Algorithms and Algorithm Analysis of Logical Difference Operation of Variable Precision Lower Approximation Operator and Grade Upper Approximation Operator

This paper aims to construct new operation of approximation operators, and explore its calculation. First it proposes logical difference operation of variable precision lower approximation operator and grade upper approximation operator. Then regular algorithm and structural algorithm are proposed and analyzed, and furthermore, a conclusion is drawn that structural algorithm has advantages in time complexity and space complexity. Finally a practical example is given to illustrate the new operation and its algorithms.