Fuzzy inventory model for deteriorating items with permissible delay in payment

In this paper, we extend Jamal et al. [A.M.M. Jamal, BR. Sarker, S. Wang, An ordering policy for deteriorating items with allowable shortage and permissible delay in payment, Journal of Operations Research Society 48 (1997) 826-833.] model by fuzzifying the carrying cost rate, interest paid rate and interest earned rate simultaneously, based on the interval-valued fuzzy numbers and triangular fuzzy number to fit the real world. We then prove that the estimate of total variable cost per unit time in the fuzzy sense is a strictly pseudo-convex function. As a result, there exists a unique optimal solution to our proposed model. Moreover, we apply the Jamal et al. example to show the results and to compare with the Jamal et al. model. (c) 2006 Elsevier Inc. All rights reserved.