Product Operation of Grade Lower Approximation Operator and Grade Upper Approximation Operator Based on Two Parameters
Xianyong Zhang, Fang Xiong, Zhiwen Mo · 2010
Grade is an important quantitative index, and graded rough set model is an important improved rough set model. This paper is to explore product operation of grade approximation operators. Based on logical product operation, this paper proposes product operation of grade lower approximation operator and grade upper approximation operator based on two parameters. Essence, basic structure and properties are obtained. Macroscopic algorithm and structural algorithm are proposed and analyzed, and by comparison it obtains an important conclusion that structural algorithm has advantages in time complexity and space complexity. Finally an example is given to illustrate the product operation and its algorithms.