BackgroundNowadays, social media have become central in the daily lives of people, including healthcare professionals. Fears arise that the accelerated growth of these social platforms was not accompanied by the appropriate training of the healthcare students and workers on the professional use of social media. This study primarily aimed to assess the awareness of the healthcare students at Beirut Arab University, Lebanon on the professional standards of social media. It also aimed to assess the presence of differences in the practices (...) and attitudes of healthcare students according to gender and major.MethodsA cross-sectional study was designed, and a paper-based questionnaire was distributed to healthcare students. Chi-Square test was used to analyse certain findings.ResultsOut of 1800 students approached, 496 participated in the questionnaire. All participants used social media. Only 19.5% (96/496) of them had received a structured education on the professional use of social media during their university study. The majority of students (349/488, 71.5%) thought that the professional standards on social media are distinct from those established in face-to-face interactions. Female students were more likely to get adequate answers in accordance with international guidelines. There were statistically significant differences in the practices and attitudes of students belonging to different majors (p value < 0.05).ConclusionThe line between what is professional on social media, and what is not, remains blurred for healthcare students. This study uncovered the need for clear and updated evidence-based guidelines assisting students in making the most appropriate decisions in the various online scenarios faced in healthcare practice. (shrink)

We show in this paper that the AGM postulates are too weak to ensure the rational preservation of conditional beliefs during belief revision, thus permitting improper responses to sequences of observations. We remedy this weakness by proposing four additional postulates, which are sound relative to a qualitative version of probabilistic conditioning. Contrary to the AGM framework, the proposed postulates characterize belief revision as a process which may depend on elements of an epistemic state that are not necessarily captured by a (...) belief set. We also show that a simple modification to the AGM framework can allow belief revision to be a function of epistemic states. We establish a model-based representation theorem which characterizes the proposed postulates and constrains, in turn, the way in which entrenchment orderings may be transformed under iterated belief revision. (shrink)

The paper outlines the interpretation of Sufism formulated by Mohamed Abed Al-Jabri, a contemporary Moroccan philosopher and critic of the Arabic tradition. According to him, Sufism, unknown to Arabic culture until the advent of Islam, originated through a historical conspiracy whereby the Persians attempted to weaken their new Arabic colonisers. Sufism is viewed by him as an evasion and a detachment from life and its problems. It leads its adepts, through the mystical journey, to renounce material life. It plunges its (...) adepts into a way of life where the annihilation of the self in God represents the central value. This annihilation of the self in deity is possible only through the blind obedience of the Seeker to his Master. Therefore, Sufism can only thrive by using tyrannical means. It demands that its adepts, through following a predestined path chosen by God, lose their own volition and freedom in favour of their Master. Breaking the law at the end of the Seeker’s mystical journey reflects, paradoxically, a spiritual accomplishment. Additionally, Sufi orders maintain a congenial relationship with political tyranny. Consequently, I argue, Sufism leads to a loss of human responsibility for oneself and other beings. I also claim that in a post-tyrannical Arabic society, where responsibility for oneself and one’s community should be the centralvalue, Sufi ethics are unable to play a role in the promotion of modern values. For this reason, it should be prevented from shaping the political and social choices of a modern society and constrained to the mystical realm. (shrink)

Recent work has shown that the input-output behavior of some common machine learning classifiers can be captured in symbolic form, allowing one to reason about the behavior of these classifiers using symbolic techniques. This includes explaining decisions, measuring robustness, and proving formal properties of machine learning classifiers by reasoning about the corresponding symbolic classifiers. In this work, we present a theory for unveiling the _reasons_ behind the decisions made by Boolean classifiers and study some of its theoretical and practical implications. (...) At the core of our theory is the notion of a _complete reason,_ which can be viewed as a necessary and sufficient condition for why a decision was made. We show how the complete reason can be used for computing notions such as sufficient reasons (also known as PI-explanations and abductive explanations), how it can be used for determining decision and classifier bias and how it can be used for evaluating counterfactual statements such as “a decision will stick even if...because....” We present a linear-time algorithm for computing the complete reasoning behind a decision, assuming the classifier is represented by a Boolean circuit of appropriate form. We then show how the computed complete reason can be used to answer many queries about a decision in linear or polynomial time. We finally conclude with a case study that illustrates the various notions and techniques we introduced. (shrink)

