Extending DeLP with Attack and Support for Defeasible Rules

ANDREA COHEN; ALEJANDRO J. GARCÍA; GUILLERMO R. SIMARI

Conferencia; 12th Ibero-American Conference on Artificial Intelligence; 2010

In several formalisms of classical argumentation two kinds of defeaters are considered: rebutting and undercutting. The former represents an attack to a conclusion and the latter an attack to an inference step. Defeasible Logic Programming (DeLP) is a formalism that combines argumentation and logic programming and provides a concrete argumentation system where arguments are built using program rules and facts. DeLP allows to identify arguments whose conclusions or intermediate conclusions are in contradiction. In that way, rebutting defeaters are captured. Nevertheless, in DeLP is not possible to represent an explicit attack to a program rule in order to capture undercutting defeaters. The contribution of this work is to extend the formalism of DeLP in order to allow the representation of both support and attack for defeasible rules. Therefore, it will be possible to build arguments that provide reasons for or against a defeasible rule and thus, undercutting defeaters and backings could be constructed.