Journal of Computer and System Sciences最新文献_第8页

Etherless Ethereum tokens: Simulating native tokens in Ethereum 以太坊代币:在以太坊中模拟原生代币

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2023-08-01 DOI: 10.1016/j.jcss.2023.02.001

John Andrews , Michele Ciampi , Vassilis Zikas

引用次数: 0

Parameterized complexity of graph planarity with restricted cyclic orders 受限循环阶图平面性的参数化复杂度

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2023-08-01 DOI: 10.1016/j.jcss.2023.02.007

Giuseppe Liotta , Ignaz Rutter , Alessandra Tappini

{"title":"Parameterized complexity of graph planarity with restricted cyclic orders","authors":"Giuseppe Liotta , Ignaz Rutter , Alessandra Tappini","doi":"10.1016/j.jcss.2023.02.007","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.02.007","url":null,"abstract":"<div>We study the complexity of testing whether a biconnected graph <math><mi>G</mi><mo>=</mo><mo>(</mo><mi>V</mi><mo>,</mo><mi>E</mi><mo>)</mo></math> is planar with the constraint that some cyclic orders of the edges incident to its vertices are allowed while some others are forbidden. The allowed cyclic orders are described by associating every vertex v of G with a set <math><mi>D</mi><mo>(</mo><mi>v</mi><mo>)</mo></math> of FPQ-trees. Let tw be the treewidth of G and let <math><msub><mrow><mi>D</mi></mrow><mrow><mi>max</mi></mrow></msub></math> be the maximum number of FPQ-trees per vertex. We show that the problem is FPT when parameterized by <math><mtext>tw</mtext><mo>+</mo><msub><mrow><mi>D</mi></mrow><mrow><mi>max</mi></mrow></msub></math>, paraNP-hard when parameterized by <math><msub><mrow><mi>D</mi></mrow><mrow><mi>max</mi></mrow></msub></math>, and W[1]-hard when parameterized by tw. We also consider NodeTrix planar representations of clustered graphs, where clusters are adjacency matrices and inter-cluster edges are non-intersecting simple curves. We prove that NodeTrix planarity with fixed sides is FPT when parameterized by the size of clusters plus the treewidth of the graph obtained by collapsing clusters to single vertices, provided that this graph is biconnected.</div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"135 ","pages":"Pages 125-144"},"PeriodicalIF":1.1,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49739733","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

Complexity of word problems for HNN-extensions HNN扩展词问题的复杂性

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2023-08-01 DOI: 10.1016/j.jcss.2023.02.005

Markus Lohrey

引用次数: 0

Bankrupting Sybil despite churn 让西比尔破产，尽管搅拌

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2023-08-01 DOI: 10.1016/j.jcss.2023.02.004

Diksha Gupta , Jared Saia , Maxwell Young

引用次数: 0

How heavy independent sets help to find arborescences with many leaves in DAGs 重独立集如何帮助在dag中找到具有许多叶片的乔木

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2023-08-01 DOI: 10.1016/j.jcss.2023.02.006

Cristina G. Fernandes , Carla N. Lintzmayer

引用次数: 1

On the exact amount of missing information that makes finding possible winners hard 缺失信息的确切数量使得找到可能的赢家变得困难

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2023-08-01 DOI: 10.1016/j.jcss.2023.02.003

Palash Dey , Neeldhara Misra

{"title":"On the exact amount of missing information that makes finding possible winners hard","authors":"Palash Dey , Neeldhara Misra","doi":"10.1016/j.jcss.2023.02.003","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.02.003","url":null,"abstract":"<div>In the possible winner problem, we need to compute if a set of partial votes can be completed such that a given candidate wins the election under some specific voting rule. In this paper, we determine the smallest number of undetermined pairs per partial vote for which the Possible Winner problem is <math><mi>NP</mi></math>-complete. In particular, we find the exact values of t for which the Possible Winner problem transitions to being <math><mi>NP</mi></math>-complete from being in <math><mi>P</mi></math>, where t is the maximum number of undetermined pairs in every vote. We demonstrate tight results for a broad class of scoring rules, Copelandα for every <math><mi>α</mi><mo>∈</mo><mo>[</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>]</mo></math>, maximin, and Bucklin voting rules. A somewhat surprising aspect of our results is that for many of these rules, the Possible Winner problem turns out to be hard even if every vote has at most one undetermined pair of candidates.</div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"135 ","pages":"Pages 32-54"},"PeriodicalIF":1.1,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49739540","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

Parameterised temporal exploration problems 参数化时间探索问题

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2023-08-01 DOI: 10.1016/j.jcss.2023.01.003

Thomas Erlebach , Jakob T. Spooner

引用次数: 0

Bipartite 3-regular counting problems with mixed signs 具有混合符号的二分3-正则计数问题

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2023-08-01 DOI: 10.1016/j.jcss.2023.01.006

