We give some design guidelines for argumentation systems. These guidelines are meant to indicate essential features of argumentation when used to support “practical reasoning”. We express the guidelines in terms of postulates. We use a notion of redundancy to provide a formal counterpart of these postulates. We study the satisfaction of these postulates in two existing argumentation frameworks:...

In this paper we introduce a logic of abstract argumentation capturing Dung’s theory of abstract argumentation, based on connectives for attack and defend. We extend it to a modal logic of abstract argumentation to generalize Dung’s theory and define variants of it. Moreover, we use the logic to relate Dung’s theory of abstract argumentation to more traditional conditional and comparative forma...

Extension-based argumentation semantics have shown to be a suitable approach for performing practical reasoning. An important concern in extensionbased-argumentation semantics is the computational complexity of the decision problems that has been shown to range from NP-complete to Π 2 -complete. In this paper, we introduce a generic extension-based argumentation semantics solver, that is called...

In this paper, we show that preferences intervene twice in argumentation frameworks: i) to compute standard solutions (i.e. extensions), and ii) to refine those solutions (i.e. to return only the preferred extensions). The two roles are independent and obey to distinct postulates. After introducing and studying the postulates, we provide an example of a formal framework which models the two rol...

In this paper, we model a recent legal case as presented in a court of first instance using argument schemes and an argumentation framework, providing a formal analysis of the case and how the outcome was determined. The paper contributes to the body of literature that formally analyses legal cases in terms of arguments and argument schemes. It is novel in that we analyse a case in a court of f...

Argumentation Frameworks

Argumentation is a process of evaluating and comparing a set of arguments. A way to compare them consists in using a ranking-based semantics which rank-order arguments from the most to the least acceptable ones. Recently, a number of such semantics have been proposed independently, often associated with some desirable properties. However, there is no comparative study which takes a broader pers...

The aim of the paper is to propose a robust model of interpersonal argumentation (IP). The IP-arguments directly address participants of communication, i.e. they refer to speech acts rather than to propositional contents. Argumentation theory recognizes several IP-arguments, e.g. argument from position to know or ad hominem arguments. The model proposed in the paper enables to describe referenc...

Argumentation is a process of evaluating and comparing a set of arguments. A way to compare them consists in using a ranking-based semantics which rank-order arguments from the most to the least acceptable ones. Recently, a number of such semantics have been proposed independently, often associated with some desirable properties. However, there is no comparative study which takes a broader pers...

We present a generalization of Dung’s theory of argumentation enabling to take account for some additional constraints on the admissible sets of arguments, expressed as a propositional formula over the set of arguments. We point out several semantics for such constrained argumentation frameworks, and compare the corresponding inference relations w.r.t. cautiousness. We show that our setting enc...