Abstract: Tolerance relations are defined in inconsistent set-valued information systems.Based on tolerance relations，the assignment reduction and approximation reduction are introduced and the relationship between them is discussed in inconsistent set-valued information systems.The judgment theorem and discernable matrix of them are obtained and a new approach is proposed for the assignment reduction and approximation reduction in inconsistent set-valued information systems based on tolerance relations.The validity of this approach is illustrated by a numerical example.

Key words: set-valued information system, knowledge reduction, discernable matrix, assignment reduction, approximation reduction

摘要： 在不协调集值目标信息系统中定义了相容关系，并在基于相容关系的不协调集值目标信息系统中引入分配约简和近似约简的概念，讨论了二者之间的关系，并且得到了分配约简和近似约简的判定定理以及辨识矩阵，建立了不协调集值目标信息系统的分配和近似约简的具体方法，同时通过实例验证了该方法的有效性。

关键词: 集值目标信息系统, 知识约简, 辨识矩阵, 分配约简, 近似约简