Journal of Computer and System Sciences最新文献_第2页

How to tamper with a Parliament: Strategic campaigns in apportionment elections 如何篡改议会：分配选举中的战略运动

IF 0.9 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-08-08 DOI: 10.1016/j.jcss.2025.103700

Robert Bredereck , Piotr Faliszewski , Michał Furdyna , Andrzej Kaczmarczyk , Joanna Kaczmarek , Martin Lackner , Christian Laußmann , Jörg Rothe , Tessa Seeger

{"title":"How to tamper with a Parliament: Strategic campaigns in apportionment elections","authors":"Robert Bredereck , Piotr Faliszewski , Michał Furdyna , Andrzej Kaczmarczyk , Joanna Kaczmarek , Martin Lackner , Christian Laußmann , Jörg Rothe , Tessa Seeger","doi":"10.1016/j.jcss.2025.103700","DOIUrl":"10.1016/j.jcss.2025.103700","url":null,"abstract":"<div><div>In parliamentary elections, parties compete for a limited, typically fixed number of seats. Most parliaments are assembled using apportionment methods that distribute the seats based on the parties' vote counts. Common apportionment methods include divisor sequence methods (like D'Hondt or Sainte-Laguë), the largest-remainder method, and first-past-the-post. In many countries, an electoral threshold is implemented to prevent very small parties from entering the parliament. Further, several countries have apportionment systems that incorporate multiple districts. We study how computationally hard it is to change the election outcome (i.e., to increase or limit the influence of a distinguished party) by convincing a limited number of voters to change their vote. We refer to these bribery-style attacks as <em>strategic campaigns</em> and study the corresponding problems in terms of their computational (both classical and parameterized) complexity. We also run extensive experiments on real-world election data and study the effectiveness of optimal campaigns, in particular as opposed to using heuristic bribing strategies and with respect to the influence of the threshold and the influence of the number of districts. For apportionment elections with threshold, finally, we propose—as an alternative to the standard top-choice mode—the second-chance mode where voters of parties below the threshold receive a second chance to vote for another party, and we establish computational complexity results also in this setting.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"155 ","pages":"Article 103700"},"PeriodicalIF":0.9,"publicationDate":"2025-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Corrections to “On the data complexity of consistent query answering over graph databases [Journal of Computer and System Sciences 88 (2017) 164–194]” 对“基于图形数据库的一致性查询应答的数据复杂性”的修正[Journal of Computer and System Sciences] 88 (2017) 164-194]

IF 0.9 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-08-05 DOI: 10.1016/j.jcss.2025.103694

Pablo Barceló , Gaëlle Fontaine , Sylvain Salvati , Sophie Tison

引用次数: 0

Triangle evacuation of 2 agents in the wireless model & the power of choosing a starting point 无线模型中2个智能体的三角疏散&起点选择的权力

IF 0.9 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-07-31 DOI: 10.1016/j.jcss.2025.103695

Konstantinos Georgiou , Woojin Jang

引用次数: 0

Online knapsack with removal and recourse 在线背包与移除和追索权

IF 0.9 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-07-30 DOI: 10.1016/j.jcss.2025.103697

Hans-Joachim Böckenhauer , Ralf Klasing , Tobias Mömke , Peter Rossmanith , Moritz Stocker , David Wehner

{"title":"Online knapsack with removal and recourse","authors":"Hans-Joachim Böckenhauer , Ralf Klasing , Tobias Mömke , Peter Rossmanith , Moritz Stocker , David Wehner","doi":"10.1016/j.jcss.2025.103697","DOIUrl":"10.1016/j.jcss.2025.103697","url":null,"abstract":"<div><div>We analyze the competitive ratio of the proportional online knapsack problem with removal and limited recourse. In contrast to the classical online knapsack problem, packed items can be removed and a limited number of removed items can be re-inserted to the knapsack. The variant with removal only was analyzed by Iwama and Taketomi (ICALP, 2002). We show that even a single use of recourse can improve the performance of an algorithm. We give lower bounds for a constant number of <span><math><mi>k</mi><mo>≥</mo><mn>1</mn></math></span> uses of recourse in total, matching upper bounds for <span><math><mn>1</mn><mo>≤</mo><mi>k</mi><mo>≤</mo><mn>3</mn></math></span>, and a general upper bound for any value of <em>k</em>. For a variant where a constant number of <span><math><mi>k</mi><mo>≥</mo><mn>1</mn></math></span> uses of recourse can be used per step, we give tight bounds for all <span><math><mi>k</mi><mo>≥</mo><mn>1</mn></math></span>. We further look at a scenario where an algorithm is informed when the instance ends and give improved upper bounds in both variants for this case.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"155 ","pages":"Article 103697"},"PeriodicalIF":0.9,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144766444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Join and subgraph sampling under degree constraints 度约束下的联接和子图采样

