Independent agents in branching time : towards a unified framework for reasoning about multiagent systems

par Nicolas Troquard

Thèse de doctorat en Informatique et télécommunications

Sous la direction de Andreas Herzig et de Laure Vieu.

Soutenue en 2007

à Toulouse 3 en cotutelle avec Trente, Italie .

mots clés

• Philosophy of action
• Action
• Agency
• Coalition logic
• Stit
• Coalition
• Modal logic
• Ontology
• Philosophie de l'action
• Modalité (logique)
• Intelligence artificielle répartie

Titre traduit

Agents indépendants dans le temps ramifié : vers un cadre unifié de raisonnement sur les systèmes multi-agents

Résumé

Le travail présenté dans cette thèse est une étude multidisciplinaire de le notion de réalisation (`agency'). Nous construisons de nouvelles approches formelles à partir de la littérature de la réalisation en philosophie de l'action, théorie des jeux ou informatique. Nous cherchons particulièrement à confronter les différentes logiques issues de traditions diverses, et à transférer entre elles leurs résultats et méthodes respectifs. La théorie du STIT de Belnap et Perloff est notre cadre d'expérimentation.

Résumé

The work presented in this thesis is a multidisciplinary study of the notion of agency. We build new formal approaches starting on the literature of agency in philosophy of action, game theory or computer science. Belnap and Perloff's STIT theory is our frame of experimentation. This is a logic that stems from philosophy of action based on the observation that an action can be identi_ed with what it brings about. In this tradition, the sentence. Ishmael sails on board the Pequod. Will be paraphrased by. Ishmael sees to it that Ishmael sails on board the Pequod. . Our first contribution is to simplify the axiomatics of a version of the logic restrained to individual agency and without temporal aspects. This allows us to simplify the semantics of STIT as well as to discover a link with product logics. We establish the NEXPTIME-completeness of the problem of satisfiability. We capitalize on the simplifications and extend the axiomatization to coalitional actions. We show that we can embed Coalition Logic in the resulting logic. We also provide an epistemic extension and use it to tackle the problem of epistemically uniform strategies. Then we study further the temporal aspects of agency. We first do it by way of a logic combining STIT with a dynamic logic providing actions with duration, that can be deliberatively continued or aborted along time. We then give an embedding of Alternating-time Temporal Logic in a slightly adapted strategic STIT logic. Having developed a neat understanding of relevant structures of agency, we propose a fine-grained ontology of action and agency.