• Corpus ID: 126088243

On the Min-Max-Delay Problem: NP-completeness, Algorithm, and Int-Gap

@article{Liu2017OnTM,
  title={On the Min-Max-Delay Problem: NP-completeness, Algorithm, and Int-Gap},
  author={Qingyu Liu and Lei Deng and Haibo Zeng and Minghua Chen},
  journal={ArXiv},
  year={2017},
  volume={abs/1707.02650}
}

• Qingyu Liu, Lei Deng, +1 author Minghua Chen
• Published 9 July 2017
• Computer Science, Mathematics
• ArXiv

We study a delay-sensitive information flow problem where a source streams information to a sink over a directed graph G(V,E) at a fixed rate R possibly using multiple paths to minimize the maximum end-to-end delay, denoted as the Min-Max-Delay problem. Transmission over an edge incurs a constant delay within the capacity. We prove that Min-Max-Delay is weakly NP-complete, and demonstrate that it becomes strongly NP-complete if we require integer flow solution. We propose an optimal pseudo-polynomial time algorithm for Min-Max-Delay, with time complexity O(\log (Nd_{\max}) (N^5d_{\max}^{2.5})(\log R+N^2d_{\max}\log(N^2d_{\max}))), where N = \max\{|V|,|E|\} and d_{\max} is the maximum edge delay. Besides, we show that the integrality gap, which is defined as the ratio of the maximum delay of an optimal integer flow to the maximum delay of an optimal fractional flow, could be arbitrarily large.