Minmax due-date assignment on a two-machine flowshop

We extend two classical scheduling and due-date assignment models. In the first (known in the literature as DIF), due-dates are determined by penalties for exceeding pre-specified deadlines. In the second (known as SLK), due-dates are assigned to jobs as a (linear) function of their processing times. We focus on the minmax versions of these models, and extend the single machine versions to a two-machine flowshop. We further extend the settings to that of a due-window. All the problems studied in this note are shown to have polynomial time solutions.