Transportation problem (TP) is well-known basic network problem which can be generally defined as the problem that calculates the optimal amount of deliveries. Until now, in order to apply to the real world, the TP model is extended to satisfy other additional constraints or performed in several stages. However, the concept of inventory is not considered in a traditional TP. Moreover, time concepts, such as a carrying cost in a certain period, are not included. And today's distribution channel becomes a flexible form. In this study, we formulate a flexible logistics network model with inventory. In this model, the network...