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Temporal Epistemic Gossip Problems

  • Martin C. CooperEmail author
  • Andreas Herzig
  • Frédéric Maris
  • Julien Vianey
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 11450)

Abstract

Gossip problems are planning problems where several agents have to share information (‘secrets’) by means of phone calls between two agents. In epistemic gossip problems the goal can be to achieve higher-order knowledge, i.e., knowledge about other agents’ knowledge; to that end, in a call agents communicate not only secrets, but also agents’ knowledge of secrets, agents’ knowledge about other agents’ knowledge about secrets, etc. Temporal epistemic gossip problems moreover impose constraints on the times of calls. These constraints are of two kinds: either they stipulate that a call between two agents must necessarily be made at some time point, or they stipulate that a call can be made within some possible (set of) interval(s). In the non-temporal version, calls between two agents are either always possible or always impossible. We investigate the complexity of the plan existence problem in this general setting. Concerning the upper bound, we prove that it is in NP in the general case, and that it is in P when the problem is non-temporal and the goal is a positive epistemic formula. As for the lower bound, we prove NP-completeness for two fragments: problems with possibly negative goals even in the non-temporal case, and problems with temporal constraints even if the goal is a set of positive atoms.

Keywords

Epistemic planning Temporal planning Gossip problem Complexity Epistemic logic 

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Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Martin C. Cooper
    • 1
    Email author
  • Andreas Herzig
    • 1
  • Frédéric Maris
    • 1
  • Julien Vianey
    • 1
  1. 1.IRIT, CNRS, Univ. ToulouseToulouse Cedex 9France

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