A new method for calculation of the approximations under the probabilistic rough sets

The rough set theory (RST) can deal with the approximations of an arbitrary subset of a universe by two definable subsets called, respectively, the lower and the upper approximations. Probabilistic rough sets (PRS) model is an extension of RST. In this paper, we propose a new matrix view of PRS and give the matrix representation of the lower and upper approximations of PRS. According to this matrix view, a new method is obtained for calculation of the lower and upper approximations under PRS. An example is given to illustrate processes of calculating the approximations of a concept based on the matrix point of view.