Randomized $k$-server in polynomial time

Fuente: arXiv
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Autori principali: Coester, Christian, Cosson, Romain
Natura: Preprint
Pubblicazione: 2026
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author Coester, Christian
Cosson, Romain
author_facet Coester, Christian
Cosson, Romain
contents We study the design of computationally efficient randomized algorithms for the $k$-server problem. Existing randomized algorithms with the best known competitive ratios are, on the one hand, inherently implicit and, on the other hand, employ a rounding scheme that maintains a distribution over exponentially many configurations. In this work, we introduce a derandomization framework that transforms any randomized $k$-server algorithm on a hierarchically separated tree into one that uses only $O(\log k)$ random bits for request sequences of arbitrary length; hence maintaining a distribution over only polynomially many server configurations. Leveraging this black-box derandomization, we obtain the first polynomial-time randomized $k$-server algorithm on arbitrary $n$-point metrics with a polylogarithmic competitive ratio. Our results also have implications for the advice complexity of the $k$-server problem.
format Preprint
id arxiv_https___arxiv_org_abs_2605_01497
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Randomized $k$-server in polynomial time
Coester, Christian
Cosson, Romain
Data Structures and Algorithms
We study the design of computationally efficient randomized algorithms for the $k$-server problem. Existing randomized algorithms with the best known competitive ratios are, on the one hand, inherently implicit and, on the other hand, employ a rounding scheme that maintains a distribution over exponentially many configurations. In this work, we introduce a derandomization framework that transforms any randomized $k$-server algorithm on a hierarchically separated tree into one that uses only $O(\log k)$ random bits for request sequences of arbitrary length; hence maintaining a distribution over only polynomially many server configurations. Leveraging this black-box derandomization, we obtain the first polynomial-time randomized $k$-server algorithm on arbitrary $n$-point metrics with a polylogarithmic competitive ratio. Our results also have implications for the advice complexity of the $k$-server problem.
title Randomized $k$-server in polynomial time
topic Data Structures and Algorithms
url https://arxiv.org/abs/2605.01497