Diversity of Extensions in Abstract Argumentation

Fichte, Johannes K.; Hecher, Markus; Mahmood, Yasir; Wang, Zhengjun

doi:10.24963/ijcai.2026/428

Diversity of Extensions in Abstract Argumentation

Johannes K. Fichte, Markus Hecher, Yasir Mahmood, Zhengjun Wang

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Proceedings of the Thirty-Fifth International Joint Conference on Artificial Intelligence. Main Track. Pages 3846-3854.

https://doi.org/10.24963/ijcai.2026/428

Keywords

Knowledge Representation and Reasoning: Argumentation
Knowledge Representation and Reasoning: Computational complexity of reasoning

Abstract

Argumentation is an important topic of AI for modeling and reasoning about arguments. In abstract argumentation, we consider directed graphs, so-called argumentation frameworks (AF), that express conflicts between arguments. The semantics is defined

by the notion of extensions, which are sets of arguments that satisfy particular relationship conditions in the AF. Usually, standard reasoning in argumentation do not reveal how far apart extensions are.

We introduce a quantitative notion of diversity of extensions based on the symmetric-difference and provide a systematic complexity classification. Intuitively, diversity captures whether extensions of a framework (accepted viewpoints) differ only marginally or represent fundamentally incompatible sets of arguments. We study whether an AF admits k-diverse extensions, admits k-diverse extensions covering specific arguments, and to compute the largest k for which an AF admits k-diverse extensions. We outline a prototype and provide an evaluation for computing diversity levels.

Johannes K. Fichte, Markus Hecher, Yasir Mahmood, and Zhengjun Wang. 2026. Diversity of Extensions in Abstract Argumentation. In Proceedings of the Thirty-Fifth International Joint Conference on Artificial Intelligence, IJCAI-26. IJCAI, 3846–3854. https://doi.org/10.24963/ijcai.2026/428

@inproceedings{ijcai2026p428,
  title     = {Diversity of Extensions in Abstract Argumentation},
  author    = {Fichte, Johannes K. and Hecher, Markus and Mahmood, Yasir and Wang, Zhengjun},
  booktitle = {Proceedings of the Thirty-Fifth International Joint Conference on
               Artificial Intelligence, {IJCAI-26}},
  publisher = {International Joint Conferences on Artificial Intelligence Organization},
  editor    = {Diego Calvanese},
  pages     = {3846--3854},
  year      = {2026},
  month     = {8},
  note      = {Main Track},
  doi       = {10.24963/ijcai.2026/428},
  url       = {https://doi.org/10.24963/ijcai.2026/428},
}

TY  - CPAPER
TI  - Diversity of Extensions in Abstract Argumentation
AU  - Fichte, Johannes K.
AU  - Hecher, Markus
AU  - Mahmood, Yasir
AU  - Wang, Zhengjun
T2  - Proceedings of the Thirty-Fifth International Joint Conference on Artificial Intelligence, IJCAI-26
PB  - International Joint Conferences on Artificial Intelligence Organization
PY  - 2026
SP  - 3846
EP  - 3854
DO  - 10.24963/ijcai.2026/428
UR  - https://doi.org/10.24963/ijcai.2026/428
ER  -