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Comparing Two Unique Extension Semantics for Formal Argumentation: Ideal and Eager
"... In formal argumentation, grounded semantics is well known for yielding exactly one unique extension. Since grounded semantics has a very sceptical nature, one can ask the question whether it is possible to define a unique extension semantics that is more credulous. Recent work of Dung, Mancarella an ..."
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Cited by 17 (4 self)
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In formal argumentation, grounded semantics is well known for yielding exactly one unique extension. Since grounded semantics has a very sceptical nature, one can ask the question whether it is possible to define a unique extension semantics that is more credulous. Recent work of Dung, Mancarella and Toni proposes what they call ideal semantics, which is a unique extension semantics that is more credulous than grounded semantics. In the current paper, we define a unique extension semantics called eager semantics that is even more credulous than ideal semantics. We then examine how this semantics relates to the existing argumentation semantics proposed by Dung and others.
Complete Extensions in Argumentation Coincide with ThreeValued Stable Models in Logic Programming
, 2009
"... In this paper, we prove the correspondence between complete extensions in abstract argumentation and 3valued stable models in logic programming. This result is in line with earlier work of [8] that identified the correspondence between the grounded extension in abstract argumentation and the wellf ..."
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In this paper, we prove the correspondence between complete extensions in abstract argumentation and 3valued stable models in logic programming. This result is in line with earlier work of [8] that identified the correspondence between the grounded extension in abstract argumentation and the wellfounded model in logic programming, as well as between the stable extensions in abstract argumentation and the stable models in logic programming. We believe the results of this paper are not only relevant by themselves, but can also potentially be used for future work on the correspondence between argumentation and logic programming semantics.
Dynamics in argumentation with single extensions: Abstraction principles and the grounded extension
 Proceedings of the 10th European Conference on Symbolic and Quantitative Approaches to Reasoning with Uncertainty (ECSQARU 2009), volume 5590 of Lecture Notes in Computer Science
"... Abstract. In this paper we consider the dynamics of abstract argumentation in Baroni and Giacomin’s framework for the evaluation of extension based argumentation semantics. Following Baroni and Giacomin, we do not consider individual approaches, but we define general principles or postulates that in ..."
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Abstract. In this paper we consider the dynamics of abstract argumentation in Baroni and Giacomin’s framework for the evaluation of extension based argumentation semantics. Following Baroni and Giacomin, we do not consider individual approaches, but we define general principles or postulates that individual approaches may satisfy. In particular, we define abstraction principles for the attack relation, and for the arguments in the framework. We illustrate the principles on the grounded extension. In this paper we consider only principles for the single extension case, and leave the multiple extension case to further research. 1
Collective Argument Evaluation as Judgement Aggregation
 In 9th International Joint Conference on Autonomous Agents & Multi Agent Systems, AAMAS’2010
, 2010
"... A conflicting knowledge base can be seen abstractly as a set of arguments and a binary relation characterising conflict among them. There may be multiple plausible ways to evaluate conflicting arguments. In this paper, we ask: given a set of agents, each with a legitimate subjective evaluation of a ..."
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A conflicting knowledge base can be seen abstractly as a set of arguments and a binary relation characterising conflict among them. There may be multiple plausible ways to evaluate conflicting arguments. In this paper, we ask: given a set of agents, each with a legitimate subjective evaluation of a set of arguments, how can they reach a collective evaluation of those arguments? After formally defining this problem, we extensively analyse an argumentwise plurality voting rule, showing that it suffers a fundamental limitation. Then we demonstrate, through a general impossibility result, that this limitation is more fundamentally rooted. Finally, we show how this impossibility result can be circumvented by additional domain restrictions.
Dynamics in Argumentation with Single Extensions: Attack Refinement and the Grounded Extension (Extended Abstract)
"... We introduce nine attack refinement principles stating whether the extension stays the same if we add a single attack, and we show that the grounded extension satisfies five of them. We define also an extension called acyclic attack refinement by adding a loop condition, and we show that the grounde ..."
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Cited by 12 (2 self)
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We introduce nine attack refinement principles stating whether the extension stays the same if we add a single attack, and we show that the grounded extension satisfies five of them. We define also an extension called acyclic attack refinement by adding a loop condition, and we show that the grounded extension satisfies one of the acyclic attack refinement principles. Moreover, we define an extension called conditional attack refinement taking alternative attackers into account, and we give an example of a conditional attack refinement principle satisfied by the grounded extension.
