J. J. Lang

Boolean games are a logical setting for representing strategic games in a succinct way, taking advantage of the expressive power and conciseness of propositional logic. A Boolean game consists of a set of players, each of which controls a set of propositional variables and has a specific goal expressed by a propositional formula. We show here that Boolean games are a very simple setting, yet sophisticated enough, for analysing the formation of coalitions. Due to the fact that players have dichotomous preferences, the following notion emerges naturally: a coalition in a Boolean game is efficient if it has the power to guarantee that all goals of the members of the coalition are satisfied. We study the properties of efficient coalitions

In this paper, the problem of purifying an assumption-based theory KB, i.e., identifying the right extension of KB using knowledge-gathering actions (tests), is addressed. Assumptions are just normal defaults without prerequisite. Each assumption represents all the information conveyed by an agent, and every agent is associated with a (possibly empty) set of tests. Through the execution of tests, the epistemic status of assumptions can change from "plausible" to "certainly true", "certainly false" or "irrelevant", and the KB must be revised so as to incorporate such a change. Because removing all the extensions of an assumption-based theory except one enables both identifying a larger set of plausible pieces of information and renders inference computationally easier, we are specifically interested in finding out sets of tests allowing to purify a KB (whatever their outcomes). We address this problem especially from the point of view of computational complexity.

We analyze the expressivity, succinctness, and complexity of a family of languages based on weighted propositional formulas for the representation of utility functions. The central idea underlying this form of preference modeling is to associate numerical weights with goals specified in terms of propositional formulas, and to compute the utility value of an alternative as the sum of the weights of the goals it satisfies. We define a large number of representation languages based on this idea, each characterized by a set of restrictions on the syntax of formulas and the range of weights. Our aims are threefold. First, for each language we try to identify the class of utility functions it can express. Second, when different languages can express the same class of utility functions, one may allow for a more succinct representation than another. Therefore, we analyze the relative succinctness of languages. Third, for each language we study the computational complexity of the problem of finding the most preferred alternative given a utility function expressed in that language

This special issue presents a selection of papers in Knowledge Representation in Artificial Intelligence , intended to illustrate the depth and breadth of current research in the area. It comes just over 25 years since a similar special issue of the Journal of Philosophical Logic appeared on the topic Philosophical Logic and Artificial Intelligence [15]. This latter special issue covered work addressing the use of logic, in one form or another, for representing and reasoning with knowledge. The papers of the 1988 special issue give a good indication of major themes of research at the time: reasoning about belief and knowledge [5], tractable logical reasoning [10], nonmonotonicity [11], and reasoning about action [13]. These topics can be considered to be centrally in KR; the current issue then also serves to indicate how the field has broadened and evolved over the last 25 years.Traditionally the area of Knowledge Representation has been seen as “the field of study concerned w ..

Several tasks in artificial intelligence require the ability to find models about knowledge dynamics. They include belief revision, fusion and belief merging, and abduction. In this paper, we exploit the algebraic framework of mathematical morphology in the context of propositional logic and define operations such as dilation or erosion of a set of formulas. We derive concrete operators, based on a semantic approach, that have an intuitive interpretation and that are formally well behaved, to perform revision, fusion and abduction. Computation and tractability are addressed, and simple examples illustrate the main results.

L’intervention que reprend cet article porte sur un cadre-dispositif singulier de thérapie familiale basé sur l’épistémologie psychanalytique groupale. Ce cadre est singulier dans la mesure où il a été tenté d’articuler un travail entre groupe de thérapeutes et néo-groupe. La réflexion développée ici s’origine dans la clinique des auteurs : lorsqu’ils parlent en groupe d’une famille, la règle d’association libre les amène fréquemment à évoquer une autre famille rencontrée précédemment en séance. Quelle est la nature et la fonction de cette résonance? L’article pose l’hypothèse d’un nouveau contre-transfert : le contre-transfert transfamilial. Une vignette clinique permet d’illustrer le cheminement qui a conduit les auteurs à y aboutir.

This article begins with a review of studies in perception and depth psychology concerning the experience of exposure to sacred artworks in Roman Catholic and Eastern Orthodox contexts. This follows with the results of a qualitative inquiry involving 45 Roman Catholic, Eastern and Coptic Orthodox, and Protestant Christians in Canada. First, participants composed narratives detailing memories of spiritual experiences involving iconography. Then, in the context of a darkened room evocative of a sacred space, they viewed artworks depicting Biblical themes and interpreted their meanings. Stimuli included “Western” paintings from the Roman tradition—a selection from the Gothic, Northern Renaissance, and Renaissance canon—and matched “Eastern” icons in the Byzantine style. Spiritual experience narratives were analyzed in terms of word frequencies, and interpretations of sacred artworks were analyzed thematically. Catholics tended to utilize emotional language when recalling their spiritual experiences, while religious activity was most often the concern of Protestants, and Orthodox Christians wrote most about spiritual figures and their signifiers. A taxonomy of response styles was developed to account for participants’ interpretations of Western and Eastern artworks, with content ranging from detached descriptions to projective engagement with the art-objects. Our approach allows for representation of diverse Christians’ interpretations of sacred art, taking into consideration personal, collective, and cultural-religious sources of meaning. Our paradigm also offers to enrich our understanding of the numinous or emotional dimension of mystical contact.

Based on “laws” of contagion and similarity, it is understood that people tend to believe that meanings associated with one object may be transferred onto another, and the meanings of the first may “contaminate” the second. The perceived contamination may influence the individual’s way of interacting with the object. We aimed to produce a rich description of individual differences that predict intuitive judgments in response to scenarios involving activation of contagion heuristics. Adolescents and adults in Germany completed a survey and provided rated responses to hypothetical scenarios. They also gave open-ended remarks on one scenario: whether they would wear a sweater that had belonged to Adolf Hitler if they were cold. Content analysis produced a composite description of reflections with insights into historical consciousness in contemporary Germany. Also examined was the extent to which quantitative responses were related to demographics, personality characteristics, supernatural beliefs, and responses to other scenarios.

The study of genocide and mass atrocity abounds with references to emotions: fear, anger, horror, shame and hatred. Yet we don't understand enough about how 'ordinary' emotions behave in such extreme contexts. Emotions are not merely subjective and interpersonal phenomena; they are also powerful social and political forces, deeply involved in the history of mass violence. Drawing on recent insights from philosophy, psychology, history, and the social sciences, this volume examines the emotions of perpetrators, victims, and bystanders. Editors Thomas Brudholm and Johannes Lang have brought together an interdisciplinary group of prominent scholars to provide an in-depth analysis of the nature, value, and role of emotions as they relate to the causes and dynamics of mass atrocities. The result is a new perspective on the social, political, and moral dimensions of emotions in the history of collective violence and its aftermath.