Abstract
A recent Journal of Scheduling paper by Chen and Zhang (J Sched, 2020. https://doi.org/10.1007/s10951-020-00668-1) proves that the problem of scheduling coupled tasks to minimize total completion time is NP-hard in the strong sense even for the case with all tasks having the same, though not necessarily unit, processing times. This note shows a simpler proof of that result, and strengthens it by proving that the problem is NP-hard in the strong sense even if all tasks are unit-time.
References
Chen, B., & Zhang, X. (2020). Scheduling coupled tasks with exact delays for minimum total job completion time. Journal of Scheduling. https://doi.org/10.1007/s10951-020-00668-1.
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Kubiak, W. A note on scheduling coupled tasks for minimum total completion time. Ann Oper Res 320, 541–544 (2023). https://doi.org/10.1007/s10479-022-04706-3
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DOI: https://doi.org/10.1007/s10479-022-04706-3