Abstract: In this paper, the incomplete information system in which attributes values were considered as interval grey number. Firstly, some operation properties of interval grey number were presented according to the definition of interval grey number, and an incomplete grey information system was defined. Then, based on grey similar degree, the variable precise grey similar relation was proposed, and the upper and lower approximations were conducted according to variable precise grey similar relation. Lastly, a practical operation method for computing reduction was given, and the validity of the proposed technique was verified via a typical case.

Key words: rough set, grey number, grey information system, grey similar relation, knowledge reduction

摘要： 提出一种属性值为区间灰数的不完备信息系统。首先根据区间灰数的定义，提出了区间灰数的一些运算性质，并定义了不完备灰色信息系统；然后，根据灰相似度，提出了变精度灰相似关系，并根据变精度灰相似关系引出了上、下近似算子；最后给出了约简的实际操作方法，并通过典型例子验证了该方法的有效性。

关键词: 粗糙集, 灰数, 灰色信息系统, 灰相似关系, 知识约简