Journal of Computer and System Sciences最新文献

{"title":"Bipartite 3-regular counting problems with mixed signs","authors":"Jin-Yi Cai,&nbsp;Austen Z. Fan,&nbsp;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><p>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 <span><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></span>, where <em>f</em> 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 <em>f</em>. The constraint function can take both positive and negative values, allowing for cancellations. In addition, we discover a new phenomenon: there is a set <span><math><mi>F</mi></math></span> with the property that for every <span><math><mi>f</mi><mo>∈</mo><mi>F</mi></math></span> the problem <span><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></span> is planar P-time computable but #P-hard in general, yet its planar tractability is by a <em>combination</em> of a holographic transformation by <span><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></span> to FKT <em>together</em> with an independent global argument.</p></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}

{"title":"On finding separators in temporal split and permutation graphs","authors":"Nicolas Maack ,&nbsp;Hendrik Molter ,&nbsp;Rolf Niedermeier ,&nbsp;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><p>We study the NP-hard <span>Temporal</span> <span><math><mo>(</mo><mi>s</mi><mo>,</mo><mi>z</mi><mo>)</mo></math></span><span>-Separation</span><span> problem on temporal graphs<span>, which are graphs with fixed vertex sets but edge sets that change over discrete time steps. We tackle </span></span><span>Temporal</span> <span><math><mo>(</mo><mi>s</mi><mo>,</mo><mi>z</mi><mo>)</mo></math></span><span>-Separation</span><span> 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 </span><span>Temporal</span> <span><math><mo>(</mo><mi>s</mi><mo>,</mo><mi>z</mi><mo>)</mo></math></span><span>-Separation</span> 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”.</p></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}

{"title":"Restrained medium access control on adversarial shared channels","authors":"Elijah Hradovich ,&nbsp;Marek Klonowski ,&nbsp;Dariusz R. Kowalski","doi":"10.1016/j.jcss.2023.103463","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.103463","url":null,"abstract":"<div><p>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 <em>ρ</em><span> 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 </span><em>k</em> 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 <span><math><mn>1</mn><mo>−</mo><mi>ϵ</mi></math></span> (for any positive <em>ϵ</em>), 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 <span><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></span>. We compare our algorithms experimentally with well-known backoff protocols.</p></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}

{"title":"The possible winner with uncertain weights problem","authors":"Dorothea Baumeister ,&nbsp;Marc Neveling ,&nbsp;Magnus Roos ,&nbsp;Jörg Rothe ,&nbsp;Lena Schend ,&nbsp;Robin Weishaupt ,&nbsp;Lirong Xia","doi":"10.1016/j.jcss.2023.103464","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.103464","url":null,"abstract":"<div><p>The original possible winner problem consists of an unweighted election with partial preferences and a distinguished candidate <em>c</em> and asks whether the preferences can be extended to total ones such that <em>c</em><span> wins the given election. We introduce a novel variant of this problem: possible winner with uncertain weights. In this variant, for a given weighted election, not some of the preferences but some of the preferences' weights are uncertain. We introduce a general framework to study this problem for nonnegative integer and rational weights as well as for four different variations of the problem itself: with and without given upper bounds on the total weight and with and without given ranges to choose weights from. We study the complexity of these problems for important voting systems such as scoring protocols, (simplified) Bucklin and fallback voting, plurality with runoff and veto with runoff, </span><span><math><msup><mrow><mtext>Copeland</mtext></mrow><mrow><mi>α</mi></mrow></msup></math></span>, ranked pairs, and Borda.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"138 ","pages":"Article 103464"},"PeriodicalIF":1.1,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49723479","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}

