Retailer's lot-sizing policy under two warehouses and two levels of delay permitted using algebraic method

The main purpose of this paper is to modify Huang's model by considering two warehouses. In addition, we try to use algebraic method to determine the optimal lot-sizing policy for the retailer under two warehouses and two levels of delay permitted. This paper provides this algebraic approach that could be used easily to introduce the basic inventory theories to younger students who lack the knowledge of calculus.