Abstract
The identification problem which plays a central role in further development of the theory of fuzzy systems and their applications is considered. The systems under consideration are of the type XRY or (X1X2 . . . Xn)RY, where X, X1, X2, . . ., X n, denote fuzzy sets of input and Y stands for fuzzy set of output, while R denotes a fuzzy relation expressing the relationships between input and output. Appropriate methods of determination of fuzzy relations are presented. The idea of probabilistic sets in the identification problem is discussed in detail.