Note---Comments on “Single Cycle Continuous Review Policies for Arborescent Production/Inventory Systems”

In the paper by Graves and Schwarz [Graves, Stephen C., Leroy B. Schwarz. 1977. Single cycle continuous review policies for arborescent production/inventory systems. Management Sci.23 5, January 529--540.], we observed an error in their discussion of optimal policies for the one warehouse-m retailer system. Specifically, Theorem 1, which states that the optimal stationary policy is a single-cycle policy, is incorrect.