Defeasible Logic is Stable

摘要

We define, and give some of the intuition behind the definition of, a nonmonotonic logic called defeasible logic. Results are proved which enable us to see how well the definition captures our intuitions. These results indicate that defeasible logic is well behaved. Section 3 considers, among other things, what happens when a defeasible logic is inconsistent. The next two sections are concerned with stability, that is, the property of being undisturbed by the addition or deletion of redundant information. In Section 4 we consider redundant rules, and in Section 5 we consider lemma addition. That is the adding of a proved result to the‘axioms’of the lo