Using ASP with recent extensions for causal explanations

We examine the practicality for a user of using Answer Set Programming (ASP) for representing logical formalisms. We choose as an example a formalism aiming at capturing causal explanations from causal information. We provide an implementation, showing the naturalness and relative efficiency of this translation job. We are interested in the ease for writing an ASP program, in accordance with the claimed ``declarative'' aspect of ASP. Limitations of the earlier systems (poor data structure and difficulty in reusing pieces of programs) made that in practice, the ``declarative aspect'' was more theoretical than practical. We show how recent improvements in working ASP systems facilitate a lot the translation, even if a few improvements could still be useful

Using Answer Set Programming for pattern mining

Serial pattern mining consists in extracting the frequent sequential patterns from a unique sequence of itemsets. This paper explores the ability of a declarative language, such as Answer Set Programming (ASP), to solve this issue efficiently. We propose several ASP implementations of the frequent sequential pattern mining task: a non-incremental and an incremental resolution. The results show that the incremental resolution is more efficient than the non-incremental one, but both ASP programs are less efficient than dedicated algorithms. Nonetheless, this approach can be seen as a first step toward a generic framework for sequential pattern mining with constraints.Comment: Intelligence Artificielle Fondamentale (2014

Utiliser la programmation par ensembles réponses pour de petits problèmes

Session "Posters"National audienceEn traduisant en programmation par ensembles réponses deux devinettes classiques, nous illustrons la puissance et certaines limites des systèmes actuels. Il s'agit de les traduire d'une façon pas trop ad-hoc, tirant profit de l'aspect déclaratif de ce type de programmation. On n'est pas loin de cet objectif affiché, mais il reste des progrès à faire pour les systèmes existant. Nous suggérons quelques pistes: l'intégration de réelles listes, une meilleure intégration entre instantiateur et solveur, permettant au moins de détecter les cas où le premier suffit, une déclaration de prédicats satisfaisant une loi d'inertie, une déclaration de prédicats "intermédiaires''

A formalism for causal explanations with an Answer Set Programming translation

International audienceWe examine the practicality for a user of using Answer Set Programming (ASP) for representing logical formalisms. Our example is a formalism aiming at capturing causal explanations from causal information. We show the naturalness and relative efficiency of this translation job. We are interested in the ease for writing an ASP program. Limitations of the earlier systems made that in practice, the ``declarative aspect'' was more theoretical than practical. We show how recent improvements in working ASP systems facilitate the translation

Arguments using ontological and causal knowledge (JIAF 2013)

National audienceWe investigate an approach to reasoning about causes through argumentation. We consider a causal model for a physical system, and look for arguments about facts. Some arguments are meant to provide explanations of facts whereas some challenge these explanations and so on. At the root of argumentation here, are causal links ({A_1, ... ,A_n} causes B) and ontological links (o_1 is_a o_2). We present a system that provides a candidate explanation ({A_1, ... ,A_n} explains {B_1, ... ,B_m}) by resorting to an underlying causal link substantiated with appropriate ontological links. Argumentation is then at work from these various explaining links. A case study is developed: a severe storm Xynthia that devastated part of France in 2010, with an unaccountably high number of casualties.Nous décrivons l'utilisation d'un systéme logique de raisonnement á partir de données causales et ontologiques dans un cadre argumentatif. Les données consistent en liens causaux ({{A_1,...,A_n} cause B) et ontologiques (o_1 est_un} o_2). Le système en déduit des liens explicatifs possibles ({A_1, ... ,A_n} explique {B_1, ... ,B_m}). Ces liens explicatifs servent ensuite de base á un système argumentatif qui fournit des explications possibles. Un exemple inspiré de la tempête Xynthia, laquelle a provoqué un trop grand nombre de victimes par rapport aux conditions purement météorologiques, illustre une utilisation de notre système

Preferential Entailments, Extensions and Reductions of The Vocabulary

A preferential entailment is defined by a binary relation, or «preference relation», either among interpretations (or models) or among «states» which are «copies of interpretations». Firstly, we show how an extension of the vocabulary allows to express any preferential entailment as a preferent- ial entailment without state. Secondly, by reducing the vocabulary, we show how to express some preferential entailments in a smaller language. This second method works only for particular preferential entailments, including the widely used circumscription. For our purpose, we need to make precise the operations of extension or reduction of the vocabulary, which may have applications in other domains. We study which properties of an inference operation are preserved by the reduction and extension of the vocabulary introduced in this text. We provide examples of applications of our results. These applications are all related to various kinds of circumscriptions, because this suffices to provide examples of useful and non trivial results. Moreover, our study shows that many preferential entailments of the two kinds may be easily expressed in terms of circumscripti- on. All along the text, we take great care in providing constructive definitions, and to keep these constructions as simple and natural as possible

Pointwise circumscription is equivalent to predicate completion (sometimes)

International audienceTwo ways of minimizing positive information are predicate completion, which comes from logic programming theory, and circumscription, which is one of the best known methods of non-monotonic reasoning. Here, it is shown that, under certain hypothesis, there is equivalence between predicate completion and a special kind of circumscription

Forgetting literals with varying propositional symbols

International audienceRecently, the old logical notion of forgetting propositional symbols (or reducing the logical vocabulary) has been generalized to a new notion: forgetting literals. The aim was to help the automatic computation of various formalisms which are currently used in knowledge representation. We extend here this notion, by allowing propositional symbols to vary while forgetting literals. The definitions are not really more complex than for literal forgetting without variation. We describe the new notion, on the syntactical and the semantical side. Then, we show how to apply it to the computation of circumscription. This computation has been done before with standard literal forgetting, but here we show how introducing varying propositional symbols simplifies significantly the computation. We revisit a fifteen years old result about computing circumscription, showing that it can be improved in the same way. We provide hints in order to apply this forgetting method also to other logical formalisms