Approaches for incrementally updating approximations based on set-valued information systems while attribute values´ coarsening and refining

Incrementally updating approximations in rough set theory may contribute to enhancement of the efficiency of knowledge discovery. This paper firstly introduces the definitions of attribute values´ coarsening and refining in set-valued information systems. Then the approach for incrementally updating approximations of a concept is presented while attribute values coarsening and refining. Finally, an example is presented to illustrate the validity of the proposed approach.