Journal of Computer and System Sciences最新文献

An FPT algorithm for timeline cover 时间线覆盖的FPT算法

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-05-22 DOI: 10.1016/j.jcss.2025.103679

Riccardo Dondi , Manuel Lafond

引用次数: 0

Weighted group search on the disk & improved lower bounds for priority evacuation 磁盘上的加权群搜索&改进的优先疏散下界

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-05-15 DOI: 10.1016/j.jcss.2025.103678

Konstantinos Georgiou, Xin Wang

引用次数: 0

Acyclic, star and injective colouring: A complexity picture for H-free graphs 无环、星形和内射着色：无h图的复杂度图

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-05-05 DOI: 10.1016/j.jcss.2025.103662

Jan Bok , Nikola Jedličková , Barnaby Martin , Pascal Ochem , Daniël Paulusma , Siani Smith

引用次数: 0

State complexity of one-way quantum finite automata together with classical states 单向量子有限自动机与经典态的状态复杂性

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-05-02 DOI: 10.1016/j.jcss.2025.103659

Ligang Xiao , Daowen Qiu

{"title":"State complexity of one-way quantum finite automata together with classical states","authors":"Ligang Xiao , Daowen Qiu","doi":"10.1016/j.jcss.2025.103659","DOIUrl":"10.1016/j.jcss.2025.103659","url":null,"abstract":"<div><div>One-way quantum finite automata together with classical states (1QFAC) proposed by Qiu et al. is a new one-way quantum finite automata (1QFA) model that integrates quantum finite automata (QFA) and deterministic finite automata (DFA). The relationshipsand balances between quantum states and classical states in 1QFAC are still not clear. In this paper, we obtain the following results: (1) We optimize the bound given by Qiu et al. that characterizes the relationships between quantum basis states and classical states as well as the equivalent minimal DFA. (2) We give an upper bound showing how many classical states are needed upon reducing the quantum basis states of 1QFAC. (3) We give a lower bound on the classical state number of 1QFAC for recognizing any given regular language, and show that the lower bound is exact if the given language is finite. (4) We show that 1QFAC are exponentially more succinct than DFA and probabilistic finite automata (PFA) for some regular languages. (5) We point out essential relationships between 1QFAC, MO-1QFA and multi-letter 1QFA, and induce a result regarding quantitative relationships between multi-letter 1QFA and DFA.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"154 ","pages":"Article 103659"},"PeriodicalIF":1.1,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916823","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

Compact distributed certification of geometric graph classes 几何图类的紧凑分布证明

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-05-02 DOI: 10.1016/j.jcss.2025.103661

Benjamin Jauregui , Pedro Montealegre , Diego Ramirez-Romero , Ivan Rapaport

{"title":"Compact distributed certification of geometric graph classes","authors":"Benjamin Jauregui , Pedro Montealegre , Diego Ramirez-Romero , Ivan Rapaport","doi":"10.1016/j.jcss.2025.103661","DOIUrl":"10.1016/j.jcss.2025.103661","url":null,"abstract":"<div><div>Distributed proofs allow network nodes to collectively verify if the network satisfies a given predicate. The most versatile mechanism, known as a proof labeling scheme (PLS), functions as the distributed equivalent of NP, where a non-trustable prover assigns each node a certificate. Nodes exchange these certificates with their neighbors to prove the graph satisfies the predicate, with the certificate size being the primary complexity measure. Many graph properties, like planarity or bounded tree-width, can be certified with <span><math><mi>O</mi><mo>(</mo><mi>log</mi><mo>⁡</mo><mi>n</mi><mo>)</mo></math></span>-bit certificates on <em>n</em>-node graphs.</div><div>This paper presents <span><math><mi>O</mi><mo>(</mo><mi>log</mi><mo>⁡</mo><mi>n</mi><mo>)</mo></math></span> distributed certifications for recognizing geometric graph classes commonly found in distributed systems: interval graphs, chordal graphs, circular arc graphs, trapezoid graphs, and permutation graphs. It also establishes tight lower bounds on the certificate sizes required for these geometric intersection graph classes, proving that the proposed certifications are optimal.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"154 ","pages":"Article 103661"},"PeriodicalIF":1.1,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143935544","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

