FUZZY SET THEORY
In mathematics , fuzzy sets (a.k.a. uncertain sets ) are sets whose elements have degrees of membership. Fuzzy sets were introduced independently by Lotfi A. Zadeh in 1965 as an extension of the classical notion of set. [1] [2] At the same time, Salii (1965) defined a more general kind of structure called an L -relation , which he studied in an abstract algebraic context. Fuzzy relations, which are now used throughout fuzzy mathematics and have applications in areas such as linguistics ( De Cock, Bodenhofer & Kerre 2000 ), decision-making ( Kuzmin 1982 ), and clustering ( Bezdek 1978 ), are special cases of L -relations when L is the unit interval [0, 1]. In classical set theory , the membership of elements in a set is assessed in binary terms according to a bivale...