OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible 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 gen-eral 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 NPcompleteness for two fragments: problems with possibly neg-ative goals even in the non-temporal case, and problems with temporal constraints even if the goal is a set of positive atoms.
In REF such problem were studied further in the presence of temporal constraints, i.e., a given call can only (or has to) be made within a given time interval.
Temporal Epistemic Gossip Problems
EUMAS
Computer Science