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Related papers: k-server via multiscale entropic regularization

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We exhibit an $O((\log k)^6)$-competitive randomized algorithm for the $k$-server problem on any metric space. It is shown that a potential-based algorithm for the fractional $k$-server problem on hierarchically separated trees (HSTs) with…

Data Structures and Algorithms · Computer Science 2021-07-30 James R. Lee

We study the randomized k-server problem on metric spaces consisting of widely separated subspaces. We give a method which extends existing algorithms to larger spaces with the growth rate of the competitive quotients being at most O(log…

Data Structures and Algorithms · Computer Science 2007-08-20 Judit Nagy-György

We consider metrical task systems on tree metrics, and present an $O(\mathrm{depth} \times \log n)$-competitive randomized algorithm based on the mirror descent framework introduced in our prior work on the $k$-server problem. For the…

Data Structures and Algorithms · Computer Science 2020-11-30 Sébastien Bubeck , Michael B. Cohen , James R. Lee , Yin Tat Lee

We give the first polylogarithmic-competitive randomized online algorithm for the $k$-server problem on an arbitrary finite metric space. In particular, our algorithm achieves a competitive ratio of O(log^3 n log^2 k log log n) for any…

Data Structures and Algorithms · Computer Science 2011-10-10 Nikhil Bansal , Niv Buchbinder , Aleksander Madry , Joseph , Naor

We study the $k$-server problem in the resource augmentation setting i.e., when the performance of the online algorithm with $k$ servers is compared to the offline optimal solution with $h \leq k$ servers. The problem is very poorly…

Data Structures and Algorithms · Computer Science 2017-04-12 Nikhil Bansal , Marek Eliáš , Łukasz Jeż , Grigorios Koumoutsos

We consider the $k$-server problem on trees and HSTs. We give an algorithm based on Bregman projections. This algorithm has a competitive ratios that match some of the recent results given by Bubeck et al. (STOC 2018), whose algorithm was…

Data Structures and Algorithms · Computer Science 2018-12-21 Niv Buchbinder , Anupam Gupta , Marco Molinaro , Joseph , Naor

We show that on every $n$-point HST metric, there is a randomized online algorithm for metrical task systems (MTS) that is $1$-competitive for service costs and $O(\log n)$-competitive for movement costs. In general, these refined…

Data Structures and Algorithms · Computer Science 2020-09-04 Christian Coester , James R. Lee

We consider the online $k$-taxi problem, a generalization of the $k$-server problem, in which $k$ taxis serve a sequence of requests in a metric space. A request consists of two points $s$ and $t$, representing a passenger that wants to be…

Data Structures and Algorithms · Computer Science 2018-11-07 Christian Coester , Elias Koutsoupias

We consider online algorithms for the $k$-server problem on trees. There is a $k$-competitive algorithm for this problem, and it is the best competitive ratio. M. Chrobak and L. Larmore provided it. At the same time, the existing…

Data Structures and Algorithms · Computer Science 2022-05-02 Kamil Khadiev , Maxim Yagafarov

In this paper, we show that there is an O(log k log^2 n)-competitive randomized algorithm for the k-sever problem on any metric space with n points, which improved the previous best competitive ratio O(log^2 k log^3 n log log n) by Nikhil…

Data Structures and Algorithms · Computer Science 2015-10-28 Wenbin Chen

We study the resource augmented version of the $k$-server problem, also known as the $k$-server problem against weak adversaries or the $(h,k)$-server problem. In this setting, an online algorithm using $k$ servers is compared to an offline…

Data Structures and Algorithms · Computer Science 2020-04-22 Marcin Bienkowski , Jarosław Byrka , Christian Coester , Łukasz Jeż

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,…

Data Structures and Algorithms · Computer Science 2026-05-05 Christian Coester , Romain Cosson

The generalized $k$-server problem is an extension of the weighted $k$-server problem, which in turn extends the classic $k$-server problem. In the generalized $k$-server problem, each of $k$ servers $s_1, \dots, s_k$ remains in its own…

Data Structures and Algorithms · Computer Science 2019-09-18 Marcin Bienkowski , Łukasz Jeż , Paweł Schmidt

A natural variant of the classical online $k$-server problem is the Weighted $k$-server problem, where the cost of moving a server is its weight times the distance through which it moves. Despite its apparent simplicity, the weighted…

Data Structures and Algorithms · Computer Science 2024-10-10 Nikhil Ayyadevara , Ashish Chiplunkar , Amatya Sharma

In this paper, we settle the randomized $k$-sever conjecture for the following metric spaces: line, circle, Hierarchically well-separated tree (HST). Specially, we show that there are $O(\log k)$-competitive randomized $k$-sever algorithms…

Data Structures and Algorithms · Computer Science 2015-10-28 Wenbin Chen

We prove a few new lower bounds on the randomized competitive ratio for the $k$-server problem and other related problems, resolving some long-standing conjectures. In particular, for metrical task systems (MTS) we asympotically settle the…

Data Structures and Algorithms · Computer Science 2023-07-07 Sébastien Bubeck , Christian Coester , Yuval Rabani

The weighted $k$-server is a variant of the $k$-server problem, where the cost of moving a server is the server's weight times the distance through which it moves. The problem is famous for its intriguing properties and for evading standard…

Data Structures and Algorithms · Computer Science 2025-10-28 Adithya Bijoy , Ankit Mondal , Ashish Chiplunkar

We consider the online $k$-taxi problem, a generalization of the $k$-server problem, in which $k$ servers are located in a metric space. A sequence of requests is revealed one by one, where each request is a pair of two points, representing…

Data Structures and Algorithms · Computer Science 2020-12-07 Niv Buchbinder , Christian Coester , Joseph , Naor

We develop a new approach for online network design and obtain improved competitive ratios for several problems. Our approach gives natural deterministic algorithms and simple analyses. At the heart of our work is a novel application of…

Data Structures and Algorithms · Computer Science 2014-10-17 Seeun Umboh

The weighted $k$-server problem is a generalization of the $k$-server problem in which the cost of moving a server of weight $\beta_i$ through a distance $d$ is $\beta_i\cdot d$. The weighted server problem on uniform spaces models caching…

Data Structures and Algorithms · Computer Science 2016-11-15 Ashish Chiplunkar , Sundar Vishwanathan
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