We define a new kind of fuzzy numbers——Quadratic Lateral Edge Trapezoid Fuzzy Number(QLETFN) in order to provide more options on the selection of discount function coefficients,and estimate the term structure of fuzzy interest rate using fuzzy linear regression to increase the reliability of our result.

Based on principles of fuzzy clustering analysis,the paper classifies the economy of 31 provinces of China using relation of fuzzy equivalence and F-statistical analysis.

The concept of fuzzy equality [1], which is also called the equality relation[2,3], the fuzzy equivalence relation [4], the similarity relation [5,6] and the indistinguishable operator [7,8], and the fuzzy functions based on fuzzy equalities, has a significant concern in various fields, such as category theory and fuzzy control.

By means of formulation for fuzzy addition and fuzzy equation,the production-inventory balance equations in single stage and dynamic balance equations were formulated as a soft equation in terms of a degree of truth and interpreted as the possibility level of which production and inventory plan met the fuzzy demand.