可能性缺省逻辑及其应用

本文分析了Yager用可能性理论框架来表示缺省知识的形式化方法，并测试了三类不同的应用方案，得到的结果与Reiter的缺省逻辑得到的结果相比较，表明只在具有严格的约束的缺省逻辑下，Yager的形式化方法才与Reiter的缺省逻辑具有一定的相关性，我们指出了它们在一般缺省理论下的不匹配处，并给出了以不动点机制抽改进方来消除这
些不匹配。

Possibility Theory-Based Default Logic and Its Application

This paper analyzes the formalism proposed by Yager to represent default knowledge in the framework of possibility theory.Three different application schemes are examined.The results produced by these application schemes are compared with those by Reiter's default logic.It is shown that for a restricted class of default theories,there is some kind of correspondence between Yager's formalism and Reiter's default logic.We point out that there are many mismatches between them for general default theories.Finally,we propose the fixed point mechanism as an improved scheme to eliminate such mismatches.