La pensée de Heidegger sur le dieu cherche à trouver, retrouver ou découvrir pour celui-ci et dans son histoire une dimension originaire et inaugurale et en même temps non-métaphysique, une voix qui parle dans un autre langage à venir et qui soit celle du monde et des mortels. Cette considération du dieu se rencontre aussi dans les tentaives mystiques d'Orient, en particulier dans le soufisme de la voie (tarika, طريقة) d'Ibn 'Arabi, qui retrouve son dieu autrement que dans sa dimension (...) de créateur. Ce dieu se révèle comme intrinsèque au monde - il n'est jamais sans monde, et surtout il s'avère avoir l'homme pour gardien, pour berger de sa parole et de ce même monde. Le points de convergence des deux pensées sont multiples. Nous offrons ici l'ébauche d'un dialogue qui s'avérera certainement très fructueux pour la pensée du dieu, surtout compte tenu des recherches actuelles concernant le sens du spirituel et du religieux. Le recueillement, l'intériorité qui dépasse la volonté et le défi qu'ils posent à la subjectivité sont au cœur des articlations que nous établissons das ce texte. (shrink)

We address in this paper the problem of counting the models of a propositional theory under incremental changes to its literals. Specifcally, we show that if a propositional theory Δ is in a special form that we call smooth, deterministic, decomposable negation normal form, then for any consistent set of literals S, we can simultaneously count the models of Δ ∪ S and the models of every theory Δ ∪ T where T results from adding, removing or flipping a literal (...) in S. We present two results relating to the time and space complexity of compiling propositional theories into sd-DNNF. First, we show that if a conjunctive normal form has a bounded treewidth, then it can be compiled into an sd-DNNF in time and space which are linear in its size. Second, we show that sd-DNNF is a strictly more space efficient representation than Free Binary Decision Diagrams. Finally, we discuss some applications of the counting results to truth maintenance systems, belief revision, and model-based diagnosis. (shrink)

Ce livre propose d'aller au plus intime de la pensée heideggerienne dans sa maturité, qui récapitule ses moments clefs au sein de la constellation des quatre : les dieux, les mortels, la terre et le ciel ; pour découvrir, comme vérité de la relation entre eux, la dimension divine, disposée, dispensée, plurivoque et déterminante dans l'avènement à partir de l'événement appropriant, l'Ereignis. Arriver à cet envoi destinal du divin comme essentiel à la pensée de Heidegger, n'a pu se faire, qu'en (...) prenant d'abord le chemin du dieu heideggerien, pour en dégager le sens et le dépasser vers son fondement puis ce qui a rendu ce dernier possible : ce sur quoi il repose, même dans un oubli, dont les textes ne donnent le sens que sous des moments précis, aboutissant, dans leur être-ensemble et les-uns-pour-les-autres, à l'installation d'un monde par l'Ereignis sous le signe du divin. Il a fallu donc dégager ce qu'est le dieu de ses sens accumulés - en passant par le Dieu créateur, au dieu qui sauvegarde puis au dieu Inconnu - pour retrouver ce qui le donne comme tel, et ensuite chercher la trace de ce don. Ce travail nous a permis de déceler, au fur des textes - non sans surprise et même quelque joie - les traces et les opérations du divin auprès de chacun des éléments de ce qui est devenu le Quadriparti. Une fois ce dégagement effectué avec le plus de précision possible, nous avons pu en identifier les modalités au sein du Geviert, sa manière de " s'installer ", toujours différente, et ses conséquences sur le monde et le destinal. Cela nous a permis enfin d'entreprendre un changement éclairant dans le sens de plusieurs topoi heideggeriens, à savoir l'histoire, l'art, la parole et le poème - éclairage qui donne à chacun son sens fondamental depuis l'expression divine. Ce travail se veut aussi, dans ses dernières pages, un questionnement renouvelé sur les problèmes fondamentaux du divin chez Heidegger, et demande donc de reprendre les textes dans une la perspective qu'il ouverte pour en développer toute la portée. (shrink)

