Séance du 12 avril

Jeudi 12 avril, 11h-13h

Salle Corbin

Abramsky's game semantic and dialogic

Pierre Cardascia

Abstract:

My first presentation in this GdT, "Vers une définition de stratégie sans hypothèse métalogique", began by questioning a metaphoric sentence from Girard: "Game semantics is a fighting sport; but a polite and civilised one: there is an arbiter who prevents nasty moves and bad behaviours. Ludics is more like wrestling: we knocked down the arbiter." I tried to interpret this "arbiter" as "metalogical hypotheses", I exposed some ideas about what should be a strategical behaviour in this context, inspired by different analyses of the Nim games (classic MeX-calculus, categorical analysis, question of the meaning of the cheat.

In my second intervention, "Formalism towards strategical behaviours", I showed the formal problems underlying the precedent talk: materialized players, variable number of players, both legal and illegal moves are possible... It gives us a "research plan". Then I finished by suggesting a "convergence" between the representation of dialogues and the representation of the trace in Abramsky's game semantics (with arenas etc).

For this session, "Abramsky's game semantics and dialogic", I will do more than suggesting, I will construct algorithms of translation between them, thanks to one little but new theorem of "arena-making dialogue":

For each set of particle rules , for each game, there exists a concrete justification [legitimation] such that this game forms a justified sequence of moves in an arena

It shall allow us to implement new results in dialogic (from categorial GS: Abramsky, Hyland, Ong ...) and fulfill the desiderata of the precedent talk. But we won't go too fast: to prove this theorem, I shall present and discuss the concepts of Abramsky's GS.

Séance du 5 avril

Jeudi 5 avril, 11h-13h
Salle D. Corbin

A Dynamic Logic of Interrogative Inquiry

Yacin Hamami

(Vrije Universiteit Brussel)

Abstract :

In this talk, I will propose a dynamic-epistemic analysis of the different epistemic operations constitutive of the process of interrogative inquiry, as described by Hintikka's Interrogative Model of Inquiry (IMI). I will develop a dynamic logic of questions for representing interrogative steps, based on Hintikka's treatment of questions in the IMI, along with a dynamic logic of inferences for representing deductive steps, based on the tableau method. I will then merge these two systems into a dynamic logic of interrogative inquiry which articulates a joint treatment of questions and inferences, providing thereby a unified framework representing the informational dynamics of interrogative inquiry.

I will provide sound and complete axiomatic systems for the three dynamic logics that I introduce, I will compare the framework with existing approaches and I will finally propose several directions for further works. This work is meant as a first step towards linking the IMI with the field of dynamic logics of information and rational agency.