Modeling defeasible reasoning with multiple agents

The authors present a generalized proof theory for defeasible reasoning and briefly explain the relationship of this system to other nonmonotonic formalisms. Then they present a proof theory and semantics for a logic that makes it possible to explicitly model internal perspectives or multiple agents. This ordered logic properly extends defeasible logic by allowing more complex precedence structure on rules. It provides a mechanism for resolving conflicts between competing perspectives without obscuring the opinions of those perspectives. It is shown how a defeasible theory can be transformed into an equivalent theory in the new logic for multiagent reasoning. Finally, the authors consider some examples and discuss how it is possible to specify the relative superiority of some experts over others in a natural way using ordered logic