Variable Fuzzy Methods and Mistake Demonstration in Extension Dependence Function

The paper presents two expressive forms of variable fuzzy sets definition, and proposes variable fuzzy method. These two forms are kernel of variable fuzzy sets theory and mathematical base of fuzzy hydrology and water resources;they can be used for different fields. From theory and applicationthe author also uses illustrationto verify mistakes of basic formula of extension dependent function which taking concepts of "distance"and "location values"as foundation, and points out that it can not be applied in engineering fields of hydrology, water resources and hydropower.