Finding diameter-reducing shortcuts in trees 在树上寻找减少直径的捷径

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-04-23 DOI: 10.1016/j.jcss.2025.103658

Davide Bilò , Luciano Gualà , Stefano Leucci , Luca Pepè Sciarria

{"title":"Finding diameter-reducing shortcuts in trees","authors":"Davide Bilò , Luciano Gualà , Stefano Leucci , Luca Pepè Sciarria","doi":"10.1016/j.jcss.2025.103658","DOIUrl":"10.1016/j.jcss.2025.103658","url":null,"abstract":"<div><div>In the <em>k-Diameter-Optimally Augmenting Tree Problem</em> we are given a tree <em>T</em> of <em>n</em> vertices embedded in an unknown <em>metric</em> space. An oracle can report the cost of any edge in constant time, and we want to augment <em>T</em> with <em>k</em> shortcuts to minimize the resulting diameter. When <span><math><mi>k</mi><mo>=</mo><mn>1</mn></math></span>, <span><math><mi>O</mi><mo>(</mo><mi>n</mi><mi>log</mi><mo>⁡</mo><mi>n</mi><mo>)</mo></math></span>-time algorithms exist for paths and trees. We show that <span><math><mi>o</mi><mo>(</mo><msup><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></math></span> queries cannot provide a better than 10/9-approximation for trees when <span><math><mi>k</mi><mo>≥</mo><mn>3</mn></math></span>. For any constant <span><math><mi>ε</mi><mo>></mo><mn>0</mn></math></span>, we design a linear-time <span><math><mo>(</mo><mn>1</mn><mo>+</mo><mi>ε</mi><mo>)</mo></math></span>-approximation algorithm for paths when <span><math><mi>k</mi><mo>=</mo><mi>o</mi><mo>(</mo><msqrt><mrow><mi>log</mi><mo>⁡</mo><mi>n</mi></mrow></msqrt><mo>)</mo></math></span>, thus establishing a dichotomy between paths and trees for <span><math><mi>k</mi><mo>≥</mo><mn>3</mn></math></span>. Our algorithm employs an ad-hoc data structure, which we also use in a linear-time 4-approximation algorithm for trees, and to compute the diameter of (possibly non-metric) graphs with <span><math><mi>n</mi><mo>+</mo><mi>k</mi><mo>−</mo><mn>1</mn></math></span> edges in time <span><math><mi>O</mi><mo>(</mo><mi>n</mi><mi>k</mi><mi>log</mi><mo>⁡</mo><mi>n</mi><mo>)</mo></math></span>.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"153 ","pages":"Article 103658"},"PeriodicalIF":1.1,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879465","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

Near-optimal dispersion on arbitrary anonymous graphs 任意匿名图上的近最优色散

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-03-22 DOI: 10.1016/j.jcss.2025.103656

