证明了对象(属性)概念的外延(内涵)是构成概念外延(内涵)的基本单住,由此提供了通过外延(内涵)基本元来构造形式概念的方法。定义了几种基于外延基本元和内涵基本元的上、下近似,给出了近似算子的性质,并讨论了这些近似算子之间的相互关系。
This paper proves that all the extents(intents) of object-concepts (attribute-concepts) are the basicelements of extent sets (intent sets). We then obtain a method toconstructing concepts in a formal context. Based on the basicelements of extents and intents, some new concepts of upper andlower approximation operators are introduced. The basic propertiesof these operators are discussed, and the relationships among someexisted concepts of rough approximations are also studied.