Optimization of fuzzy simple inventory models

We introduce two fuzzy simple inventory models with fuzzy parameters and fuzzy variables that are generalized trapezoidal fuzzy numbers. We use the second function principle, graded mean integration representation method, and an extension of the Lagrangean method to find optimal fuzzy economic order quantities of each fuzzy inventory model. The solutions of fuzzy inventory models are quite good and can be specified to meet the classical inventory models by using these useful and executable methods. Another result is that the economic order quantities of the fuzzy inventory model with crisp order quantity, and with fuzzy order quantity are all crisp real numbers.