Ajay D. Kshemkalyani , Gokarna Sharma

{"title":"Near-optimal dispersion on arbitrary anonymous graphs","authors":"Ajay D. Kshemkalyani , Gokarna Sharma","doi":"10.1016/j.jcss.2025.103656","DOIUrl":"10.1016/j.jcss.2025.103656","url":null,"abstract":"<div><div>Given an undirected, anonymous, port-labeled graph of <em>n</em> memory-less nodes, <em>m</em> edges, and degree Δ, we consider the problem of dispersing <span><math><mi>k</mi><mo>≤</mo><mi>n</mi></math></span> robots (or tokens) positioned initially arbitrarily on the nodes of the graph to exactly <em>k</em> different nodes, one on each node. The objective is to simultaneously minimize time and memory requirement at each robot. The best previously known algorithm solves this problem in <span><math><mi>O</mi><mo>(</mo><mi>min</mi><mo>⁡</mo><mo>{</mo><mi>m</mi><mo>,</mo><mi>k</mi><mi>Δ</mi><mo>}</mo><mo>⋅</mo><mi>log</mi><mo>⁡</mo><mi>ℓ</mi><mo>)</mo></math></span> time storing <span><math><mi>O</mi><mo>(</mo><mi>log</mi><mo>⁡</mo><mo>(</mo><mi>k</mi><mo>+</mo><mi>Δ</mi><mo>)</mo><mo>)</mo></math></span> bits at each robot, where <span><math><mi>ℓ</mi><mo>≤</mo><mi>k</mi><mo>/</mo><mn>2</mn></math></span> is the number of nodes with multiple robots positioned on them in the initial configuration. In this paper, we present a novel multi-source DFS traversal algorithm solving this problem in <span><math><mi>O</mi><mo>(</mo><mi>min</mi><mo>⁡</mo><mo>{</mo><mi>m</mi><mo>,</mo><mi>k</mi><mi>Δ</mi><mo>}</mo><mo>)</mo></math></span> time with <span><math><mi>O</mi><mo>(</mo><mi>log</mi><mo>⁡</mo><mo>(</mo><mi>k</mi><mo>+</mo><mi>Δ</mi><mo>)</mo><mo>)</mo></math></span> bits at each robot. The memory complexity of our algorithm is already asymptotically optimal and the time complexity is asymptotically optimal for the graphs of constant degree <span><math><mi>Δ</mi><mo>=</mo><mi>O</mi><mo>(</mo><mn>1</mn><mo>)</mo></math></span>. The result holds in both synchronous and asynchronous settings.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"152 ","pages":"Article 103656"},"PeriodicalIF":1.1,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Bounding the number of reticulation events for displaying multiple trees in a phylogenetic network 限制在系统发育网络中显示多个树的网状事件的数量

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-03-20 DOI: 10.1016/j.jcss.2025.103657

Yufeng Wu , Louxin Zhang

引用次数: 0

Reconstructing semi-directed level-1 networks using few quarnets 利用少四元重构半有向一级网络

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-03-19 DOI: 10.1016/j.jcss.2025.103655

Martin Frohn , Niels Holtgrefe , Leo van Iersel , Mark Jones , Steven Kelk

{"title":"Reconstructing semi-directed level-1 networks using few quarnets","authors":"Martin Frohn , Niels Holtgrefe , Leo van Iersel , Mark Jones , Steven Kelk","doi":"10.1016/j.jcss.2025.103655","DOIUrl":"10.1016/j.jcss.2025.103655","url":null,"abstract":"<div><div>Semi-directed networks are partially directed graphs that model evolution where the directed edges represent reticulate evolutionary events. We present an algorithm that reconstructs binary <em>n</em>-leaf semi-directed level-1 networks in <span><math><mi>O</mi><mo>(</mo><msup><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></math></span> time from its quarnets (4-leaf subnetworks). Our method assumes we have direct access to all quarnets, yet uses only an asymptotically optimal number of <span><math><mi>O</mi><mo>(</mo><mi>n</mi><mi>log</mi><mo>⁡</mo><mi>n</mi><mo>)</mo></math></span> quarnets. When the network is assumed to contain no triangles, our method instead relies only on four-cycle quarnets and the splits of the other quarnets. A variant of our algorithm works with quartets rather than quarnets and we show that it reconstructs most of a semi-directed level-1 network from an asymptotically optimal <span><math><mi>O</mi><mo>(</mo><mi>n</mi><mi>log</mi><mo>⁡</mo><mi>n</mi><mo>)</mo></math></span> of the quartets it displays. Additionally, we provide an <span><math><mi>O</mi><mo>(</mo><msup><mrow><mi>n</mi></mrow><mrow><mn>3</mn></mrow></msup><mo>)</mo></math></span> time algorithm that reconstructs the tree-of-blobs of any binary <em>n</em>-leaf semi-directed network with unbounded level from <span><math><mi>O</mi><mo>(</mo><msup><mrow><mi>n</mi></mrow><mrow><mn>3</mn></mrow></msup><mo>)</mo></math></span> splits of its quarnets.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"152 ","pages":"Article 103655"},"PeriodicalIF":1.1,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143715791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Instability of backoff protocols with arbitrary arrival rates 任意到达率下退避方案的不稳定性

IF 1.1 3区计算机科学

Journal of Computer and System Sciences Pub Date : 2025-03-04 DOI: 10.1016/j.jcss.2025.103638

Leslie Ann Goldberg, John Lapinskas

引用次数: 0