AGGREEY was funded by the ANR, and started in Janurary 2023.
Summary: E-democracy is a form of government that allows everybody to participate in the development of laws. It has numerous benefits since it strengthens the integration of citizens in the political debate. Several on-line platforms exist; most of them propose to represent a debate in the form of a graph, which allows humans to better grasp the arguments and their relations. However, once the arguments are entered in the system, little or no automatic treatment is done by such platforms. Given the development of online consultations, it is clear that in the near future we can expect thousands of arguments on some hot topics, which will make the manual analysis difficult and time-consuming. The goal of this project is to use artificial intelligence, computational argumentation theory and natural language processing in order to detect the most important arguments, estimate the acceptability degrees of arguments and predict the decision that will be taken.
Efficient computation of hard reasoning tasks is a key issue in abstract argumentation. One recent approach consists in defining approximate algorithms, i.e. methods that provide an answer that may not always be correct, but outperforms the exact algorithms regarding the computation runtime. One such approach proposes to use the grounded semantics, which is polynomially computable, as a starting point for determining whether arguments are (credulously or skeptically) accepted with respect to various semantics. In this paper, we push further this idea by defining various approaches to evaluate the acceptability of arguments which are not in the grounded extension, neither attacked by it. We have implemented our approaches, and we describe the result of their empirical evaluation.
@inproceedings{ecsqaru2023a,title={Revisiting Approximate Reasoning based on Grounded Semantics},booktitle={Seventeenth {E}uropean {C}onference on {S}ymbolic and {Q}uantitative {A}pproaches to {R}easoning with {U}ncertainty ({ECSQARU} 2023)},author={Delobelle, Jérôme and Mailly, Jean-Guy and Rossit, Julien},year={2023},}
Incomplete Argumentation Frameworks (IAFs) enrich classical abstract argumentation with arguments and attacks whose actual existence is questionable. The usual reasoning approaches rely on the notion of completion, i.e. standard AFs representing "possible worlds" compatible with the uncertain information encoded in the IAF. Recently, extension-based semantics for IAFs that do not rely on the notion of completion have been defined, using instead new versions of conflict-freeness and defense that take into account the (certain or uncertain) nature of arguments and attacks. In this paper, we give new insights on this reasoning approach, by adapting the well-known grounded semantics to this framework in two different versions. After determining the computational complexity of our new semantics, we provide a principle-based analysis of these semantics, as well as the ones previously defined in the literature, namely the complete, preferred and stable semantics.
@inproceedings{ecsqaru2023b,title={Extension-based Semantics for Incomplete Argumentation Frameworks: Grounded Semantics and Principles},booktitle={Seventeenth {E}uropean {C}onference on {S}ymbolic and {Q}uantitative {A}pproaches to {R}easoning with {U}ncertainty ({ECSQARU} 2023)},author={Mailly, Jean-Guy},year={2023},}
We study the notion of realization of extensions in abstract argumentation. It consists in reversing the usual reasoning process: instead of computing the extensions of an argumentation framework, we want to determine whether a given set of extensions corresponds to some (set of) argumentation framework(s) (AFs); and more importantly we want to identify such an AF (or set of AFs) that realizes the set of extensions. While deep theoretical studies have been concerned with realizability of extensions sets, there are few computational approaches for solving this problem. In this paper, we generalize the concept of realizability by introducing two parameters: the number k of auxiliary arguments (i.e. those that do not appear in any extension), and the number m of AFs in the result. We define a translation of k-m-realizability into Quantified Boolean Formulas (QBFs) solving. We also show that our method allows to guarantee that the result of the realization is as close as possible to some input AF. Our method can be applied in the context of AF revision operators, where revised extensions must be mapped to a set of AFs while ensuring some notion of proximity with the initial AF.
@inproceedings{clar2023,title={A Logical Encoding for k-m-Realization of Extensions in Abstract Argumentation},booktitle={Fifth {I}nternational {C}onference on {L}ogic and {A}rgumentation ({CLAR} 2023)},author={Mailly, Jean-Guy},year={2023},}
Graph generators are a powerful tool to provide benchmarks for various sub elds of KR (e.g. abstract argumentation, description logics, etc.) as well as other domains of AI (e.g. resources allocation, gossip problem, etc.). In this paper, we describe a new approach for generating graphs based on the idea of communities, i.e. parts of the graph which are densely connected, but with fewer connections between di erent communities. We discuss the design of an application named crusti_g2io implementing this idea, and then focus on a use case related to abstract argumentation. We show how crusti_g2io can be used to generate structured hard argumentation instances which are challenging for the fourth International Competition on Computational Models of Argumentation (ICCMA’21) solvers.
@inproceedings{argapp2023a,title={A New Evolutive Generator for Graphs with Communities and its Application to Abstract Argumentation},booktitle={First {I}nternational {W}orkshop on {A}rgumentation and {A}pplications ({Arg\&App} 2023)},author={Lagniez, Jean-Marie and Lonca, Emmanuel and Mailly, Jean-Guy and Rossit, Julien},year={2023},series={{CEUR} Workshop Proceedings},volume={3472},pages={52--64},}
In this paper, we discuss the application of abstract argumentation mechanisms to resources allocation. We show how such problems can be modeled as abstract argumentation frameworks, such that specific sets of arguments corresponds to interesting solutions of the problem. By interesting solutions, here we mean Local Envy-Free (LEF) allocations. Envy-freeness is an important notion of fairness in resources allocation, assuming than no agent should prefer the resource allocated to another agent. We focus on LEF, a generalized form of envy-freeness, and we show that LEF allocations corresponds to some specific sets of arguments in our argument-based modeling of the problem. This work in progress paves the way to richer connections between the various models of argumentation and resources allocation problems.
@inproceedings{argapp2023b,title={Abstract Argumentation Applied to Fair Resources Allocation: A Preliminary Study},booktitle={First {I}nternational {W}orkshop on {A}rgumentation and {A}pplications ({Arg\&App} 2023)},author={Mailly, Jean-Guy},year={2023},series={{CEUR} Workshop Proceedings},volume={3472},pages={85--91},}
@inproceedings{iaf2023a,title={A New Evolutive Generator for Graphs with Communities and its Application to Abstract Argumentation},booktitle={17\`emes {J}ourn\'ees d'{I}ntelligence {A}rtificielle {F}ondamentale ({IAF} 2023)},author={Lagniez, Jean-Marie and Lonca, Emmanuel and Mailly, Jean-Guy and Rossit, Julien},year={2023},}
@inproceedings{iaf2023b,title={Similarity Measures between Order-Sorted Logical Arguments},booktitle={17\`emes {J}ourn\'ees d'{I}ntelligence {A}rtificielle {F}ondamentale ({IAF} 2023)},author={David, Victor and Delobelle, Jérôme and Mailly, Jean-Guy},year={2023},}