On the logic of argumentation theory
, 2010
"... The paper applies modal logic to formalize fragments of argumentation theory. Such formalization allows to import, for free, a wealth of new notions (e.g., argument equivalence), new techniques (e.g., calculi, modelchecking games, bisimulation games), and results (e.g., completeness of calculi, ade ..."
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Cited by 12 (4 self)
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The paper applies modal logic to formalize fragments of argumentation theory. Such formalization allows to import, for free, a wealth of new notions (e.g., argument equivalence), new techniques (e.g., calculi, modelchecking games, bisimulation games), and results (e.g., completeness of calculi, adequacy of games, complexity of modelchecking) from logic to argumentation.
K.: Pareto optimality in abstract argumentation
 In Proc. of AAAI 2008
"... Since its introduction in the midnineties, Dung’s theory of abstract argumentation frameworks has been influential in artificial intelligence. Dung viewed arguments as abstract entities with a binary defeat relation among them. This enabled extensive analysis of different (semantic) argument accept ..."
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Cited by 10 (1 self)
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Since its introduction in the midnineties, Dung’s theory of abstract argumentation frameworks has been influential in artificial intelligence. Dung viewed arguments as abstract entities with a binary defeat relation among them. This enabled extensive analysis of different (semantic) argument acceptance criteria. However, little attention was given to comparing such criteria in relation to the preferences of selfinterested agents who may have conflicting preferences over the final status of arguments. In this paper, we define a number of agent preference relations over argumentation outcomes. We then analyse different argument evaluation rules taking into account the preferences of individual agents. Our framework and results inform the mediator (e.g. judge) to decide which argument evaluation rule (i.e. semantics) to use given the type of agent population involved.
On the revision of argumentation systems: Minimal change of arguments status
 In Proc. TAFA
"... In this paper, we investigate the revision of argumentation systems a ̀ la Dung. We focus on revision as minimal change of the arguments status. Contrarily to most of the previous works on the topic, the addition of new arguments is not allowed in the revision process, so that the revised system h ..."
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Cited by 8 (0 self)
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In this paper, we investigate the revision of argumentation systems a ̀ la Dung. We focus on revision as minimal change of the arguments status. Contrarily to most of the previous works on the topic, the addition of new arguments is not allowed in the revision process, so that the revised system has to be obtained by modifying the attack relation only. We introduce a language of revision formulae which is expressive enough for enabling the representation of complex conditions on the acceptability of arguments in the revised system. We show how AGM belief revision postulates can be translated to the case of argumentation systems. We provide a corresponding representation theorem in terms of minimal change of the arguments statuses. Several distancebased revision operators satisfying the postulates are also pointed out, along with some methods to build revised argumentation systems. We also discuss some computational aspects of those methods.
Splitting argumentation frameworks: An empirical evaluation
 In TAFA
, 2011
"... Abstract. In a recent paper Baumann [1] has shown that splitting results, similar to those known for logic programs under answer set semantics and default logic, can also be obtained for Dung argumentation frameworks (AFs). Under certain conditions a given AF A can be split into subparts A1 and A2 ..."
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Abstract. In a recent paper Baumann [1] has shown that splitting results, similar to those known for logic programs under answer set semantics and default logic, can also be obtained for Dung argumentation frameworks (AFs). Under certain conditions a given AF A can be split into subparts A1 and A2 such that extensions of A can be computed by (1) computing an extension E1 of A1, (2) modifying A2 based on E1, and (3) combining E1 and an extension E2 of the modified variant of A2. In this paper we perform a systematic empirical evaluation of the effects of splitting on the computation of extensions. Our study shows that the performance of algorithms may drastically improve when splitting is applied. 1
An Argument Game for Stable Semantics
, 2008
"... In this paper, we present a discussion game for argumentation under stable semantics. Our work is inspired by Vreeswijk and Prakken, who have defined a similar game for preferred semantics. In the current paper, we restate Vreeswijk and Prakken’s work using the approach of argument labellings and th ..."
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Cited by 6 (5 self)
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In this paper, we present a discussion game for argumentation under stable semantics. Our work is inspired by Vreeswijk and Prakken, who have defined a similar game for preferred semantics. In the current paper, we restate Vreeswijk and Prakken’s work using the approach of argument labellings and then show how it can be adjusted for stable semantics. The nature of the resulting argument game is somewhat unusual, since stable semantics does not satisfy the property of relevance.