On the Srikar-Ghosh MILP model for the N×N SDST flowshop problem

This paper reports corrections to the Srikar and Ghosh MILP model for the SDST (sequence dependent set-up times) flowshop model. Included is the correct formulation for minimizing mean flow time of the set of jobs. A condition under which SDST problems can be optimized by this model, even when the triangular inequality of set-up times is violated, is derived. Three new MILP flowshop models, inspired by the study of the Srikar and Ghosh work, are presented.