Comparison Research on Fuzzy Set,Rough Set and Quotient Space Theory

The fuzzy set,rough set and quotient space theory are compared in details from the viewpoints of understanding of intelligence,representation of granules,measurement of granules and relationship among granules.Their commons are to think problem from a granular perspective,to define a granule by a set and to represent a knowledge by a granule;their main difference is that theory of computing with words and rough set theory focus on reasoning of words and attribute reduction from microcosmic level respectively,while quotient space theory discusses the translation rules of granules among the worlds with different grain-size from macrocosmic level.