COMPLEXITY OF SCHEDULING SHOPS WITH NO WAIT IN PROCESS.

Abstract

The authors show that obtaining minimum finish time schedules with no wait in process is NP-Hard for flow shops, job shops and open shops. Specifically, it is shown that the two processor job and open shop problems are NP-Hard even when jobs are restricted to have no task of length zero. The two processor flow shop problem is NP-Hard if jobs with only one task are permitted. It should be noted that P. Gilmore and R. Gomory have obtained a polynomial time algorithm for the two processor flow shop for the case where every job has two tasks. The 4-sum and 2-pair problems are also shown NP-Hard.