Covering fuzzy rough set based on multi-granulations

This paper extends the rough set model based on multi-granulations to the covering fuzzy rough set model based on multi-granulation, which is named MGCFRS. The lower and upper approximations of fuzzy sets in a covering approximation space are defined and some basic properties about the MGCFRS are investigated. One can see that the basic properties of MGRS are special cases of MGCFRS model.