{"title":"Building squares with optimal state complexity in restricted active self-assembly","authors":"Robert M. Alaniz ,&nbsp;David Caballero ,&nbsp;Sonya C. Cirlos ,&nbsp;Timothy Gomez ,&nbsp;Elise Grizzell ,&nbsp;Andrew Rodriguez ,&nbsp;Robert Schweller ,&nbsp;Armando Tenorio ,&nbsp;Tim Wylie","doi":"10.1016/j.jcss.2023.103462","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.103462","url":null,"abstract":"<div><p><span><span>Tile Automata is a recently defined model of self-assembly that borrows many concepts from </span>cellular automata to create active self-assembling systems where changes may be occurring within an assembly without requiring attachment. This model has been shown to be powerful even with limited assembly size, but many fundamental questions have yet to be explored. Here, we study the state complexity of assembling </span><span><math><mi>n</mi><mo>×</mo><mi>n</mi></math></span> squares in seeded Tile Automata systems where growth starts from a seed and tiles attach one at a time, similar to the abstract Tile Assembly Model. We provide optimal bounds for three classes of seeded Tile Automata systems (all without detachment), which vary in the amount of complexity allowed in the transition rules. We show that, in general, seeded Tile Automata systems require <span><math><mi>Θ</mi><mo>(</mo><msup><mrow><mi>log</mi></mrow><mrow><mfrac><mrow><mn>1</mn></mrow><mrow><mn>4</mn></mrow></mfrac></mrow></msup><mo>⁡</mo><mi>n</mi><mo>)</mo></math></span> states. For single-transition systems, where only one state may change in a transition rule, we show a bound of <span><math><mi>Θ</mi><mo>(</mo><msup><mrow><mi>log</mi></mrow><mrow><mfrac><mrow><mn>1</mn></mrow><mrow><mn>3</mn></mrow></mfrac></mrow></msup><mo>⁡</mo><mi>n</mi><mo>)</mo></math></span>, and for deterministic systems, where each pair of states may only have one associated transition rule, a bound of <span><math><mi>Θ</mi><mo>(</mo><msup><mrow><mo>(</mo><mfrac><mrow><mi>log</mi><mo>⁡</mo><mi>n</mi></mrow><mrow><mi>log</mi><mo>⁡</mo><mi>log</mi><mo>⁡</mo><mi>n</mi></mrow></mfrac><mo>)</mo></mrow><mrow><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></mrow></msup><mo>)</mo></math></span>. Along the way, we provide optimal bounds for the subroutines of building binary strings and building <span><math><mi>O</mi><mo>(</mo><mi>log</mi><mo>⁡</mo><mi>n</mi><mo>)</mo><mo>×</mo><mi>n</mi></math></span> rectangles.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"138 ","pages":"Article 103462"},"PeriodicalIF":1.1,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49737155","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}

{"title":"Deletion to scattered graph classes I - Case of finite number of graph classes","authors":"Ashwin Jacob ,&nbsp;Jari J.H. de Kroon ,&nbsp;Diptapriyo Majumdar ,&nbsp;Venkatesh Raman","doi":"10.1016/j.jcss.2023.05.005","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.05.005","url":null,"abstract":"<div><p>Graph-deletion problems involve deleting a small number of vertices so that the resulting graph belong to a given hereditary graph class. We initiate a study of a natural variation of the problem of deletion to <em>scattered graph classes</em>. We want to delete at most <em>k</em><span> vertices so that each connected component of the resulting graph belongs to one of the constant number of graph classes. As our main result, we show that this problem is non-uniformly fixed-parameter tractable (FPT) when the deletion problem corresponding to each of the constant number of graph classes is known to be FPT and the properties that a graph belongs to these classes are expressible in Counting Monodic Second Order (CMSO) logic. While this is shown using some black box theorems in parameterized complexity, we give a faster FPT algorithm when each of the graph classes has a finite forbidden set.</span></p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"138 ","pages":"Article 103460"},"PeriodicalIF":1.1,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49723543","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}

{"title":"Finding k-secluded trees faster","authors":"Huib Donkers,&nbsp;Bart M.P. Jansen ,&nbsp;Jari J.H. de Kroon","doi":"10.1016/j.jcss.2023.05.006","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.05.006","url":null,"abstract":"<div><p>We revisit the <em>k</em><span>-Secluded Tree</span> problem. Given a vertex-weighted undirected graph <em>G</em>, its objective is to find a maximum-weight induced subtree <em>T</em> whose open neighborhood has size at most <em>k</em>. We present a fixed-parameter tractable algorithm that solves the problem in time <span><math><msup><mrow><mn>2</mn></mrow><mrow><mi>O</mi><mo>(</mo><mi>k</mi><mi>log</mi><mo>⁡</mo><mi>k</mi><mo>)</mo></mrow></msup><mo>⋅</mo><msup><mrow><mi>n</mi></mrow><mrow><mi>O</mi><mo>(</mo><mn>1</mn><mo>)</mo></mrow></msup></math></span>, improving on a double-exponential running time from earlier work by Golovach, Heggernes, Lima, and Montealegre. Starting from a single vertex, our algorithm grows a <em>k</em>-secluded tree by branching on vertices in the open neighborhood of the current tree <em>T</em>. To bound the branching depth, we prove a structural result that can be used to identify a vertex that belongs to the neighborhood of any <em>k</em>-secluded supertree <span><math><msup><mrow><mi>T</mi></mrow><mrow><mo>′</mo></mrow></msup><mo>⊇</mo><mi>T</mi></math></span> once the open neighborhood of <em>T</em> becomes sufficiently large. We extend the algorithm to enumerate compact descriptions of all maximum-weight <em>k</em>-secluded trees, which allows us to count them as well.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"138 ","pages":"Article 103461"},"PeriodicalIF":1.1,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49737158","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}

