Brucker, Peter; Kravchenko, Svetlana A.; Sotskov, Yuri N. - In: Computational Statistics 49 (1999) 1, pp. 41-76
It is shown that the two machine preemptive job-shop problem with mean flow-time or makespan objective function and three jobs is NP-hard. This contrasts the fact that the nonpreemptive versions of these problems are polynomially solvable if the number of jobs is arbitrary but fixed. It is also...