Simultaneously scheduling n jobs and the preventive maintenance on the two-machine flow shop to minimize the makespan (vol 112, pg 161, 2008)

In Allaoui et al. (2008), 'Simultaneously scheduling n jobs and the preventive maintenance on the two-machine flow shop to minimize the makespan' published in the International journal of Production Economics, the authors show that the problem of two machine flow shop scheduling with a single maintenance occurring on the second machine is NP-hard (Theorem 7). In this Erratum we establish that this theorem is false and provide a polynomial time algorithm to solve this problem. An extension is proposed for further research in this area. We also highlight that the proof of Proposition 6 is incorrect and we propose a new proof for this proposition. (C) 2014 Elsevier B.V. All rights reserved.