Abstract: The terms of essential attribute, attached attribute and restrictive attribute are defined in formal language, their properties and intrinsic links are discussed, and a new classification method is obtained. In conjunction with a new operation for subset of attribute, the characteristic of essential attribute is discussed in particular, and thus the notion of kind in IDEF5 is amended formally. Simultaneously, when there are a plurality of essential attributes, research shows that only one should be reserved, any other item must be reducible attribute and also unnecessary attribute, while the verification of essential attribute is simple and easy, part of attributes can be eliminated before utilizing some algorithm to process attribute reduction. Finally, an example is used to illustrate the advantage of such preprocessing.

Key words: formal concept analysis, attribute reduction, restrictive attribute, kind, essential attribute, preprocessing, reducible attribute, attribute classification

摘要： 以形式化语言给出了本质属性、附属属性、限定性属性等术语的定义，研究了它们的性质与内在联系，给出了属性集的一种新的分类方法。结合对属性子集的一种新运算，特别讨论了本质属性的特征，并以此对IDEF5中种类的概念做了形式化修正。同时，研究发现，在本质属性为多个时，只需保留一条，其他任何一条本质属性既是可约属性也是不必要属性，而本质属性的判定简便易行，在利用相关算法进行属性约简之前可以先剔除部分属性。最后，以实例表明了这样预处理的优越性。

关键词: 形式概念分析, 属性约简, 限定性属性, 种类, 本质属性, 预处理, 可约属性, 属性分类