An incremental approach for updating approximations of neighborhood rough fuzzy sets under the variation of object set

The lower and upper approximations are basic concepts in rough set theory, and they will change dynamically over time. Neighborhood rough fuzzy set is an extension of rough set theory. This paper aims to present a new approach for updating approximations incrementally in dynamic neighborhood fuzzy decision systems when a single object immigrating and emigrating. Examples are given to illustrate the proposed approach.