群中上近似集性质的一种新的简洁证法

A New Brief Proof of the Properties of the Upper Approximation in a Group

Nobuaki Kuroki在文[3]中研究了群中粗糙集的上下近似集的性质.但是他的很多结果的证明依赖于上下近似集的定义,从这个角度去证明是很繁琐的,并且很多结果是可以进一步推广得更深刻一些的.文章给出了群中上近似集性质的一种简洁证法,并且推广了上近似集的一些性质.

The Lower and upper approximations in a group was studied by Nobuaki Kuroki.But his proofs of some results depends on the definition of the lower and upper approximation which is not brief. And some results can been extended .This paper gives a more brief proof of the properties of the upper approximation .extends the properties of the upper approximation.