Evidence Theory and VPRS model

The Rough Set Theory (RST) was proposed by Pawlak 4] as a new mathematical approach to deal with uncertain knowledge in expert systems. In 1991 Ziarko 11] proposed the Variable Precision Rough Set Model (VPRSM) as a certain extension of the rough set theory. VPRSM approach makes it possible to use a certain level of misclassification.The aim of this paper is to introduce belief and plausibility functions defined by the β-approximation regions. On the basis of the β-approximation regions, the β-basic probability assignment is defined and the Dempster's combination rule for product of two decision tables is constructed. This entire approach is illustrated by examples.