The project AMANDE was supported by the French National Research Agency (ANR) (2013-2018).
Objective : Theoretical foundations for the aggregation of arguments coming from multiple sources
Debating and exchanging arguments is a fundamental human activity, studied for a long time. But considering that it is already difficult to evaluate which of two debaters was the most convincing, how can we handle debates where participants can be counted in dozens, even more? Online deliberation platforms makes this prospect real: on such platforms, pieces of information (more or less credible) are exchanged in order to build up a “collective opinion”. These pieces of information can be arguments, but people may also vote on arguments put forward by other parties. How can we make sense of this constellation of viewpoints? Is there any well-founded method to aggregate them, to analyze the resulting debates (for instance, so as to single out the best justified ones?). And in a normative perspective, can we conceive and design systems enjoying good properties (that the debate evolved correctly, that the viewpoints were fairly represented, that the outcome reached was satisfying for all the parties, etc.)
This paper addresses the issue of the dynamic enforcement of a constraint in an argumentation system. The system consists in (1) an argumentation framework, made up, notably, of a set of arguments and of an attack relation, (2) an evaluation semantics, and (3) the evaluation result, computed from (1) and (2). An agent may want another agent to consider a new attack, or to have a given argument accepted, or even to relax the definition of the semantics. A constraint on any of the three components is thus defined, and it has to be enforced in the system. The enforcement may result in changes on components of the system. The paper surveys existing approaches for the dynamic enforcement of a constraint and its consequences, and reveals challenging enforcement cases that remain to be investigated.
@article{argAndComp2018,author={Doutre, Sylvie and Mailly, Jean-Guy},title={Constraints and changes: {A} survey of abstract argumentation dynamics},journal={Argument {\&} Computation},volume={9},number={3},pages={223--248},year={2018},url={https://doi.org/10.3233/AAC-180425},doi={10.3233/AAC-180425},}
Argumentation reasoning is a way for agents to evaluate a situation. Given a framework made of conflicting arguments, a semantics allows to evaluate the acceptability of the arguments. It may happen that the semantics associated to the framework has to be changed. In order to perform the most suitable change, the current and a potential new semantics have to be compared. Notions of difference measures between semantics have already been proposed, and application cases where they have to be minimized when a change of semantics has to be performed, have been highlighted. This paper develops these notions, it proposes an additional kind of difference measure, and shows application cases where measures may have to be maximized, and combined.
@inproceedings{eumas2017,title={Comparison Criteria for Argumentation Semantics},booktitle={15th {E}uropean {C}onference on {M}ulti-{A}gent {S}ystems ({EUMAS} 2017)},author={Doutre, Sylvie and Mailly, Jean-Guy},year={2017},}
Change in argumentation frameworks has been widely studied in the recent years. Most of the existing works on this topic are concerned with change of the structure of the argumentation graph (addition or removal of arguments and attacks), or change of the outcome of the framework (acceptance statuses of arguments). Change on the acceptability semantics that is used in the framework has not received much attention so far. Such a change can be motivated by different reasons, especially it is a way to change the outcome of the framework. In this paper, it is shown how semantic change can be used as a way to reach a goal about acceptance statuses in a situation of extension enforcement.
@inproceedings{sum2017,title={Semantic Change and Extension Enforcement in Abstract Argumentation},booktitle={11th {I}nternational {C}onference on {S}calable {U}ncertainty {M}anagement ({SUM} 2017)},author={Doutre, Sylvie and Mailly, Jean-Guy},year={2017},}
Properties of argumentation semantics have been widely studied in the last decades. However, there has been no investigation on the question of difference measures between semantics. Such measures turn helpful when the semantics associated to an argumentation framework may have to be changed, in a way that ensures that the new semantics is not too dissimilar from the old one. Three main notions of difference measures between semantics are defined in this paper. Some of these measures are shown to be distances or semi-distances.
@inproceedings{comma2016,title={Quantifying the Difference between Argumentation Semantics},booktitle={6th {I}nternational {C}onference on {C}omputational {M}odels of {A}rgument ({COMMA} 2016)},author={Doutre, Sylvie and Mailly, Jean-Guy},year={2016},pages={255--262},}
Formalizing dynamics of argumentation has received increasing attention over the last years. While AGM- like representation results for revision of argumentation frameworks (AFs) are now available, similar results for the problem of merging are still missing. In this paper, we close this gap and adapt model-based propositional belief merging to define extension-based merging oper- ators for AFs. We state an axiomatic and a constructive characterization of merging operators through a fam- ily of rationality postulates and a representation theo- rem. Then we exhibit merging operators which satisfy the postulates. In contrast to the case of revision, we observe that obtaining a single framework as result of merging turns out to be a more subtle issue. Finally, we establish links between our new results and previous ap- proaches to merging of AFs, which mainly relied on ax- ioms from Social Choice Theory, but lacked AGM-like representation theorems.
