Lopes, Isabel CristinaCarvalho, J. M. Valerio de2015-04-242015-04-2420101992-9978e-ISSN 1992-9978http://hdl.handle.net/10400.22/5827In this paper we address an order processing optimization problem known as the Minimization of Open Stacks Problem (MOSP). This problem consists in finding the best sequence for manufacturing the different products required by costumers, in a setting where only one product can be made at a time. The objective is to minimize the maximum number of incomplete orders from costumers that are being processed simultaneously. We present an integer programming model, based on the existence of a perfect elimination order in interval graphs, which finds an optimal sequence for the costumers orders. Among other economic advantages, manufacturing the products in this optimal sequence reduces the amount of space needed to store incomplete orders.engInteger programmingInterval graphsOpen orders minimizationMOSPPathwidthjournal article