Abstract
In this paper, we derive two equations to calculate averages of certainty and coverage of decision rules in variable precision rough set (for short, VPRS) models proposed by Ziarko.
VPRS is an extension of Pawlak's rough set theory, and it
provides a theoretical basis to treat inconsistent or
probabilistic information in the framework of rough sets.
Many kinds of attribute reduction in VPRS
have also been proposed, however, studies of evaluation criteria
of reducts in VPRS have not been widely investigated.
On the other hand, the authors have proposed an evaluation criterion
of relative reducts in Pawlak's rough set by using
averages of coverage of decision rules constructed from relative reducts.
Thus, we intend that the derived two equations are basis to apply the authors' evaluation criterion of relative reducts to many kinds of reducts in VPRS, and the derived equations also include the similar equations in the case of Pawlak's rough set that the authors have proposed.
