Weiwei Chen

Selected Publications

1. JLC

   Guaranteeing Admissibility of Abstract Argumentation Frameworks with Rationality and Feasibility Constraints

   Chen, Weiwei

   Journal of Logic and Computation 2021

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   This paper considers the problem of under what circumstances an aggregation rule guarantees admissible sets of arguments that represent a good compromise between several extensions, i.e., sets of arguments of abstract argumentation frameworks each provided by a different individual. We start by showing that the preservation results of Dung’s admissibility, graded admissibility and strong admissibility during the aggregation of extensions are negative. To overcome such negative results, we define a model for extension aggregation that clearly separates the constraint supposed to be satisfied by individuals and the constraint that must be met by the collective decision. Using this model, we show that the majority rule guarantees admissible sets on profiles that satisfy a variant of Dung’s admissibility, as well as profiles of extensions with some specific characteristics.

2. AIJ

   Preservation of Semantic Properties in Collective Argumentation: The Case of Aggregating Abstract Argumentation Frameworks

   Chen, Weiwei, and Endriss, Ulle

   Artificial Intelligence 2019

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   An abstract argumentation framework can be used to model the argumentative stance of an agent at a high level of abstraction, by indicating for every pair of arguments that is being considered in a debate whether the first attacks the second. When modelling a group of agents engaged in such a debate, we may wish to aggregate their individual argumentation frameworks to obtain a single such framework that reflects the consensus of the group. While agents typically will not agree on every single attack, there may well be high-level agreement on semantic properties, such as whether a given argument should be accepted or whether there are any acceptable arguments at all. Using techniques from social choice theory, we analyse the circumstances under which such semantic properties agreed upon by the individual agents will be preserved under aggregation. Our results cover semantic properties formulated in terms of six of the most widely used extension-based semantics for abstract argumentation and range from positive results that show that certain aggregation rules can provide the desired preservation guarantees to impossibility theorems that show that certain combinations of requirements cannot be met by any reasonable aggregation rule.

3. COMMA

   Aggregating Alternative Extensions of Abstract Argumentation Frameworks: Preservation Results for Quota Rules

   Chen, Weiwei, and Endriss, Ulle

   In Proceedings of the 7th International Conference on Computational Models of Argument (COMMA) 2018

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   When confronted with the same abstract argumentation framework, specifying a set of arguments and an attack-relation between them, different agents may disagree on which arguments to accept, i.e., they may choose different extensions. In the context of designing systems to support collective argumentation, we may then wish to aggregate such alternative extensions into a single extension that appropriately reflects the views of the group as a whole. Focusing on a conceptually and computationally simple family of aggregation rules, the quota rules, we analyse under what circumstances relevant properties of extensions shared by all extensions reported by the individual agents will be preserved under aggregation. The properties we consider are the classical properties of argumentation semantics, such as being a conflict-free, a complete, or a preferred extension. We show that, while for some properties there are quota rules that guarantee their preservation, for the more demanding properties it is impossible to do so in general.