@inproceedings{kr2016,author={Delobelle, J\'er\^ome and Haret, Adrian and Konieczny, S\'ebastien and Mailly, Jean-Guy and Rossit, Julien and Woltran, Stefan},title={Merging of Abstract Argumentation Frameworks},booktitle={15th {I}nternational {C}onference on {P}rinciples of {K}nowledge {R}epresentation and {R}easoning ({KR} 2016)},year={2016},pages={33--42},}
@inproceedings{iaf2016,title={How different are two argumentation semantics?},booktitle={10\`emes {J}ourn\'ees d'{I}ntelligence {A}rtificielle {F}ondamentale ({IAF} 2016)},author={Doutre, Sylvie and Mailly, Jean-Guy},year={2016},}
2015
CoQuiAAS: A Constraint-based Quick Abstract Argumentation Solver
Nowadays, argumentation is a salient keyword in artificial intelligence. The use of argumentation techniques is par- ticularly convenient for thematics such that multiagent systems, where it allows to describe dialog protocols (using persuasion, negotiation, ...) or on-line discussion analysis; it also allows to handle queries where a single agent has to reason with conflicting information (inference in the presence of inconsistency, inconsistency measure). This very rich framework gives numerous reasoning tools, thanks to several acceptability semantics and inference policies. On the other hand, the progress of SAT solvers in the recent years, and more generally the progress on Constraint Programming paradigms, lead to some powerful approaches that permit tackling theoretically hard problems. The needs of efficient applications to solve the usual reasoning tasks in argumentation, together with the capabilities of modern Constraint Programming solvers, lead us to study the encoding of usual acceptability semantics into logical settings. We propose diverse use of Constraint Programming techniques to develop a software library dedicated to argumentative reasoning. We present a library which offers the advantages to be generic and easily adaptable. We finally describe an experimental study of our approach for a set of semantics and inference tasks, and we describe the behaviour of our solver during the First International Competition on Computational Models of Argumentation.
@inproceedings{ictai2015,author={Lagniez, Jean-Marie and Lonca, Emmanuel and Mailly, Jean-Guy},title={{CoQuiAAS}: A {C}onstraint-based {Q}uick {A}bstract {A}rgumentation {S}olver},booktitle={27th {IEEE} {I}nternational {C}onference on {T}ools with {A}rtificial {I}ntelligence ({ICTAI} 2015)},pages={928--935},year={2015},}
Change in abstract argumentation frameworks (AFs) is a very active topic. Especially, the problem of enforcing a set E of arguments, i.e., ensuring that E is an extension (or a subset of an extension) of a given AF F, has received a particular attention in the recent years. In this paper, we define a new family of enforcement operators, for which enforcement can be achieved by adding new arguments (and attacks) to F (as in previous approaches to enforcement), but also by questioning some attacks (and non-attacks) of F. This family includes previous enforcement operators, but also new ones for which the success of the enforcement operation is guaranteed. We show how the enforcement problem for the operators of the family can be modeled as a pseudo-Boolean optimization problem. Intensive experiments show that the method is practical and that it scales up well.
