Rough sets on fuzzy approximation spaces and applications to distributed knowledge systems
D. P. Acharjya, Bala Krushna Tripathy · International Journal of Artificial Intelligence and Soft Computing · 2008
A fuzzy relation is an extension of crisp relation on any set U. Fuzzy proximity relations on U are much more general and abundant than equivalence relations. The fuzzy approximation space which depends upon a fuzzy proximity relation defined on a set U is a generalisation of the concept of knowledge base. So, rough sets defined on fuzzy approximation spaces extend the concept of rough sets on knowledge bases. The results of the present paper extend the basic properties of rough sets and results involving set theoretic operations on types of rough sets that have been established in Tripathy and Mitra (2008).