents and Multiagent Systems
    ISBN (Print)9781634391313
    Publication statusPublished - 2014
    EventThe undecidability of group announcements - Paris, France.
    Duration: 1 Jan 2014 → …


    ConferenceThe undecidability of group announcements
    Period1/01/14 → …


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