A practical system for defeasible reasoning and belief revision
We presented a computational system capable of defeasible reasoning, of revising its beliefs, and which uses truth maintenance techniques to maintain its set of beliefs.
An important point of our work is the fact that the nonmonotonic logic, the BR theory, and the BR system were not developed independently, but rather in an unified way. Thus, the logic itself determines the dependencies between propositions, which are essential to BR systems; the BR theory considers SWMC as the underlying logic, and is thus appropriate to guide the changes in the beliefs of a system whose reasoning is based on this logic; the system's reasoning is guided by SWMC, and its updates are based on the BR theory.
Although the underlying formalisms, i.e., the logic and the BR theory, were developed without any particular application in mind, we came to the conclusion that the resulting system can be successfully used in the solution on typical problems of AI, namely in the areas of diagnosis, inheritance, and counterfactual reasoning. This success comes from the combined use of the two formalisms as well as the truth maintenance techniques.
KeywordsPartial Order Belief Revision Default Rule Underlying Logic Nonmonotonic Logic
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