We address in this paper the problem of counting the models of a propositional theory under incremental changes to its literals. Specifcally, we show that if a propositional theory Δ is in a special form that we call smooth, deterministic, decomposable negation normal form (sd-DNNF), then for any consistent set of literals S, we can simultaneously count (in time linear in the size of Δ) the models of Δ ∪ S and the models of every theory Δ ∪ T where (...) T results from adding, removing or flipping a literal in S. We present two results relating to the time and space complexity of compiling propositional theories into sd-DNNF. First, we show that if a conjunctive normal form (CNF) has a bounded treewidth, then it can be compiled into an sd-DNNF in time and space which are linear in its size. Second, we show that sd-DNNF is a strictly more space efficient representation than Free Binary Decision Diagrams (FBDDs). Finally, we discuss some applications of the counting results to truth maintenance systems, belief revision, and model-based diagnosis. (shrink)

On se propose de penser enfin et de retrouver le sens du Göttliche heideggerien en tant que tel, nettement distingué du seul Dieu et du Sacré, dans la constellation des quatre du Geviert. Nous considérons alors le divin dans les premiers travaux sur Hölderlin, où Heidegger reconnaît déjà sa présence dans la pensée sur les mortels, la terre, le ciel et le monde, et dans leurs relations respectives qui restaient encore à élucider. Par la suite, le travail sur le rassemblement (...) qui caractérise la Kehre permettra à Heidegger de déterminer le divin comme don au sein du Sacré. A partir de là, nous assistons à un développement pluriel du sens du divin selon sa position en vis-à-vis et auprès de chacun des quatre, puis dans l’histoire destinale et au sein de la différence et du cercle rassemblant : la quadrature du cercle en tant qu’énigme-mystère s’avère alors comme lieu de rencontre du divin en tant que l’Inconnu.This paper aims at finally ponder about and find some meaning in the Heidegerrian Göttliche as such, clearly distinguished from the mere God or the Holy, in the constellation of the Geviert’s four elements. We consider the divine in the first work done on Hölderlin where Heidegger detects its presence in the thought dealing with mortals, earth, heaven and the world, and in their several respective relationships he was further to elucidate. Later, the work done on the gathering which marks the Kehre enables Heidegger to determine the divine as a gift from within the Holy. We then find a multiple development of the divine’s meaning through its position over-against and along each one of the four, then in destinal history and within the difference and the gathering circle : the four sidedness of the circle as a riddle turns out to be the meeting place for the divine as the unknown. (shrink)

On se propose de penser enfin et de retrouver le sens du Göttliche heideggerien en tant que tel, nettement distingué du seul Dieu et du Sacré, dans la constellation des quatre du Geviert. Nous considérons alors le divin dans les premiers travaux sur Hölderlin, où Heidegger reconnaît déjà sa présence dans la pensée sur les mortels, la terre, le ciel et le monde, et dans leurs relations respectives qui restaient encore à élucider. Par la suite, le travail sur le rassemblement (...) qui caractérise la Kehre permettra à Heidegger de déterminer le divin comme don au sein du Sacré. À partir de là, nous assistons à un développement pluriel du sens du divin selon sa position en vis-à-vis et auprès de chacun des quatre, puis dans l'histoire destinale et au sein de la différence et du cercle rassemblant : la quadrature du cercle en tant qu'énigme-mystère s'avère alors comme lieu de rencontre du divin en tant que l'Inconnu. This paper aims at finally ponder about and find some meaning in the Heidegerrian Göttliche as such, clearly distinguished from the mere God or the Holy, in the constellation of the Geviert's four elements. We consider the divine in the first work done on Hölderlin where Heidegger detects its presence in the thought dealing with mortals, earth, heaven and the world, and in their several respective relationships he was further to elucidate. Later, the work done on the gathering which marks the Kehre enables Heidegger to determine the divine as a gift from within the Holy. We then find a multiple development of the divine's meaning through its position over-against and along each one of the four, then in destinai history and within the difference and the gathering circle : the four sidedness of the circle as a riddle turns out to be the meeting place for the divine as the unknown. (shrink)

