Argument & Computation - Volume 15, issue 3

Authors: Odekerken, Daphne | Borg, AnneMarie | Bex, Floris

Article Type: Research Article

Abstract: We explore the computational complexity of justification, stability and relevance in incomplete argumentation frameworks (IAFs). IAFs are abstract argumentation frameworks that encode qualitative uncertainty by distinguishing between certain and uncertain arguments and attacks. These IAFs can be completed by deciding for each uncertain argument or attack whether it is present or absent. Such a completion is an abstract argumentation framework, for which it can be decided which arguments are acceptable under a given semantics. The justification status of an argument in a completion then expresses whether the argument is accepted (in ), not accepted because it is attacked by …an accepted argument (out ) or neither (undec ). For a given IAF and certain argument, the justification status of that argument need not be the same in all completions. This is the issue of stability , where an argument is stable if its justification status is the same in all completions. For arguments that are not stable in an IAF, the relevance problem is of interest: which uncertain arguments or attacks should be investigated for the argument to become stable? In this paper, we define justification, stability and relevance for IAFs and provide a complexity analysis for these problems under grounded, complete, preferred and stable semantics. Show more

Keywords: Incomplete argumentation frameworks, stability, relevance, complexity

DOI: 10.3233/AAC-230002

Citation: Argument & Computation, vol. 15, no. 3, pp. 251-308, 2024

Authors: Wakaki, Toshiko

Article Type: Research Article

Abstract: The motivation of this study is that Reiter’s default theory as well as assumption-based argumentation frameworks corresponding to default theories have difficulties in handling disjunctive information, while a disjunctive default theory (ddt ) avoids them. This paper presents the semantic correspondence between generalized assumption-based argumentation (ABA) and extended disjunctive logic programming as well as the correspondence between ABA and nonmonotonic reasoning approaches such as disjunctive default logic and prioritized circumscription. To overcome the above-mentioned difficulties of ABA frameworks corresponding to default theories, we propose an assumption-based framework (ABF) translated from an extended disjunctive logic program (EDLP) since an EDLP can …be translated into a ddt . Our ABF incorporates explicit negation and the connective of disjunction “|” to Heyninck and Arieli’s ABF induced by a disjunctive logic program. In this paper, first, we show how arguments are constructed from disjunctive rules in our proposed ABF. Then, we show the correspondence between answer sets of an EDLP P and stable extensions of the ABF translated from P with trivialization rules. After defining rationality postulates, we show answer sets of a consistent EDLP are captured by consistent stable extensions of the translated ABF with no trivialization rules. Finally, we show the correspondence between ABA and disjunctive default logic (resp. prioritized circumscription). The relation between ABA and possible model semantics of EDLPs is also discussed. Show more

Keywords: Assumption-based argumentation, extended disjunctive logic programs, disjunctive default logic, arguments, prioritized circumscription

DOI: 10.3233/AAC-220019

Citation: Argument & Computation, vol. 15, no. 3, pp. 309-353, 2024

Authors: Shaheen, Qurat-ul-ain | Budzynska, Katarzyna | Sierra, Carles

Article Type: Research Article

Abstract: This work presents a requirement analysis for collaborative dialogues among medical experts and an inquiry dialogue game based on this analysis for incorporating explainability into multiagent system design. The game allows experts with different knowledge bases to collaboratively make recommendations while generating rich traces of the reasoning process through combining explanation-based illocutionary forces in an inquiry dialogue. The dialogue game was implemented as a prototype web-application and evaluated against the specification through a formative user study. The user study confirms that the dialogue game meets the needs for collaboration among medical experts. It also provides insights on the real-life value …of dialogue-based communication tools for the medical community. Show more

Keywords: Inquiry dialogue game, collaborative decisions, expert decisions, explainable artificial intelligence, human-centred computing

DOI: 10.3233/AAC-230010

Citation: Argument & Computation, vol. 15, no. 3, pp. 355-390, 2024