关键词: 粗糙集, 信息系统, 下近似约简, 辨识矩阵

Abstract: The concept of lower approximation reduction is introduced in information systems based on dominance relations.And the judgment theorem and discernable matrix are obtained，from which authors can effectively provide the approach to this reduction in inconsistent systems based on dominance relations.Finally，an example illustrates the validity of this method.The proposed framework constructs efficient theoretical basis for knowledge discovery in information systems based on dominance relations.

Key words: rough set, information system, lower approximation reduction, discernable matrix