The Fuzzy Rough Set Theory And Its Application In Group

There are many uncertainty problems in our life.The theory of fuzzy set and rough set are a kind of tools to solve uncertainty.Rough set theory and fuzzy set theory have formed a relatively complete theoretical system.Some of scholars have achieved important research results in China,and these results have attracted the attention of the academia.When we in deal with complex information,we need to find useful information for us,we could use the rough fuzzy sets and fuzzy rough set models to deal with these comples information problems.So,our main works as follows:First,we defined the upper and lower approximations by combine the rough set theory and rough set theory.We discussed some basic properties of the fuzzy homomorphism of a rough fuzzy group.Second,we construct a fuzzy approximation space.In this space,we can define the upper and lower approximations about a fuzzy rough set model.We study the lower and upper approximations.At last,I discussed the basic properties about this model.Third,we find a new model about a fuzzy rough set based on a covering.So some properties can be discussed about group.Fourth,we study a new kind of the representation of multi-granulation problem of fuzzy rough set.In this model,we defined of upper and lower approximation set,so some interesting conclusions of the multi-granularity fuzzy rough sey.In this paper,the research results are not only to enrich and improve the theory of fuzzy rough set and rough fuzzy set,but also to improve a basis for further study.