Decembre 12, 2017, 2:30pm, salle des thèses de la faculté Jean Perrin


Dung’s theory of abstract argumentation is a formalism that represents conflicting information using an argumentation framework. Extension-based semantics have been introduced to determine, given an argumentation framework, the justifiable points of view on the acceptability of the arguments. However, these semantics are not appropriate for some applications. So alternative semantics, called ranking-based semantics, have recently been evolved. Such semantics produces, for a given argumentation framework, a ranking on its arguments from the most acceptable to the least one(s). The overall aim of this thesis is to propose and study ranking-based semantics in the context of abstract argumentation.

We first define a new family of ranking-based semantics based on a propagation principle which allow us to control the influence of non-attacked arguments on the acceptability of arguments. We investigate the properties of these semantics, the relationships between them but also with other existing semantics.

Then, we provide a thorough analysis of ranking-based semantics in two different ways. The first one is an empirical comparison on randomly generated argumentation frameworks which reveals insights into similarities and differences between ranking-based semantics. The second one is an axiomatic comparison of all these semantics with respect to the proposed properties aiming to better understand the behavior of each semantics.

At last, we question the ability of the existing ranking-based semantics to capture persuasion settings and introduce a new parametrized ranking-based semantics which is more appropriate in this context.


  • Leila AMGOUD - Directeur de recherche CNRS, IRIT - Université Paul Sabatier (Rapporteur)
  • Gerhard BREWKA - Professeur, University of Leipzig (Rapporteur)
  • Matthias THIMM - Maître de conférence (HDR), University of Koblenz-Landau (Rapporteur)
  • Anthony HUNTER - Professeur, University College London (Examinateur)
  • Pierre MARQUIS - Professeur, CRIL - Université d’Artois (Examinateur)
  • Elise BONZON - Maître de conférence, LIPADE - Université Paris Descartes (Encadrante)
  • Sébastien KONIECZNY - Directeur de recherche CNRS, CRIL - Université d’Artois (Directeur)
  • Nicolas MAUDET - Professeur, LIP6 - Université Pierre et Marie Curie (Directeur)