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On Niu's Conjecture for Two-Station Tandem Queues
Abstract
In this paper, we prove a long standing conjecture in queueing theory made by Niu (1980): in a two-station tandem queueing system with constant service time (c) at station 1, the stationary average waiting time at station 2 is nonincreasing in c. Two very different proofs are provided: one for the general case and one for a special case in which the arrival process is Poisson and the service time at station 2 is exponential.
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BibTeX
@misc{cao2026nius,
title = {{On Niu's Conjecture for Two-Station Tandem Queues}},
author = {Hao Cao and Jian-Qiang Hu and Qixin Wang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.22837},
eprint = {2610.22837},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.22837},
}
RIS
TY - UNPB
TI - On Niu's Conjecture for Two-Station Tandem Queues
AU - Hao Cao
AU - Jian-Qiang Hu
AU - Qixin Wang
PY - 2026
DA - 2026/10/16
PB - arXiv
DO - 10.48550/arxiv.2610.22837
UR - https://arxiv.org/abs/2610.22837
AB - In this paper, we prove a long standing conjecture in queueing theory made by Niu (1980): in a two-station tandem queueing system with constant service time (c) at station 1, the stationary average waiting time at station 2 is nonincreasing in c. Two very different proofs are provided: one for the general case and one for a special case in which the arrival process is Poisson and the service time at station 2 is exponential.
ER -