Stronger adversaries grow cheaper forests: online node-weighted Steiner problems

Fuente: arXiv
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Autores principales: Borst, Sander, Eliáš, Marek, Venzin, Moritz
Formato: Preprint
Publicado: 2024
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author Borst, Sander
Eliáš, Marek
Venzin, Moritz
author_facet Borst, Sander
Eliáš, Marek
Venzin, Moritz
contents We propose a $O(\log k \log n)$-competitive randomized algorithm for online node-weighted Steiner forest. This is essentially optimal and significantly improves over the previous bound of $O(\log^2 k \log n)$ by Hajiaghayi et al. [2017]. In fact, our result extends to the more general prize-collecting setting, improving over previous works by a poly-logarithmic factor. Our key technical contribution is a randomized online algorithm for set cover and non-metric facility location in a new adversarial model which we call semi-adaptive adversaries. As a by-product of our techniques, we obtain the first deterministic $O(\log |C| \log |F|)$-competitive algorithm for non-metric facility location.
format Preprint
id arxiv_https___arxiv_org_abs_2410_18542
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Stronger adversaries grow cheaper forests: online node-weighted Steiner problems
Borst, Sander
Eliáš, Marek
Venzin, Moritz
Data Structures and Algorithms
We propose a $O(\log k \log n)$-competitive randomized algorithm for online node-weighted Steiner forest. This is essentially optimal and significantly improves over the previous bound of $O(\log^2 k \log n)$ by Hajiaghayi et al. [2017]. In fact, our result extends to the more general prize-collecting setting, improving over previous works by a poly-logarithmic factor. Our key technical contribution is a randomized online algorithm for set cover and non-metric facility location in a new adversarial model which we call semi-adaptive adversaries. As a by-product of our techniques, we obtain the first deterministic $O(\log |C| \log |F|)$-competitive algorithm for non-metric facility location.
title Stronger adversaries grow cheaper forests: online node-weighted Steiner problems
topic Data Structures and Algorithms
url https://arxiv.org/abs/2410.18542