Algorithm of upper and lower approximations based on matrix
基于矩阵的粗糙集上、下近似求解算法*

This paper mainly discuss the problem about the calculation of upper and lower approximations in Rough Set Theory. Because a relation can be represented by a matrix and matrix operations are simple and intuitive, a new method about the calculation of upper and lower approximations was proposed based on relation martix and martix operations.The theoretical proof shows that the method is feasible and effective.