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The theory of rough sets is an extension of set theory with two additional unary set-theoretic operators deened based on a binary relation on the universe. These two operators are related to the modal operators in modal logics. By exploring the relationship between rough sets and modal logics, this paper proposes and examines a number of extended rough set(More)
<italic>Computer are finite discrete machines, the set of real numbers is an infinite continuum. So real numbers in computers are approximation. Rough set theory is the underlying mathematics. A &#8220;computer&#8221; version of Weistrass theorem states that every sequence, within the radius of error, repeats certain terms infinitely many times. In terms of(More)
Topological data models. One of the most important goals of data modeling is to capture the information requirements of an application in terms of structures, constrains, and operations that naturally reflect the real world situation. To date Codd's relational data modeling has been one of the most successful representations of real world problems. As(More)