In this paper, we argue for four points that are refinements of how arguments and defeat have been used in argument-based nonmonotonic reasoning. First we argue that an argument can be defeated because it contains a weak sequence of steps; second that arguments accrue, which means that arguments for a conclusion reinforce each other; third that defeat can be compound, which means that groups of arguments can defeat other groups of arguments; fourth that defeated arguments must be distinguished from not yet considered arguments. In related work these points are overlooked, or even denied. We describe a formalism that incorporates them.
Keywords: nonmonotonic reasoning, defeasible argumentation
Verheij, Bart (1995). Arguments and defeat in argument-based nonmonotonic reasoning. Progress in Artificial Intelligence. 7th Portuguese Conference on Artificial Intelligence (EPIA '95; Lecture Notes in Artificial Intelligence 990) (eds. Carlos Pinto-Ferreira and Nuno J. Mamede), pp. 213-224. Springer, Berlin. Also published as report SKBS/B3.A/95-04.
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