Roughness in rings
In this paper basic notions of the rough set theory will be given. In fact, the paper concerns a relationship between rough sets and ring theory. We shall introduce the notion of rough subring (resp. ideal) with respect to an ideal of a ring which is an extended notion of a subring (resp. ideal) in a ring, and we shall give some properties of the lower and the upper approximations in a ring.
rough set rough subring upper approximation lower approximation rough ideal