{"title":"Online bin covering with limited migration","authors":"Sebastian Berndt ,&nbsp;Leah Epstein ,&nbsp;Klaus Jansen ,&nbsp;Asaf Levin ,&nbsp;Marten Maack ,&nbsp;Lars Rohwedder","doi":"10.1016/j.jcss.2023.01.001","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.01.001","url":null,"abstract":"<div><p>Semi-online models where decisions may be revoked in a limited way have been studied extensively in the last years. A well-studied measure of the amount of decisions that can be revoked is the (constant) migration factor. When an object arrives, the decisions for objects of total size at most the migration factor times its size may be revoked. This means that a small object only leads to small changes. We extensively study the bin covering problem with migration in different scenarios. We develop algorithms both for the static case where only insertions are allowed, and for the dynamic case, where items may also depart. We also develop lower bounds for these scenarios both for amortized migration and for worst-case migration showing that our algorithms have nearly optimal migration factor and asymptotic competitive ratio. We therefore resolve the competitiveness of the bin covering problem with migration.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"134 ","pages":"Pages 42-72"},"PeriodicalIF":1.1,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49753162","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}

{"title":"Arithmetical complexity of the language of generic limit sets of cellular automata","authors":"Solène J. Esnay ,&nbsp;Alonso Núñez ,&nbsp;Ilkka Törmä","doi":"10.1016/j.jcss.2023.01.002","DOIUrl":"https://doi.org/10.1016/j.jcss.2023.01.002","url":null,"abstract":"<div><p><span>The generic limit set of a dynamical system<span><span> is the smallest set that attracts most of the space in a topological sense: it is the smallest closed set with a comeager basin of attraction. Introduced by Milnor, it has been studied in the context of one-dimensional </span>cellular automata by Djenaoui and Guillon, Delacourt, and Törmä. In this article we present complexity bounds on realizations of generic limit sets of cellular automata with prescribed properties. We show that generic limit sets have a </span></span><span><math><msubsup><mrow><mi>Π</mi></mrow><mrow><mn>2</mn></mrow><mrow><mn>0</mn></mrow></msubsup></math></span> language if they are inclusion-minimal, a <span><math><msubsup><mrow><mi>Σ</mi></mrow><mrow><mn>1</mn></mrow><mrow><mn>0</mn></mrow></msubsup></math></span> language if the cellular automaton has equicontinuous points, and that these bounds are tight. We also prove that many chain mixing <span><math><msubsup><mrow><mi>Π</mi></mrow><mrow><mn>2</mn></mrow><mrow><mn>0</mn></mrow></msubsup></math></span> subshifts and all chain mixing <span><math><msubsup><mrow><mi>Δ</mi></mrow><mrow><mn>2</mn></mrow><mrow><mn>0</mn></mrow></msubsup></math></span> subshifts are realizable as generic limit sets. As a corollary, we characterize the minimal subshifts that occur as generic limit sets.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"134 ","pages":"Pages 20-41"},"PeriodicalIF":1.1,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49753160","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}

{"title":"On the parameterized complexity of clustering problems for incomplete data","authors":"Eduard Eiben ,&nbsp;Robert Ganian ,&nbsp;Iyad Kanj ,&nbsp;Sebastian Ordyniak ,&nbsp;Stefan Szeider","doi":"10.1016/j.jcss.2022.12.001","DOIUrl":"https://doi.org/10.1016/j.jcss.2022.12.001","url":null,"abstract":"<div><p>We study fundamental clustering problems for incomplete data. Specifically, given a set of incomplete <em>d</em>-dimensional vectors (representing rows of a matrix), the goal is to complete the missing vector entries in a way that admits a partitioning of the vectors into at most <em>k</em> clusters with radius or diameter at most <em>r</em>. We give characterizations of the parameterized complexity of these problems with respect to the parameters <em>k</em>, <em>r</em><span>, and the minimum number of rows and columns needed to cover all the missing entries. We show that the considered problems are fixed-parameter tractable when parameterized by the three parameters combined, and that dropping any of the three parameters results in parameterized intractability. A byproduct of our results is that, for the complete data setting, all problems under consideration are fixed-parameter tractable parameterized by </span><span><math><mi>k</mi><mo>+</mo><mi>r</mi></math></span>.</p></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"134 ","pages":"Pages 1-19"},"PeriodicalIF":1.1,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49737851","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}