Argumentation Semantics for Defeasible Logic

Defeasible reasoning is a simple but efficient rule-based approach to nonmonotonic reasoning. It haspowerful implementations and shows promise to be applied in the areas of legal reasoning and themodeling of business rules. This paper establishes significant links between defeasible reasoning andargumentation. In particular, Dung-like argumentation semantics is provided for two key defeasiblelogics, of which one is ambiguity propagating and the other ambiguity blocking.There are several reasons for the significance of this work: (a) establishing links between formalsystems leads to a better understanding and cross-fertilization, in particular our work sheds light on theargumentation-theoretic features of defeasible logic; (b) we provide the first ambiguity blocking Dung-like argumentation system; (c) defeasible reasoning may provide an efficient implementation platformfor systems of argumentation; and (d) argumentation-based semantics support a deeper understandingof defeasible reasoning, especially in the context of the intended applications.