Kabakulak, Banu2022-11-112022-11-1120222472-5854https://hdl.handle.net/11411/4668https://doi.org/10.1080/24725854.2021.2022250Abstract: We consider an uncapacitated lot-sizing problem in co-production systems, in which it is possible to produce multiple items simultaneously in a single production run. Each product has a deterministic demand to be satisfied on time. The decision is to choose which items to co-produce and the amount of production throughout a predetermined planning horizon. We show that the lot-sizing problem with co-production is strongly NP-Hard. Then, we develop various Mixed-Integer Linear Programming (MILP) formulations of the problem and show that LP relaxations of all MILPs are equal. We develop a separation algorithm based on a set of valid inequalities, lower bounds based on a dynamic lot-sizing relaxation of our problem and a constructive heuristic that is used to obtain an initial solution for the solver, which form the basis of our proposed Branch & Cut algorithm for the problem. We test our models and algorithms on different data sets and provide the results. © Copyright © 2022 “IISE”.eninfo:eu-repo/semantics/openAccessbranch & cutCo-productionlot-sizingMILPArticle2-s2.0-8512441107810.1080/24725854.2021.2022250Q1WOS:000754103800001