比较知识库精细关系的两种不同定义,得出等价关系与划分、二元关系与覆盖、以及二元关系与覆盖约简之间的一些有趣联系;进而探讨这两种定义在粗糙集中对提高知识确定性程度的不同作用。这些结论将对基于粗糙集的不确定性研究提供一定的帮助。 By comparing two different definitions of fine relationship in knowledge base, some interesting relations between equivalence relation and division, binary relation and coverage, and binary relation and coverage reduction are obtained. Then we discuss the relationship between these two definitions in rough set The different roles of improving the certainty of knowledge. These conclusions will be helpful to the research of uncertainty based on rough sets.