Defeasible logic graphs for decision support

Abstract

Knowledge based systems provide decision support by applying a previously developed representation of knowledge for a particular domain. We describe a method for representing knowledge about any domain using defeasible logic graphs. Because these graphs are based on a defeasible logic of the sort described in (Nute, 1992), they can represent uncertain or incomplete knowledge. We reason about the represented domain by propagating markers in the graph to show which propositions are true, false, or unestablished. We propose to construct an argumentation based software system incorporating defeasible logic graphs. We establish the formal foundations for such a system by showing that the inference mechanism for defeasible logic graphs is sound and complete with respect to defeasible logic.