Title Abstract Contents 1 2 3 4 5 Acknowlegments References Footnotes

1 Introduction

Dialectical argumentation has two main characteristics (cf. for instance Rescher, 1977):

1. The arguments used to support a conclusion can be challenged by counterarguments.
2. Whether an argument justifies a conclusion depends on the stage of the argumentation process.

These characteristics have recently lead to renewed attention of the artificial intelligence community (cf. Bench-Capon, 1995; Loui, 1995), for two reasons: First, the notion of counterargument sheds new light on nonmonotonic reasoning, and second, the process character of argumentation directly inspires new computational techniques.

In a recent paper, Dung (1995) has thoroughly investigated the relations of (unstructured [1]) arguments and counterarguments in terms of admissible sets. In this paper, a model of the stages of the argumentation process is discussed, related to the model of Verheij (1995a, 1995b), and compared to Dung's approach.

In section 2, the main definitions of the two approaches are discussed. In section 3, we discuss their (close) formal connections. In section 4, we give some examples by means of argumentation diagrams. Section 5 summarizes the conclusions of the paper.

Title Abstract Contents 1 2 3 4 5 Acknowlegments References Footnotes