Reprise 2013-2014. Séance du 14 novembre 2013

Le Groupe de Travail reprend ses activités. Pour le premier semestre de l'année 2013-2014, les séances auront lieu le jeudi. Un prochain billet donnera toutes les informations.

Le GdT reprend dès le 14 novembre (la semaine prochaine) avec

Structures and Properties

Matthieu Gallais

Résumé :
In order to define the notion of compatibility between fictional models and target systems, not only the properties, but also the second-order relations between those properties need to be preserved.
According to the structuralist view of models, a target system is compatible with a model if there is an isomorphism mapping between their structures.
But an isomorphism is just a structural identity that ensures that all the properties in a structure have a counterpart in the other structure, not that it is the same property.
Then, in which sense is a property of a model-object linked to a property of real object?

Séance du 20 juin (attention au lieu!)

Modelling of a cognitive agent: processes and logic.

Christel Grimaud

20 juin, 13h-15h
Salle F0.13, Maison de la Recherche (attention, salle différente)

Résumé :
This talk will be two-fold. First I will introduce the problem of providing a logical and neural model for a cognitive agent, and ask what can be reasonable goals, and what requisites this entails on the logic to use. More precisely, I will distinguish between two kinds of reasoning processes, one I call deliberative reasoning, and the other automatic inferences. I will explain why it is reasonable to hope to provide a neural model for automatic inferences, whereas it is not for deliberative reasoning. Thus restricting myself to automatic inferences, I will suggest a plausible neural process for these, and ask what logic could model it. This will bring me to dismiss frst any logical modelling relying on possible worlds, and second, any logical modelling involving defeating
relations.
The second half of the talk will essentially take up again the content of my recently submitted paper. I will present what I think is a suitable logic for automatic inferences, namely the one based on partial worlds models (which I introduced already in my previous talk). Then I will tackle again the problem of providing a complete set of rules for inference relations induced by these models. In my previous talk, I proposed to do this by the means of a compatibility relation. This time I will analyse the question in terms of defnable sets of partial worlds, and propose instead to enrich the language with an additional connective. Within this renewed framework, I will provide two representation theorems: one for inference relations induced by admissible smooth models, and another for relations induced by admissible ranked models.

Séance du 30 mai

Repetition ranks: "why don't you just keep Felscher's rules?"

Nicolas Clerbout

30 mai, 11h-13h (Attention à l'horaire)
Salle D. Corbin

Résumé :
Apart from S. Rahman and his collaborators, most of the people knowing and/or working on dialogues keep Felscher's account in mind. This is mostly because his presentation is technically precise and because he provided one of the first accurate and complete proofs of an equivalence theorem in [3]. Even in the last decade, almost every work about dialogues which was not done by a direct collaborator of S. Rahman was done with Felscher's rules: for example [4, 5, 6, 7]. Thus, it is no suprise that we often face the question  "Why don't you just keep Felscher's rules?", especially in reaction to the device of repetition ranks as I introduced it [1, 2].


The main purpose of this talk is to give an answer to this disguised reproach. To do this I will recall and comment quite extensively Felscher's rules. Although it is an excuse to insist once more on the benefits of repetition ranks, there is another good reason for this flashback. As dialogicians we must be able to discuss with people knowing only Felscher's rules, if only to explain and convince that our account should be preferred. So we must know the answers to questions such as:
- What is the E-rule and what is the big deal with it?
- Does Felscher have something like ranks?
- etc
The comparison is also helpful to get a good grip on important issues related but not limited to proving results: finite vs. infinite plays, separation of rules and strategies, redundancy of rules, etc.