The purpose of this article is twofold. It first seeks to prove that the notion of facticity in Heidegger’s work saw a major change after Being and Time. While several studies did deal with facticity as it appeared before the magnus opus and show the influence it had on the latter’s development, hardly any have dealt with what happens to facticity after Sein und Zeit. This is mostly because facticity, as it imploded, took on different names which fall under the (...) heading of ground-attunements. Secondly, I will show the ambivalent character of this new facticity, where many essential notions, such as thrownness, truth, attunement and guilt, shifted meanings, sometimes almost imperceptibly or surreptitiously. I will show that this ambivalence comes from the fact that the shift in question allowed for an opening of facticity while at the same time bringing in restrictive limits, and thus a closing-off of certain essential issues. This has left several adumbrated questions, such as responsibility, in abeyance. (shrink)

This paper analyzes how national institutions impact corporate social responsibility practices for small- and medium-sized enterprises in the food-processing industries of France and Morocco. In this study, CSR practices are defined around two main dimensions: corporate performance and the CSR approach. Qualitative data were collected during semi-structured interviews with SME managers in charge of CSR issues. We then performed a content analysis. Our study shows that there is a distinct difference between the CSR practices adopted by SMEs in France and (...) Morocco. Indeed, the findings suggest that under the rule-based governance system of France, most SMEs view CSR as an economic tool and it is adopted as an opportunity-seeking perspective anchored in the search for global performance. The findings also show that under the relationship-based governance system of Morocco, SMEs mainly see CSR from a constraint-reducing perspective. However, some Moroccan SMEs have begun to see the economic opportunities of CSR, especially in accessing foreign markets. (shrink)

There is a distinct lack of research into the relationship between corporate governance and corporate social responsibility (CSR) in the banking sector. This paper fills the gap in the literature by examining the impact of corporate governance, with particular reference to the role of board of directors, on the quality of CSR disclosure in US listed banks’ annual reports after the US sub-prime mortgage crisis. Using a sample of large US commercial banks for the period 2009–2011 and controlling for audit (...) committee characteristics, board meeting frequency, and banks’ profitability, size and risk, we find evidence that board independence and board size, the two board characteristics usually associated with the protection of shareholder interests, are positively related to CSR disclosure. This indicates that, with regard to CSR disclosure, more independent boards of directors and larger boards are the internal corporate governance mechanisms which promote both shareholders’ and other stakeholders’ interests. Contrary to our expectations, CEO duality also impacts positively on CSR disclosure. From an agency-theoretical viewpoint, this suggests that powerful CEOs may promote transparency about banks’ CSR activities for their private benefits. While this could indicate that powerful CEOs are under particular pressure to appease stakeholders’ concerns that they might abuse their power by providing a high degree of CSR disclosure, it could also be a sign of managerial risk aversion or managers’ private reputational concerns. (shrink)

Being in a romantic relationship is characterized by a high degree of intimacy and affective involvement. Affective behavior indicates the emotional content in couple interactions and therefore promotes an understanding of the evolution of romantic relationships. When couples are also parents, their affective behavior reflects their romantic and coparental bonds. In this paper, we present an observation of parent couples’ affective behavior during a coparenting conflict discussion task to document whether and how much it improved during couple therapy. Two contrasting (...) cases of affective behavior change are included. Observational coding of affective behavior within pre- and post-intervention coparenting conflict discussion tasks was carried out to compute means and CIs for each partner in both cases. In addition, the partners’ coparental and romantic satisfaction were evaluated through validated self-report questionnaires in pre- and post-intervention assessments; this helped document whether the partners’ coparental and romantic satisfaction were dissimilar between the two cases. Finally, a clinical analysis of both cases was realized with the contribution of the therapists to investigate possible differences within therapy sessions. Statistical analyses revealed negative means of affective behavior for couple A in the pre-intervention assessment and positive means in the post-intervention assessment. Partners from couple B had negative means of affective behavior in the pre- and post-intervention assessments. Results concerning coparental and romantic satisfaction differed: Couple A’s coparental satisfaction slightly increased and the romantic satisfaction somewhat decreased, whereas couple B’s coparental satisfaction remained stable and the romantic satisfaction slightly increased between the pre- and post-intervention assessments. The clinical analysis revealed that the interactional quality of couple A slightly improved within therapy sessions and that both partners succeeded in working together as coparents, notwithstanding their romantic distress. Couple B conveyed coparental distress and exhibited poor interactional quality throughout therapy sessions (e.g., repeated criticism and contempt). This study contributes to enriching the more traditional empirical research methods in the field of couple psychotherapy, as it takes into account microlevel affective changes within parent couples’ interactions in addition to self-reported data. Furthermore, the analysis of therapy sessions supports the importance of working with affective behavior in couple therapy. (shrink)

