Modeling Defeasibility in an Extended Logic Programming Setting Using an Abstract Argumentation Framework

Defeasible argumentation has become a well-known approach to model commonsense reasoning. This has motivated the development of several alternative argumentative frameworks. The MTDR argumentative framework [SL92, SCG94] has proven to be a powerful approach to formalize defeasible argumentation, particularly in a logic-programming setting called defeasible logic programming (DLP) [Gar97]. Independently, the abstract argumentation framework developed by Bondarenko et al: [BDKT97] provides a sound theoretical basis for considering di®erent kinds of non-monotonic reasoning systems. In recent work [KT99], the main focus has been on capturing semantics of logic programming in argumentative terms. This paper discusses a uniform way of conceptualizing defeasible rules and strict rules (used in defeasible logic programming) using extended logic programming under an abstract argumentation framework. As a result, we get an alternative formalization of DLP which allows a natural comparison of the well-founded semantics of normal programs (de ̄ned in argumentative terms) and the procedural semantics associated with defeasible logic programs.