[1] Clerbout, N.: 2013a, ``First-Order Dialogical Games and Tableaux''. To appear in Journal of Philosophical Logic.
[2] Clerbout, N.: 2013b, Etude sur quelques sémantiques dialogiques. Concepts fondamentaux et éléments de metathéorie. PhD dissertation, Lille/Leiden.
[3] Felscher, W.: 1985, ``Dialogues, Strategies, and Intuitionistic Provability''. Annals of Pure and Applied Logic 28, pp. 217-254.
[4] Sorensen, M. and Urzyczyn, P.: 2006, Lectures on the Curry-Howard Isomorphism, Elsevier.
[5] Sorensen, M. and Urzyczyn, P.: 2007, ``Sequent Calculus, Dialogues, and Cut Elimination''. In Barendsen et al. (eds.), Reflections on Type Theory, Lambda Calculus, and the Mind, pp. 253-261.
[6] Uckelman, S.: ``Some remarks on the E-rule in dialogical logic''. Submitted manuscript, available on the author's website.
[7] Uckelman, S., Alama, J. and Knocks, A.: ``A curious dialogical logic and its composition problem''. Submitted manuscript.

Séance de rattrapage le 23 mai

La séance initialement prévue le 16 mai aura lieu le jeudi 23 mai.

Attention, l'horaire n'est pas l'horaire habituel : la séance se tiendra de 11h à 13h - mais le lieu reste le même que d'habitude (Salle Corbin, STL).

Dialogical dialogues are 2*2 matrices of formulas

Pierre Cardascia

Résumé :
The separation of particle rules and structural rules in dialogic causes a strange case of double justification when we try to transfer the dialogical logic in GS.
In my former talk, I spoke about the difference between the local formulation of rules in GS versus the global formulation of dialogical logic, which is the origine of this double justification: in dialogic, one needs (sometimes) to know the entire history of the dialogue to know what moves he can do, and it doesn't fit very well with the compositionality of arenas in GS. To solve that, I made modifications in the formalism (but not so large in the contents), introduced a notion of position, and used it to give another definition of moves (better I hope).

Séance du 16 mai ANNULEE

SEANCE ANNULEE POUR CAUSE DE GREVE DES TRANSPORTS

La séance de remplacement sera annoncée dès que possible

On Abramsky's game semantics 

(continued)

Pierre Cardascia

16 mai 2013, 13h-15h
Salle D. Corbin

Séance du 4 avril

Nature logique ou sémantique de la contradiction chez Aristote : 

le questionnement suscité par les Réfutations Sophistiques

Myriam Hecquet

4 avril 2013, 13h-15h
Salle D. Corbin


Résumé : Dans les Réfutations Sophistiques, l'analyse des paralogismes met en jeu les notions de réfutation (pour toutes les réfutations apparentes), de déduction (pour celles qui ne "tiennent pas à l'expression") et de contradiction (pour celles qui "tiennent à l'expression"), semblant ainsi mettre la contradiction du coté de l'analyse sémantique et réserver l'analyse formelle à la déduction. Pourtant la frontière est perméable et nécessite d'examiner la question de plus près. Cela me permet de revenir sur le rôle de "démonstration par réfutation" du principe de non-contradiction dans Métaphysique Gamma.

Séance du jeudi 21 mars

Dialogue avec des êtres d'un autre type

Matthieu Fontaine

21 mars 2013, 13h-15h
Salle D. Corbin (UMR STL)


Résumé : Dans la théorie artefactuelle, la définition du statut ontologique des entités fictionnelles intègre la notion de dépendance ontologique. S'appuyant sur la sémantique de Fontaine & Rahman [2013] et les premiers développements de Fontaine [2010], l'objectif consiste à définir des relations de dépendances ontologiques dans le contexte de la logique dialogique libre. Pour ce faire, on introduit ces relations dans le langage au moyen de prédicats intentionnels spécifiques, dont la sémantique est donnée par des règles de particules. Certains aspects de telles relations peuvent en fait être capturés en termes de combinaisons de choix opérés lors de l'attaque ou la défense de quantificateurs. Il semblerait sur ce point que les règles de particules qu'on définit pourraient s'apparenter à des règles de formations de prédicats de la théorie des types.

Références

Fontaine, M. 2010. Weak Impermeabilism for Fictionality in a Dialogical Framework, Symposium ``New directions in Dialogical Logics''. 14th CLMPS, Nancy

Fontaine, M. & Rahman, Sh. 2013. ``Towards a Semantics for the Artifactual Theory of Fiction and Beyond (forthcoming)