Marie-Christine Lagasquie-Schiex

Paul Sabatier University - Toulouse III | UPS Toulouse · Computer science department

In our paper [17], we have proposed a logical encoding of argumentation frameworks with higher-order interactions (i.e. attacks or supports whose targets are arguments or other attacks or supports) with an evidential interpretation for supports, such frameworks are called REBAF. With this encoding, we are able to characterize the semantics of REBAF...

Computation and decision problems related to argumentation frameworks with higher-order attacks have not received a lot of attention so far. This paper is a step towards these issues. First, it provides a labelling counterpart for the structure semantics of Recursive Argumentation Frameworks (RAF). Second, it investigates the complexity of decision...

This paper explores the computation of explanations in the specific context of abstract argumentation. The explanations that we define are designed to be visual, in the sense that they take the form of subgraphs of the argumentation graph. Moreover, these explanations rely on the modular aspects of abstract argumentation semantics and can consequen...

Argumentation has become an essential tool in AI, allowing the representation of knowledge with only a set of arguments and a binary relation between arguments, the attack relation. Since the seminal work presented in 1995 by Dung, many extensions have been proposed in order to enrich this very simple framework by the addition of a second type of i...

In our paper [13], we have proposed a logical encoding of argumentation frameworks with higher-order interactions (i.e. attacks or supports whose targets are arguments or other attacks or supports) with an evidential meaning for supports, such frameworks are called REBAF. With this encoding, we are able to characterize the semantics of REBAF under...

The purpose of this work is to study a generalisation of Dung’s abstract argumentation frameworks that allows representing recursive attacks, that is, a class of attacks whose targets are other attacks. We do this by developing a theory of argumentation where the classic role of attacks in defeating arguments is replaced by a subset of them, which...

Computation and decision problems related to argumentation frameworks with higher-order attacks have not received a lot of attention so far. This paper is a step towards these issues: first, it provides a labelling counterpart for the structure semantics of Recursive Argumentation Frameworks (RAF); second, it investigates the complexity of decision...

We propose a logical encoding of argumentation frameworks with higher-order interactions (i.e. attacks/supports whose targets are arguments or other attacks/supports) with an evidential meaning for supports. Our purpose is to separate the logical expression of the meaning of an attack or an evidential support (simple or higher-order) from the logic...

This chapter is devoted to logical models for reasoning from contradictory information. It deals with methods, such as argumentation, that refrain from giving up any piece of information (by contrast with revision, as discussed in chapter “Main Issues in Belief Revision, Belief Merging and Information Fusion” of this volume). The baseline is to get...

In 1995, in his seminal paper introducing the abstract argumentation framework, Dung has also established the first relationship between this framework and a logical framework (in this case: logic programming). Since that time, a lot of work have pursued this path, proposing different definitions, uses and exhibiting distinct relationships between...

Computing acceptability semantics of abstract argumentation frameworks is receiving increasing attention. Large-scale instances, with a clustered structure, have shown particularly difficult to compute. This paper presents a distributed algorithm, AFDivider, that enumerates the acceptable sets under several labelling-based semantics. This algorithm...

This chapter aims at providing logical encodings for translating interactions in an argumentation graph themselves into propositional knowledge bases. This translation will be used for identifying or redefining some properties of argumentation graphs. The graphs we consider are used to formalize abstract argumentation with at least two different ki...

This article proposes a complete framework for handling the dynamics of an abstract argumentation system. This frame can encompass several belief bases under the form of several argumentation systems, more precisely it is possible to express and study how an agent who has her own argumentation system can interact on a target argumentation system (t...

In the context of bipolar argumentation (argumentation with two kinds of interaction, attacks and supports), we present an axiomatic approach for taking into account a special interpretation of the support relation, the necessary support. We propose constraints that should be imposed to a bipolar argumentation system using this interpretation. Some...

The purpose of this paper is to describe some results of the LELIE project, that are a contribution of Artificial Intelligence to a special domain: the analysis of the risks due to poorly written technical documents. This is a multidisciplinary contribution since it combines natural language processing with logical satisfiability checking. This pap...

GRAFIX is a graphical tool for handling abstract argumentation graphs. GRAFIX allows the edition and the presentation of argumentation graphs (or sets of graphs), and the execution of some predefined treatments (called server treatments) on the current graph(s) such as, for instance, computing various acceptability semantics, or computing the stren...

This paper defines a new framework for dynamics in argumentation. In this framework, an agent can change an argumentation system (the target system) in order to achieve some desired goal. Changes consist in addition/removal of arguments or attacks between arguments and are constrained by theagent's knowledge encoded by another argumentation system....

Dung's argumentation framework has been extended to consider preferences over arguments or over attacks, in a qualitative or in a quantitative way. In this paper, we investigate the relationships between preferences over arguments and preferences over attacks. We give conditions on the definition of preferences over attacks from preferences over ar...

In the literature, enforcement consists in changing an argumentation system in order to force it to accept a given set of arguments. In this paper, we extend this notion by allowing incomplete information about the initial argumentation system. Generalized enforcement is an operation that maps a propositional formula describing a system and a propo...

