Abstract: Nowadays there exists several extensions for rough set theory to handle incomplete information systems, such as tolerance relation model, similarity relation model and other models derived from the former two. Presented in this paper is an improved rough set based on limited tolerance relation with the concept of a maximal compatible class. The new model, which is called rough set based on L_A maximal compatible classes, creates a better approximation accuracy. At last, attributes reduct in this new model is discussed.

Key words: incomplete information system, rough set, limited tolerance relation, maximal compatible class, attribute reduct

摘要： 目前处理不完备信息系统已经有了容差关系、相似关系等推广的粗糙集模型，以及这两种模型的改进形式。基于限制容差关系，提出了一种新的相容类的概念——L_A最大相容类，并建立L_A最大相容类粗糙集模型。通过对比分析得出L_A最大相容类粗糙集模型可以获得更高的近似精度，并讨论了在此模型下属性的约简问题。

关键词: 不完备信息系统, 粗糙集, 限制容差关系, 最大相容类, 属性约简