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Related papers: k-server via multiscale entropic regularization

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We study a variant of the $k$-server problem, the infinite server problem, in which infinitely many servers reside initially at a particular point of the metric space and serve a sequence of requests. In the framework of competitive…

Data Structures and Algorithms · Computer Science 2017-03-01 Christian Coester , Elias Koutsoupias , Philip Lazos

The time-optimal $k$-server problem minimizes the time spent serving all requests instead of the distances traveled. We give a lower bound of $2k-1$ on the competitive ratio of any deterministic online algorithm for this problem, which…

Data Structures and Algorithms · Computer Science 2025-03-10 Fabian Frei , Dennis Komm , Moritz Stocker , Philip Whittington

The generalized k-server problem is a far-reaching extension of the k-server problem with several applications. Here, each server $s_i$ lies in its own metric space $M_i$. A request is a k-tuple $r = (r_1,r_2,\dotsc,r_k)$ and to serve it,…

Data Structures and Algorithms · Computer Science 2017-07-18 Nikhil Bansal , Marek Elias , Grigorios Koumoutsos , Jesper Nederlof

We consider online algorithms for the $k$-server problem on trees of size $n$. Chrobak and Larmore proposed a $k$-competitive algorithm for this problem that has the optimal competitive ratio. However, the existing implementations have…

Data Structures and Algorithms · Computer Science 2024-04-05 Kamil Khadiev , Maxim Yagafarov

We study the $k$-server problem with time-windows. In this problem, each request $i$ arrives at some point $v_i$ of an $n$-point metric space at time $b_i$ and comes with a deadline $e_i$. One of the $k$ servers must be moved to $v_i$ at…

Data Structures and Algorithms · Computer Science 2021-11-18 Anupam Gupta , Amit Kumar , Debmalya Panigrahi

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…

Data Structures and Algorithms · Computer Science 2024-10-29 Sander Borst , Marek Eliáš , Moritz Venzin

Consider the problem: we are given $n$ boxes, labeled $\{1,2,\ldots, n\}$ by an adversary, each containing a single number chosen from an unknown distribution; these $n$ distributions are not necessarily identical. We are also given an…

Data Structures and Algorithms · Computer Science 2024-05-13 Mohammad Taghi Hajiaghayi , Dariusz R. Kowalski , Piotr Krysta , Jan Olkowski

The weighted $k$-server problem is a natural generalization of the $k$-server problem in which the cost incurred in moving a server is the distance traveled times the weight of the server. Even after almost three decades since the seminal…

Data Structures and Algorithms · Computer Science 2021-07-15 Nikhil Ayyadevara , Ashish Chiplunkar

In this paper, we study a stochastic variant of the celebrated k-server problem. In the k-server problem, we are required to minimize the total movement of k servers that are serving an online sequence of t requests in a metric. In the…

Data Structures and Algorithms · Computer Science 2017-06-01 Sina Dehghani , Soheil Ehsani , MohammadTaghi HajiAghayi , Vahid Liaghat , Saeed Seddighin

In this paper, we study the weighted $k$-server problem on the uniform metric in both the offline and online settings. We start with the offline setting. In contrast to the (unweighted) $k$-server problem which has a polynomial-time…

Data Structures and Algorithms · Computer Science 2023-07-25 Anupam Gupta , Amit Kumar , Debmalya Panigrahi

We show how to restrict the analysis of a class of online problems that includes the $k$-server problem in finite metrics such that we only have to consider finite sequences of request. When applying the restrictions, both the optimal…

Data Structures and Algorithms · Computer Science 2013-03-13 Tobias Mömke

We present an $O((\log n)^2)$-competitive algorithm for metrical task systems (MTS) on any $n$-point metric space that is also $1$-competitive for service costs. This matches the competitive ratio achieved by Bubeck, Cohen, Lee, and Lee…

Data Structures and Algorithms · Computer Science 2021-11-23 Farzam Ebrahimnejad , James R. Lee

In a 1989 paper titled "shortest paths without a map", Papadimitriou and Yannakakis introduced an online model of searching in a weighted layered graph for a target node, while attempting to minimize the total length of the path traversed…

Data Structures and Algorithms · Computer Science 2024-12-17 Sébastien Bubeck , Christian Coester , Yuval Rabani

We extend the Mobile Server Problem, introduced in SPAA'17, to a model where k identical mobile resources, here named servers, answer requests appearing at points in the Euclidean space. In order to reduce communication costs, the positions…

Data Structures and Algorithms · Computer Science 2019-07-24 Björn Feldkord , Till Knollmann , Manuel Malatyali , Friedhelm Meyer auf der Heide

In the online metric matching problem, $n$ servers and $n$ requests lie in a metric space. Servers are available upfront, and requests arrive sequentially. An arriving request must be matched immediately and irrevocably to an available…

Data Structures and Algorithms · Computer Science 2026-04-22 Yingxi Li , Ellen Vitercik , Mingwei Yang

We study the problem of metrical service systems with multiple servers (MSSMS), which generalizes two well-known problems -- the $k$-server problem, and metrical service systems. The MSSMS problem is to service requests, each of which is an…

Data Structures and Algorithms · Computer Science 2014-05-22 Ashish Chiplunkar , Sundar Vishwanathan

In this paper, we study the Min-cost Perfect $k$-way Matching with Delays ($k$-MPMD), recently introduced by Melnyk et al. In the problem, $m$ requests arrive one-by-one over time in a metric space. At any time, we can irrevocably make a…

Data Structures and Algorithms · Computer Science 2023-10-30 Naonori Kakimura , Tomohiro Nakayoshi

We initiate a formal study of fairness for the $k$-server problem, where the objective is not only to minimize the total movement cost, but also to distribute the cost equitably among servers. We first define a general notion of…

Data Structures and Algorithms · Computer Science 2025-12-25 Mohammadreza Daneshvaramoli , Helia Karisani , Mohammad Hajiesmaili , Shahin Kamali , Cameron Musco

We consider the task of estimating the entropy of $k$-ary distributions from samples in the streaming model, where space is limited. Our main contribution is an algorithm that requires $O\left(\frac{k \log…

Information Theory · Computer Science 2019-11-20 Jayadev Acharya , Sourbh Bhadane , Piotr Indyk , Ziteng Sun

We study three classical online problems -- $k$-server, $k$-taxi, and chasing size $k$ sets -- through a lens of smoothed analysis. Our setting allows request locations to be adversarial up to small perturbations, interpolating between…

Data Structures and Algorithms · Computer Science 2025-07-25 Christian Coester , Jack Umenberger