On the Impact of Modal Depth in Epistemic Planning (Extended Version)

Epistemic planning is a variant of automated planning in the framework of dynamic epistemic logic. In recent works, the epistemic planning problem has been proved to be undecidable when preconditions of events can be epistemic formulas of arbitrary complexity , and in particular arbitrary modal depth. It is known however that when preconditions are propositional (and there are no postconditions), the problem is between Pspace and Expspace. In this work we bring two new pieces to the picture. First, we prove that the epistemic planning problem with propositional preconditions and without postconditions is in Pspace, and is thus Pspace-complete. Second, we prove that very simple epistemic preconditions are enough to make the epistemic planning problem undecidable: preconditions of modal depth at most two suffice

Reasoning about knowledge and messages in asynchronous multi-agent systems

International audienceWe propose a variant of public announcement logic for asynchronous systems. To capture asynchrony, we introduce two different modal operators for sending and receiving messages. The natural approach to defining the semantics leads to a circular definition, but we describe two restricted cases in which we solve this problem. The first case requires the Kripke model representing the initial epistemic situation to be a finite tree, and the second one only allows announcements from the existential fragment. After establishing some validities, we study the model checking problem and the satisfiability problem in cases where the semantics is well-defined, and we provide several complexity results.

Copy and remove as dynamic operators

In this article, we present a modal logic that extends the basic modal logic ML with two dynamic operators: copy (cp), which replicates the current model, labelling each copy with a different propositional symbol and respecting accessibility relations even between distinct copies; and remove (rm), which deletes paths in the model that satisfy certain intermediate conditions. We call the resulting logic ML(cp,rm). We study its computational complexity, and its relative expressivity with respect to (static) modal logics ML and ML(□−), and the dynamic epistemic Action Model Logic, AML.Fil: Areces, Carlos Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Van Ditmarsch, Hans. Open University; Países BajosFil: Fervari, Raul Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Maubert, Bastien. Università degli Studi di Napoli Federico II; ItaliaFil: Schwarzentruber, François. Universite de Rennes I; Francia. Centre National de la Recherche Scientifique; Francia. Institut de Recherche en Informatique et Systèmes Aléatoires; Franci

Games with Communication: from Belief to Preference Change

International audienceIn this work we consider simple extensive-form games with two players, Player A and Player B, where Player B can make announcements about his strategy. Player A has then to revise her preferences about her strategies, so as to better respond to the strategy she believes Player B will play. We propose a generic framework that combines methods and techniques from belief revision theory and social choice theory to address this problem. Additionally, we design a logic that Player A can use to reason and decide how to play in such games

Electronic Notes in Theoretical Computer Science

Abstract Dynamic Epistemic Logic (DEL) deals with the representation of situations in a multi-agent and dynamic setting. It can express in a uniform way statements about: (i) what is true about an initial situation (ii) what is true about an event occurring in this situation (iii) what is true about the resulting situation after the event has occurred. After proving that what we can infer about (ii) given (i) and (iii) and what we can infer about (i) given (ii) and (iii) are both reducible to what we can infer about (iii) given (i) and (ii), we provide a tableau method deciding whether such an inference is valid. We implement it in LOTRECscheme and show that this decision problem is NEXPTIME-complete. This contributes to the proof theory and the study of the computational complexity of DEL which have rather been neglected so far. Keywords: Dynamic epistemic logic, tableau method, computational complexity 1 This paper corrects the paper published under the same name and the same authors in the proceedings of M4M 2011. The rule ⊥ of the tableau method was missing. 2 We thank Sophie Pinchinat for helpful discussions and three reviewers for comments.

Electronic Notes in Theoretical Computer Science

Abstract Dynamic Epistemic Logic (DEL) deals with the representation of situations in a multi-agent and dynamic setting. It can express in a uniform way statements about: (i) what is true about an initial situation (ii) what is true about an event occurring in this situation (iii) what is true about the resulting situation after the event has occurred. After proving that what we can infer about (ii) given (i) and (iii) and what we can infer about (i) given (ii) and (iii) are both reducible to what we can infer about (iii) given (i) and (ii), we provide a tableau method deciding whether such an inference is valid. We implement it in LOTRECscheme and show that this decision problem is NEXPTIME-complete. This contributes to the proof theory and the study of the computational complexity of DEL which have rather been neglected so far. Keywords: Dynamic epistemic logic, tableau method, computational complexity 1 This paper corrects the paper published under the same name and with the same authors in the proceedings of M4M 2011. The rule ⊥ ′′ of the tableau method was missing. 2 We thank Sophie Pinchinat for helpful discussions and three reviewers for comments

Positions de petites planètes, obtenues à l'Observatoire d'Alger (équatorial photographique de 0m,33)

Sy Frédéric, Gonnessiat François, Maubert . Positions de petites planètes, obtenues à l'Observatoire d'Alger (équatorial photographique de 0m,33). In: Bulletin astronomique, tome 31, 1914. pp. 358-360

Reachability Games in Dynamic Epistemic Logic

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Asynchronous Announcements in a Public Channel

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