@inproceedings{ijcai2015,title={Extension Enforcement in Abstract Argumentation as an Optimization Problem},booktitle={24th {I}nternational {J}oint {C}onference on {A}rtificial {I}ntelligence ({IJCAI} 2015)},author={Coste-Marquis, Sylvie and Konieczny, S\'ebastien and Mailly, Jean-Guy and Marquis, Pierre},year={2015},pages={2876--2882},}
@inproceedings{iaf2015,title={For\c{c}age d'extension en argumentation abstraite par optimisation bool\'eenne},booktitle={9\`emes {J}ourn\'ees d'{I}ntelligence {A}rtificielle {F}ondamentale ({IAF} 2015)},author={Coste-Marquis, Sylvie and Konieczny, S\'ebastien and Mailly, Jean-Guy and Marquis, Pierre},year={2015},}
CoQuiAAS : Applications de la programmation par contraintes à l’argumentation abstraite
@inproceedings{jfpc2015,title={{CoQuiAAS} : {A}pplications de la programmation par contraintes \`a l'argumentation abstraite},booktitle={11\`emes {J}ourn\'ees {F}rancophones de la {P}rogrammation par {C}ontraintes ({JFPC} 2015)},pages={77--85},author={Lagniez, Jean-Marie and Lonca, Emmanuel and Mailly, Jean-Guy},year={2015},}
This thesis tackles the problem of integrating a new piece of information in an abstract argumenta- tion framework. Such a framework is a directed graph such that its nodes represent the arguments, and the directed edges represent the attacks between arguments. There are different ways to decide which arguments are accepted by the agent who uses such a framework to represent her beliefs. An agent may be confronted with a piece of information such that "this argument should be accepted", which is in contradiction with her current beliefs, represented by her argumentation framework. In this thesis, we have studied several approaches to incorporate a piece of information in an argumenta- tion framework. Our first contribution is an adaptation of the AGM framework for belief revision, which has been de- veloped for characterizing the incorporation of a new piece of information when the agent’s beliefs are represented in a logical setting. We have adapted the rationality postulates from the AGM framework to characterize the revision operators suited to argumentation frameworks, and we have identified several ways to generate the argumentation frameworks resulting from the revision. We have also shown how to use AGM revision as a tool for revising argumentation frameworks. Our approach uses a logical encoding of the argumentation framework to take advantage of the classical re- vision operators, for deriving the expected result. At last, we have studied the problem of enforcing a set of arguments (how to change an argumentation framework so that a given set of arguments becomes an extension). We have developed a new family of operators which guarantee the success of the enforcement process, contrary to the existing approaches, and we have shown that a translation of our approaches into satisfaction and optimization problems makes possible to develop efficient tools for computing the result of the enforcement.
@phdthesis{phdthesis,author={Mailly, Jean-Guy},title={Dynamics of {A}rgumentation {F}rameworks},school={Universit\'e d'Artois},year={2015},}
In this paper, we investigate the revision issue for Dung ar- gumentation frameworks. The main idea is that such frameworks can be translated into propositional formulae, allowing the use of propositional revision operators to perform a rational minimal change. Our translation- based approach to revising argumentation frameworks can take advan- tage of any propositional revision operator ◦. Via a translation, each propositional operator ◦ can be associated with some revision operators ⋆ suited to argumentation frameworks. Some rationality postulates for the ⋆ operators are presented. If the revision formulae are restricted to formulae about acceptance statuses, some ⋆ operators satisfy these pos- tulates provided that the corresponding ◦ operator is AGM.
@inproceedings{jelia2014,title={A Translation-based Approach for Revision of Argumentation Frameworks},booktitle={14th {E}uropean {C}onference on {L}ogics in {A}rtificial {I}ntelligence ({JELIA} 2014)},pages={77--85},author={Coste-Marquis, Sylvie and Konieczny, S\'ebastien and Mailly, Jean-Guy and Marquis, Pierre},year={2014},}
In this paper, we investigate the revision of argumenta- tion systems a‘ la Dung. We focus on revision as mini- mal change of the arguments status. Contrarily to most of the previous works on the topic, the addition of new arguments is not allowed in the revision process, so that the revised system has to be obtained by modify- ing the attack relation only. We introduce a language of revision formulae which is expressive enough for en- abling the representation of complex conditions on the acceptability of arguments in the revised system. We show how AGM belief revision postulates can be trans- lated to the case of argumentation systems. We pro- vide a corresponding representation theorem in terms of minimal change of the arguments statuses. Several distance-based revision operators satisfying the postu- lates are also pointed out, along with some methods to build revised argumentation systems. We also discuss some computational aspects of those methods.
@inproceedings{kr2014,title={On the Revision of Argumentation Systems: Minimal Change of Arguments Statuses},booktitle={14th {I}nternational {C}onference on {P}rinciples of {K}nowledge {R}epresentation and {R}easoning ({KR} 2014)},author={Coste-Marquis, Sylvie and Konieczny, S\'ebastien and Mailly, Jean-Guy and Marquis, Pierre},year={2014},pages={52--61},}
@inproceedings{iaf2014,title={Approche par traduction pour la r\'evision de syst\`emes d'argumentation},booktitle={8\`emes {J}ourn\'ees d'{I}ntelligence {A}rtificielle {F}ondamentale ({IAF} 2014)},pages={77--85},author={Coste-Marquis, Sylvie and Konieczny, S\'ebastien and Mailly, Jean-Guy and Marquis, Pierre},year={2014},}
CoQuiAAS : Applications de la programmation par contraintes à l’argumentation abstraiteIn 11èmes Journées Francophones de la Programmation par Contraintes (JFPC 2015), 2015