This paper analyzes how national institutions impact corporate social responsibility practices for small- and medium-sized enterprises in the food-processing industries of France and Morocco. In this study, CSR practices are defined around two main dimensions: corporate performance and the CSR approach. Qualitative data were collected during semi-structured interviews with SME managers in charge of CSR issues. We then performed a content analysis. Our study shows that there is a distinct difference between the CSR practices adopted by SMEs in France and (...) Morocco. Indeed, the findings suggest that under the rule-based governance system of France, most SMEs view CSR as an economic tool and it is adopted as an opportunity-seeking perspective anchored in the search for global performance. The findings also show that under the relationship-based governance system of Morocco, SMEs mainly see CSR from a constraint-reducing perspective. However, some Moroccan SMEs have begun to see the economic opportunities of CSR, especially in accessing foreign markets. (shrink)

Brain–machine interfaces are systems that allow the control of a device such as a robot arm through a person’s brain activity; such devices can be used by disabled persons to enhance their life and improve their independence. This paper is an extended version of a work that aims at discriminating between left and right imagined hand movements using a support vector machine classifier to control a robot arm in order to help a person to find an object in the environment. (...) The main focus here is to search for the best features that describe efficiently the electroencephalogram data during such imagined gestures by comparing two feature extraction methods, namely the continuous wavelet transform and the empirical modal decomposition, combined with the principal component analysis that were fed through a linear and radial basis function kernel SVM classifier. The experimental results showed high performance achieving an average accuracy across all the subjects of 92.75% with an RBF kernel SVM classifier using CWT and PCA compared to 80.25% accuracy obtained with EMD and PCA. The proposed system has been implemented and tested using data collected from five male subjects and it enabled the control of the robot arm in the right and the left direction. (shrink)

Darwiche and Pearl’s seminal 1997 article outlined a number of baseline principles for a logic of iterated belief revision. These principles, the DP postulates, have been supplemented in a number of alternative ways. Most suggestions have resulted in a form of ‘reductionism’ that identifies belief states with orderings of worlds. However, this position has recently been criticised as being unacceptably strong. Other proposals, such as the popular principle (P), aka ‘Independence’, characteristic of ‘admissible’ operators, remain commendably more modest. In this (...) paper, we supplement the DP postulates and (P) with a number of novel conditions. While the DP postulates constrain the relation between a prior and a posterior conditional belief set, our new principles notably govern the relation between two posterior conditional belief sets obtained from a common prior by different revisions. We show that operators from the resulting family, which subsumes both lexicographic and restrained revision, can be represented as relating belief states associated with a ‘proper ordinal interval’ (POI) assignment, a structure more fine-grained than a simple ordering of worlds. We close the paper by noting that these operators satisfy iterated versions of many AGM era postulates, including Superexpansion, that are not sound for admissible operators in general. (shrink)

We review the definition of the Full Bayesian Significance Test (FBST), and summarize its main statistical and epistemological characteristics. We review also the Abstract Belief Calculus (ABC) of Darwiche and Ginsberg, and use it to analyze the FBST’s value of evidence. This analysis helps us understand the FBST properties and interpretation. The definition of value of evidence against a sharp hypothesis, in the FBST setup, was motivated by applications of Bayesian statistical reasoning to legal matters where the sharp hypotheses were (...) defendants statements, to be judged according to the Onus Probandi juridical principle. (shrink)