In the literature, enforcement consists in changing an argumentation system in order to force it to accept a given set of arguments. In this paper, we extend this notion by allowing incomplete information about the initial argumentation system. Generalized enforcement is an operation that maps a propositional formula describing a system and a propo...

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...

Practical reasoning (PR), which is concerned with the generic question of what to do, is generally seen as a two steps process: (1) deliberation, in which an agent decides what state of affairs it wants to reach – that is, its desires; and (2) means-ends reasoning, in which the agent looks for plans for achieving these desires. The agent’s intentio...

In this paper, we address the problem of merging argumentation systems (AS) in a multi-agent setting. Each agent's system may be built from different sets of arguments and/or different interactions between these arguments. The merging process must lead to solve conflicts between the agents and to identify ASs representing the knowledge of the group...

This article studies a specific kind of change in an argumentation system: the removal of an argument and its interactions. We illustrate this operation in a legal context and we establish the conditions to obtain some desirable properties when removing an argument.

Different abstract argumentation frameworks have been used for various applications within multi-agents systems. Among them, bipolar frameworks make use of both attack and support relations between arguments. However, there is no single interpretation of the support, and the handling of bipolarity cannot avoid a deeper analysis of the notion of sup...

We consider argumentation systems taking into account several attack relations of different strength. We focus on the impact of various strength attacks on the semantics of such systems, and particularly on the decision problem of credulous acceptance: namely, focussing on one particular argument, a classical issue is to compute a proof, under the...

There already exist some links between argumentation and game theory. For instance, dynamic games can be used for simulating interactions between agents in an argumentation process. In this paper, we establish a new link between these domains in a static framework: we show how an argumentation framework can be translated into a CP-Boolean game and...

In this paper, we address the problem of change in an abstract argumentation system. We focus on a particular change: the addition of a new argument which interacts with previous arguments. We study the impact of such an addition on the outcome of the argumentation system, more particularly on the set of its extensions. Several properties for this...

Bipolar argumentation frameworks enable to rep-resent two kinds of interaction between argu-ments: support and conflict. In this paper, we turn a bipolar argumentation framework into a "meta-argumentation" framework where conflicts occur between sets of arguments, characterized as coalitions of supporting arguments. So, Dung's well-known semantics...

We consider argumentation systems with several attack relations of different strength. We focus on the impact of various strength attacks on the semantics of such systems. First, we refine the classical notion of defence, by comparing the strength of an attack with the strength of a counter-attack. Then, we propose different ways to compare defende...

There already exist some links between argumentation and game theory. For instance, dynamic games can be used for simulating interactions between agents in an argumentation process. In this paper, we establish a new link between these domains in a static framework: we show how an argumentation framework can be translated into a CP-Boolean game and...

LNCS 4724, http://dx.doi.org/10.1007/978-3-540-75256-1_65 Boolean games are a logical setting for representing static 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 them controls a set of propositional variables and has a specific goal ex...

In most existing argumentation systems, only one kind of interaction is considered between arguments. It is the so-called attack relation. However, recent studies on argumentation [23, 34, 35, 4] have shown that another kind of interaction may exist between the arguments. Indeed, an argument can attack another argument, but it can also support anot...

Game theory is a widely used formal model for studying strategical interactions between agents. Boolean games (Harrenstein, Logic in conflict, PhD thesis, 2004; Harrenstein et al., Theoretical Aspects of Rationality and Knowledge, pp. 287–298, San Francisco Morgan Kaufmann, 2001) yield a compact representation of 2-player zero-sum static games with...

In this article, we propose a survey of the use of bipolarity in argumentation frameworks. On the one hand, the notion of bipolarity relies on the presence of two kinds of entities that have a diametrically opposed nature and that represent repellent forces (a positive entity and a negative entity). The notion exists in various domains (for example...

LNCS 4099, http://dx.doi.org/10.1007/978-3-540-36668-3_7 Boolean games, introduced by [15,14], allow for expressing compactly two-players zero-sum static games with binary preferences: an agent’s strategy consists of a truth assignment of the propositional variables she controls, and a player’s preferences is expressed by a plain propositional form...

Practicalreasoning (PR),which is concerned withthe generic ques- tion of what to do, is generally seen as a two steps process: (1) de- liberation , in which an agent decides what state of affairs it wants to reach -that is, its desires ; and (2) means-ends reasoning , in which the agent looks for plans for achieving these desires. A desire is jus-...

In this paper, we address the problem of revising a Dung-style abstract argumentation system, when we add a new argument which interacts with one previous argument. We study the impact of such an addition on the outcome of the argumentation system, more particularly on the set of its extensions. Different kinds of revision are defined according to...

Boolean games are a logical setting for representing strategic games in a succinct way, taking advantage of the expressive power and conciseness of proposi-tional logic. A Boolean game consists of a set of players, each of whom controls a set of propositional variables and has a specific goal expressed by a proposi-tional formula. We show here that...

