This paper addresses the single stage lot-sizing problem in parallel machines. Each item can be produced on any machine, and incurs a setup time before to start the production. The objective of this paper is to obtain lower bounds of good quality for this problem. A solution method is developed based on a reformulation of the problem and the Lagrangian relaxation of a set of constraints. Some computational results are presented comparing the proposed method with a method from the literature and with a computational package.
Lot sizing; parallel machines; lower bounds
