Aset j of jobs are to be scheduled on m identical machines. each job j 2 j has a processing requirement pj (denoting the number of machine days required to complete the job), a release date rj (representing the beginning of the day when job j becomes available for processing), and a due date dj rj + pj (representing the beginning of the day by which the job must be completed). we assume that a machine can work on only one job at a time and that each job can be processed by at most one machine at a time. however, we allow preemptions (i. e., we can interrupt a job and process it on di§erent machines on di§erent days). the scheduling problem is to determine a feasible schedule that completes all jobs before their due dates or to show that no such schedule exists. formulate this problem as a maximum áow problem.