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-07-22 DOI: 10.1016/j.jcss.2025.103693

Ru Wang, Yufei Tao

引用次数: 0

Parameterized approaches to orthogonal compaction 正交压缩的参数化方法

IF 0.9 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-07-21 DOI: 10.1016/j.jcss.2025.103692

Walter Didimo , Siddharth Gupta , Philipp Kindermann , Giuseppe Liotta , Alexander Wolff , Meirav Zehavi

{"title":"Parameterized approaches to orthogonal compaction","authors":"Walter Didimo , Siddharth Gupta , Philipp Kindermann , Giuseppe Liotta , Alexander Wolff , Meirav Zehavi","doi":"10.1016/j.jcss.2025.103692","DOIUrl":"10.1016/j.jcss.2025.103692","url":null,"abstract":"<div><div>Orthogonal graph drawings are used in applications such as UML diagrams, VLSI layout, cable plans, and metro maps. We focus on drawing planar graphs and assume that we are given an <em>orthogonal representation</em> that describes the desired shape, but not the exact coordinates of a drawing. Our aim is to compute an orthogonal drawing on the grid that has the minimum area among all grid drawings that adhere to the given orthogonal representation. This problem is called orthogonal compaction (<span>OC</span>) and is known to be NP-hard, even for orthogonal representations of cycles [Evans et al. 2022]. We investigate the complexity of <span>OC</span> with respect to several parameters. Among others, we show that <span>OC</span> is fixed-parameter tractable with respect to the most natural of these parameters, namely, the number of <em>kitty corners</em> of the orthogonal representation: the presence of pairs of kitty corners in an orthogonal representation makes the <span>OC</span> problem hard. Informally speaking, a pair of kitty corners is a pair of reflex corners of a face that point at each other. Accordingly, the number of kitty corners is the number of corners that are involved in some pair of kitty corners.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"155 ","pages":"Article 103692"},"PeriodicalIF":0.9,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Sequentially swapping tokens: Further on graph classes 顺序交换令牌：进一步介绍图类

IF 0.9 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-07-17 DOI: 10.1016/j.jcss.2025.103691

Hironori Kiya , Yuto Okada , Hirotaka Ono , Yota Otachi

引用次数: 0

On the complexity of rainbow vertex colouring diametral path graphs 关于彩虹顶点对直径路径图着色的复杂性

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-07-03 DOI: 10.1016/j.jcss.2025.103683

Jakob Dyrseth , Paloma T. de Lima

引用次数: 0

Making the interval membership width of temporal graphs connected and bidirectional 使时间图的区间隶属度宽度连通和双向

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-07-03 DOI: 10.1016/j.jcss.2025.103684

Filippos Christodoulou , Pierluigi Crescenzi , Andrea Marino , Ana Silva , Dimitrios M. Thilikos

引用次数: 0

Complexity framework for forbidden subgraphs IV: The Steiner Forest problem 禁止子图的复杂度框架IV：斯坦纳森林问题

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-06-27 DOI: 10.1016/j.jcss.2025.103682

Hans L. Bodlaender , Matthew Johnson , Barnaby Martin , Jelle J. Oostveen , Sukanya Pandey , Daniël Paulusma , Siani Smith , Erik Jan van Leeuwen

{"title":"Complexity framework for forbidden subgraphs IV: The Steiner Forest problem","authors":"Hans L. Bodlaender , Matthew Johnson , Barnaby Martin , Jelle J. Oostveen , Sukanya Pandey , Daniël Paulusma , Siani Smith , Erik Jan van Leeuwen","doi":"10.1016/j.jcss.2025.103682","DOIUrl":"10.1016/j.jcss.2025.103682","url":null,"abstract":"<div><div>We study <span>Steiner Forest</span> on <em>H</em>-subgraph-free graphs, that is, graphs that do not contain some fixed graph <em>H</em> as a (not necessarily induced) subgraph. In contrast to the related <span>Steiner Tree</span> problem, <span>Steiner Forest</span> falls outside a recent framework that completely characterizes the complexity of many problems on <em>H</em>-subgraph-free graphs. Hence, the complexity of <span>Steiner Forest</span> on <em>H</em>-subgraph-free graphs remained open. Our main results are four polynomial-time algorithms for different excluded graphs <em>H</em> that are central to further understand its complexity. We also study the complexity of <span>Steiner Forest</span> for graphs with a small <em>c</em>-deletion set, that is, a small set <em>X</em> of vertices such that each connected component of <span><math><mi>G</mi><mo>−</mo><mi>X</mi></math></span> has size at most <em>c</em>. For this parameter, we give two algorithms that we later employ as subroutines (including a faster algorithm when <span><math><mi>c</mi><mo>=</mo><mn>1</mn></math></span>, that is, the vertex cover number) and exhibit a dichotomy theorem.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"154 ","pages":"Article 103682"},"PeriodicalIF":1.1,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144557500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0