This paper presents the model of ‘bounded revision’ that is based on two-dimensional revision functions taking as arguments pairs consisting of an input sentence and a reference sentence. The key idea is that the input sentence is accepted as far as (and just a little further than) the reference sentence is ‘cotenable’ with it. Bounded revision satisfies the AGM axioms as well as the Same Beliefs Condition (SBC) saying that the set of beliefs accepted after the revision does not depend (...) on the reference sentence (although the posterior belief state does depend on it). Bounded revision satisfies the Darwiche–Pearl (DP) axioms for iterated belief change. If the reference sentence is fixed to be a tautology or a contradiction, two well-known one-dimensional revision operations result. Bounded revision thus naturally fills the space between conservative revision (also known as natural revision) and moderate revision (also known as lexicographic revision). I compare this approach to the two-dimensional model of ‘revision by comparison’ investigated by Fermé and Rott (Artif Intell 157:5–47, 2004 ) that satisfies neither the SBC nor the DP axioms. I conclude that two-dimensional revision operations add substantially to the expressive power of qualitative approaches that do not make use of numbers as measures of degrees of belief. (shrink)

Generalisations of theory change involving arbitrary sets of wffs instead of belief sets have become known as base change. In one view, a base should be thought of as providing more structure to its generated belief set, and can be used to determine the theory change operation associated with a base change operation. In this paper we extend a proposal along these lines by Meyer et al. We take an infobase as a finite sequence of wffs, with each element in (...) the sequence being seen as an independently obtained bit of information, and define appropriate infobase change operations. The associated theory change operations satisfy the AGM postulates for theory change. Since an infobase change operation produces a new infobase, it allows for iterated infobase change. We measure iterated infobase change against the postulates proposed by Darwiche et al. and Lehmann. (shrink)

Belief revision theory aims to describe how one should change one’s beliefs when they are contradicted by newly input information. The guiding principle of belief revision theory is to change one’s prior beliefs as little as possible in order to maintain consistency with the new information. Learning theory focuses, instead, on learning power: the ability to arrive at true beliefs in a wide range of possible environments. The goal of this paper is to bridge the two approaches by providing a (...) learning theoretic analysis of the learning power of belief revision methods proposed by Spohn, Boutilier, Darwiche and Pearl, and others. The results indicate that learning power depends sharply on details of the methods. Hence, learning power can provide a well-motivated constraint on the design and implementation of concrete belief revision methods. (shrink)

Close connections between probability theory and the theory of belief change emerge if the codomain of probability functions is extended from the real-valued interval [0, 1] to a hyperreal interval with the same limits. Full beliefs are identified as propositions with a probability at most infinitesimally smaller than 1. Full beliefs can then be given up, and changes in the set of full beliefs follow a pattern very close to that of AGM revision. In this contribution, iterated revision is investigated. (...) The iterated changes in the set of full beliefs generated by repeated revisions of a hyperreal probability function can, semantically, be modelled with the same basic structure as the sphere models of belief change theory. The changes on the set of full beliefs induced by probability revision satisfy the Darwiche–Pearl postulates for iterated belief change. (shrink)

In this paper we study changes of beliefs in a ranking-theoretic setting using non-extremal implausibility thresholds for belief. We represent implausibilities as ranks and introduce natural rank changes subject to a minimal change criterion. We show that many of the traditional AGM postulates for revision and contraction are preserved, except for the postulate of Preservation which is invalid. The diagnosis for belief contraction is similar, but not exactly the same. We demonstrate that the one-shot versions of both revision and contraction (...) can be represented as revisions based on semiorders, but in two subtly different ways. We provide sets of postulates that are sound and complete in the sense that they allow us to prove representation theorems. We show that, and explain why, the classical duality between revision and contraction, as exhibited by the Levi and Harper identities, is partly broken by threshold-based belief changes. We also study the logic of iterated threshold-based revision and contraction. The traditional Darwiche-Pearl postulates for iterated revision continue to hold, as well as two additional postulates that characterize ranking-based revision as a restricted `improvement' operator. We investigate the dual notion of iterated threshold-based belief contraction and provide a new set of postulates for it, characterizing contraction as a restricted 'degrading' operator. (shrink)