In this paper, the problem of deriving sensible information from a collection of argumentation systems coming from different agents is addressed. The underlying argumentation theory is Dung's one: each argumentation system gives both a set of arguments and the way they interact (i.e., attack or non-attack) according to the corresponding agent. The...

We consider bipolar argumentation frameworks, which extend Dung's argumentation frameworks by handling two independent kinds of interaction between arguments, attack and support. In this bipolar context, we propose new semantics for coping with the problem of controversial arguments (arguments which indirectly attack and indirectly defend a same ar...

Game theory is a widely used formal model for studying strategical interactions between agents. Boolean games [8] are two players, zero-sum static games where players’ utility functions are binary and described by a single propositional formula, and the strategies available to a player consist of truth assignments to each of a given set of proposit...

In this paper, we extend the abstract argumentation framework proposed by [1] in order to take into account two kinds of interaction between arguments: a positive interaction (an argument can help, support another argument) and a negative interaction (an argument can attack another argument). In this new abstract argumentation framework, called a b...

Argumentation is based on the exchange and valuation of interacting arguments, followed by the selection of the most acceptable of them (for example, in order to take a decision, to make a choice). Starting from the framework proposed by Dung in 1995, our purpose is to introduce \graduality" in the selection of the best arguments, i.e. to be able t...

In this paper, we extend the basic abstract argumentation framework proposed by Dung, by taking into account two independent kinds of interaction between arguments: a defeat relation and a support relation. In that new framework, called a bipolar argumentation framework, we focus on the concept of acceptability and propose new semantics defined fro...

In this paper, we address the problem of deriving sensible in- formation from a collection of argumentation systems coming from different agents. A general framework for merging ar- gumentation systems from Dung's theory of argumentation is presented. Each argumentation system gives both a set of ar- guments and the way they interact (i.e. attack o...

This chapter focuses on the gradual handling of defeat interactions among arguments, within the argumentation frameworks. Argumentation is based on the exchange and evaluation of interacting arguments. Argumentation frameworks provide a unifying and powerful tool for the study of many formal systems developed for common-sense reasoning, as well as...

The argumentation is based on exchange and valua-tion of arguments interacting, then on the definition of accepted arguments (or sets of arguments) w.r.t. the proposed valuation. In this paper, using the ar-gumentation system of [Dun95] and the valuations proposed in [CLS02a], we introduce graduality in the acceptability of arguments.

Dung's abstract framework for argumentation enables a study of the interactions between arguments based solely on an ``attack'' binary relation on the set of arguments. Various ways to solve conflicts between contradictory pieces of information have been proposed in the context of argumentation, nonmonotonic reasoning or logic programming, and can...

Dung's abstract framework for argumenta- tion enables a study of the interactions be- tween arguments based solely on an "attack" binary relation on the set of arguments. Var- ious ways to solve conflicts between contra- dictory pieces of information have been pro- posed in the context of argumentation, non- monotonic reasoning or logic programming...

The purpose of this paper is to outline various results regarding the computational complexity and the algorithms of nonmonotonic entailment in different coherence‐based approaches. Starting from a (non necessarily consistent) belief base E and a pre‐order on E, we first present different mechanisms for selecting preferred consistent subsets. Then...

Introduction We focus on coherence-based approaches to non-monotonic reasoning. These approaches handle syntactical belief bases equipped with symbolic ordering structures and rely upon classical logic. The belief base, a finite set of propositional formulae, is considered syntactically, as in (Nebel 1991): each belief is a distinct piece of inform...

The purpose of this paper is to provide a comparative study of non-monotonic syntax-based consequence relations, from different points of view. Starting from a (not necessarily consistent) belief base E and a pre-ordering on E, we first remind different mechanisms for selecting preferred consistent subbases in syntax-based approaches. Then, we pres...

The purpose of this paper is to outline various results regarding the computational complexity of nonmonotonic entailment in different syntax-based approaches. Starting from a (non necessarily consistent) belief base E and a pre-ordering on E, we first remind different mechanisms for selecting preferred consistent subsets in syntax-based approaches...

Le domaine abordé ici est le raisonnement non-monotone et plus particulièrement les formalismes modélisant la capacité de déduction d'un tel raisonnement. Ce travail ne porte pas sur le développement de nouveaux formalismes de raisonnement non-monotone, mais propose une étude comparative dans un cadre unificateur. A partir d'une base de croyances,...

In this paper we propose semantics for acceptablity in partial argumentation frameworks (PAF). The PAF is an extension of Dung’s argumentation framework and has been introduced in [1] for merging argumentation frameworks. It consists in adding a new interaction between arguments representing the ignorance about the existence of an attack. The propo...

Résumé : Dans cet article, nous proposons une extension des jeux booléens étudiés par [7, 5] qui devrait permettre à terme de modéliser de manière compacte les préférences des joueurs dans les jeux statiques. Cette extension propose des jeux booléens à n joueurs et à somme non nulle, et en étudie les propriétés computa-tionnelles. Nous montrons ens...