Jin-Yi Cai, Austen Z. Fan, Yin Liu

{"title":"Bipartite 3-regular counting problems with mixed signs","authors":"Jin-Yi Cai, Austen Z. Fan, Yin Liu","doi":"10.1016/j.jcss.2023.01.006","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.01.006","url":null,"abstract":"<div>We prove a complexity dichotomy for a class of counting problems expressible as bipartite 3-regular Holant problems. These are also counting CSP problems where every constraint has arity 3 and every variable is read-thrice. For every problem of the form <math><mi>Holant</mi><mspace></mspace><mrow><mo>(</mo><mi>f</mi><mo>|</mo><msub><mrow><mo>=</mo></mrow><mrow><mn>3</mn></mrow></msub><mo>)</mo></mrow></math>, where f is any integer (or equivalently, rational)-valued ternary symmetric constraint function on Boolean variables, we prove that it is either P-time computable or #P-hard, depending on an explicit criterion of f. The constraint function can take both positive and negative values, allowing for cancellations. In addition, we discover a new phenomenon: there is a set <math><mi>F</mi></math> with the property that for every <math><mi>f</mi><mo>∈</mo><mi>F</mi></math> the problem <math><mi>Holant</mi><mspace></mspace><mrow><mo>(</mo><mi>f</mi><mo>|</mo><msub><mrow><mo>=</mo></mrow><mrow><mn>3</mn></mrow></msub><mo>)</mo></mrow></math> is planar P-time computable but #P-hard in general, yet its planar tractability is by a combination of a holographic transformation by <math><mo>[</mo><mtable><mtr><mtd><mn>1</mn></mtd><mtd><mn>1</mn></mtd></mtr><mtr><mtd><mn>1</mn></mtd><mtd><mo>−</mo><mn>1</mn></mtd></mtr></mtable><mo>]</mo></math> to FKT together with an independent global argument.</div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"135 ","pages":"Pages 15-31"},"PeriodicalIF":1.1,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49762896","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

On finding separators in temporal split and permutation graphs 关于在时间分裂图和置换图中寻找分隔符

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2023-08-01 DOI: 10.1016/j.jcss.2023.01.004

Nicolas Maack , Hendrik Molter , Rolf Niedermeier , Malte Renken

{"title":"On finding separators in temporal split and permutation graphs","authors":"Nicolas Maack , Hendrik Molter , Rolf Niedermeier , Malte Renken","doi":"10.1016/j.jcss.2023.01.004","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.01.004","url":null,"abstract":"<div>We study the NP-hard Temporal <math><mo>(</mo><mi>s</mi><mo>,</mo><mi>z</mi><mo>)</mo></math>-Separation problem on temporal graphs, which are graphs with fixed vertex sets but edge sets that change over discrete time steps. We tackle Temporal <math><mo>(</mo><mi>s</mi><mo>,</mo><mi>z</mi><mo>)</mo></math>-Separation by restricting the layers (i.e., graphs characterized by edges that are present at a certain point in time) to specific graph classes. We restrict the layers of the temporal graphs to be either all split graphs or all permutation graphs (both being perfect graph classes) and provide both intractability and tractability results. In particular, we show that in general Temporal <math><mo>(</mo><mi>s</mi><mo>,</mo><mi>z</mi><mo>)</mo></math>-Separation remains NP-hard both on temporal split and temporal permutation graphs, but we also spot promising islands of fixed-parameter tractability particularly based on parameterizations that measure the amount of “change over time”.</div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"135 ","pages":"Pages 1-14"},"PeriodicalIF":1.1,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49762893","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

Restrained medium access control on adversarial shared channels 对抗性共享信道上的受限介质访问控制

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2023-07-07 DOI: 10.1016/j.jcss.2023.103463

Elijah Hradovich , Marek Klonowski , Dariusz R. Kowalski

{"title":"Restrained medium access control on adversarial shared channels","authors":"Elijah Hradovich , Marek Klonowski , Dariusz R. Kowalski","doi":"10.1016/j.jcss.2023.103463","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.103463","url":null,"abstract":"<div>We study the fundamental problem of utilization of the channel shared by stations competing to transmit packets on the channel. In their turn, packets are continuously injected into stations' queues by an adversary at a rate at most ρ packets per round. The aim of the distributed medium access control algorithms is to successfully transmit packets and maintain system stability (bounded queues). We further restrain algorithms by introducing an upper bound k on the allowed number of active stations in any given round. We construct adaptive and full sensing protocols with optimal throughput 1 and almost optimal throughput <math><mn>1</mn><mo>−</mo><mi>ϵ</mi></math> (for any positive ϵ), respectively, in a constant-restrained channel. On the opposite side, we show that restricted protocols based on schedules known in advance suffer from a substantial drop of throughput, at most <math><mi>min</mi><mo>⁡</mo><mo>{</mo><mfrac><mrow><mi>k</mi></mrow><mrow><mi>n</mi></mrow></mfrac><mo>,</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mi>log</mi><mo>⁡</mo><mi>n</mi></mrow></mfrac><mo>}</mo></math>. We compare our algorithms experimentally with well-known backoff protocols.</div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"138 ","pages":"Article 103463"},"PeriodicalIF":1.1,"publicationDate":"2023-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49723748","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