This article provides a discussion of the principle of transmission of evidential support across entailment from the perspective of belief revision theory in the AGM tradition. After outlining and briefly defending a small number of basic principles of belief change, which include a number of belief contraction analogues of the Darwiche-Pearl postulates for iterated revision, a proposal is then made concerning the connection between evidential beliefs and belief change policies in rational agents. This proposal is found to be suffcient to (...) establish the truth of a much-discussed intuition regarding transmission failure. (shrink)

The axiom of recovery, while capturing a central intuition regarding belief change, has been the source of much controversy. We argue briefly against putative counterexamples to the axiom—while agreeing that some of their insight deserves to be preserved—and present additional recovery-like axioms in a framework that uses epistemic states, which encode preferences, as the object of revisions. This makes iterated revision possible and renders explicit the connection between iterated belief change and the axiom of recovery. We provide a representation theorem (...) that connects the semantic conditions we impose on iterated revision and our additional syntactical properties. We show interesting similarities between our framework and that of Darwiche–Pearl (Artificial Intelligence 89:1–29 1997). In particular, we show that intuitions underlying the controversial (C2) postulate are captured by the recovery axiom and our recovery-like postulates (the latter can be seen as weakenings of (C2)). We present postulates for contraction, in the same spirit as the Darwiche–Pearl postulates for revision, and provide a theorem that connects our syntactic postulates with a set of semantic conditions. Lastly, we show a connection between the contraction postulates and a generalisation of the recovery axiom. (shrink)

In this paper we propose a conditional logic called IBC to represent iterated belief revision systems. We propose a set of postulates for iterated revision which are a small variant of Darwiche and Pearl''s ones. The conditional logic IBC has a standard semantics in terms of selection function models and provides a natural representation of epistemic states. We establish a correspondence between iterated belief revision systems and IBC-models. Our representation theorem does not entail Gärdenfors'' Triviality Result.

In this paper we (Laura Giordano, Nicola Olivetti and myself) propose a conditional logic to represent iterated belief revision systems. We propose a set of postulates for belief revision which are a small variant of Darwiche and Pearl's ones.The resulting conditional logic has a standard semantics in terms of selection function models, and provides a natural representation of epistemic states. A Representation Theorem establishes a correspondence between iterated belief revision systems and conditional models. Our Representation Theorem does not entail Gärdenfors' (...) Triviality Result. (shrink)

Two of the major problems in AGM-style belief revision, namely the difficulties in accounting for iterated change and for Ramsey test conditionals, have satisfactory solutions in descriptor revision. In descriptor revision, the input is a metalinguistic sentence specifying the success condition of the operation. The choice mechanism selects one of the potential outcomes in which the success condition is satisfied. Iteration of this operation is unproblematic. Ramsey test conditionals can be introduced without giving rise to the paradoxical results that they (...) generate in other systems. In addition to standard Ramsey test conditionals, a more general variant of epistemic conditionals is defined, representing statements of the form ”if the belief state is changed to satisfy condition A then it will satisfy condition B”. An axiomatic characterization of such descriptor conditionals is presented. It is related in intricate ways to the KLM postulates for cumulative reasoning. (shrink)

Discussions of the issue of iterated belief revision are commonly accompanied by the presentation of three “concrete” operators: natural, restrained and lexicographic. This raises a natural question: What is so distinctive about these three particular methods? Indeed, the common axiomatic ground for work on iterated revision, the AGM and Darwiche-Pearl postulates, leaves open a whole range of alternative proposals. In this paper, we show that it is satisfaction of an additional principle of “Independence of Irrelevant Alternatives”, inspired by the literature (...) on Social Choice, that unites and sets apart our three “elementary” revision operators. A parallel treatment of iterated belief contraction is also given, yielding a family of elementary contraction operators that includes, besides the well-known “conservative” and “moderate” operators, a new contraction operator that is related to restrained revision. (shrink)