Work

Complexity Results and Algorithms for Preferential Argumentative Reasoning in ASPIC+

Year: 2024

Type: conference-paper

Abstract: We provide complexity results and algorithms for reasoning in the central structured argumentation formalism of ASPIC+. Considering ASPIC+ accommodated with preferences under the last-link principle, the results are made possible by rephrasing several argumentation semantics---admissible, complete, stable, preferred and grounded---in terms of defeasible elements of an ASPIC+ theory for both democratic and elitist last-link lifting. Via the rephrasing, we establish that acceptance is polynomial-time computable under grounded semantics, and complete for either NP, coNP, or Pi_P^2, depending on the reasoning mode and semantics. We also detail answer set programming encodings for deciding acceptance for the NP/coNP-complete reasoning tasks, and empirically show that it scales significantly better than first translating ASPIC+ reasoning tasks to abstract argumentation. Finally, we show that, in contrast to the last-link principle, it is NP-hard to compute the grounded extension under the weakest-link principle.

DOI: 10.24963/kr.2024/49

Authors: Tuomo Lehtonen, Daphne Odekerken, Johannes P. Wallner, Matti Järvisalo

Institutions: Aalto University, Utrecht University, Korps Landelijke Politiediensten, Graz University of Technology, University of Helsinki

Language: English

Topic: Multi-Agent Systems and Negotiation

Subfield: Artificial Intelligence

Field: Computer Science

Domain: Physical Sciences

Open Access status: gold

Funder: Austrian Science Fund

Award: A Novel Computational Workflow for Argumentation in AI

OpenAlex ID: W4403792853