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

Quantum and classical query complexities for determining connectedness of matroids 确定拟阵连通性的量子和经典查询复杂性

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2026-01-07 DOI: 10.1016/j.jcss.2026.103758

Xiaowei Huang , Shiguang Feng , Lvzhou Li

Connectivity is a fundamental structural property of matroids, and has been studied algorithmically over 50 years. In 1974, Cunningham proposed a deterministic algorithm consuming

O (n^{2})

queries to the independence oracle to determine whether a matroid is connected. Since then, no algorithm, not even a random one, has worked better. To the best of our knowledge, the classical query complexity lower bound and the quantum complexity for this problem have not been considered. Thus, in this paper we are devoted to addressing these issues, and our contributions are threefold as follows: (i) First, we prove that the randomized query complexity of determining whether a matroid is connected is

Ω (n^{2})

and thus the algorithm proposed by Cunningham is optimal in classical computing. (ii) Second, we present a quantum algorithm with

O (n^{3 / 2})

queries, which exhibits provable quantum speedups over classical ones. (iii) Third, we prove that any quantum algorithm requires

Ω (n)

queries, which indicates that quantum algorithms can achieve at most a quadratic speedup over classical ones. Therefore, we have a relatively comprehensive understanding of the potential of quantum computing in determining the connectedness of matroids.

连通性是拟阵的基本结构性质，已经被算法研究了50多年。1974年，Cunningham提出了一种确定性算法，该算法需要对独立oracle进行O（n2）次查询来确定一个矩阵是否连通。从那时起，没有任何一种算法，甚至是随机算法，比它更有效。据我们所知，该问题的经典查询复杂度下界和量子复杂度尚未被考虑。因此，在本文中，我们致力于解决这些问题，我们的贡献如下：(i)首先，我们证明了确定一个矩阵是否连通的随机查询复杂度为Ω（n2），因此Cunningham提出的算法在经典计算中是最优的。（ii）其次，我们提出了一个具有O（n3/2）个查询的量子算法，它比经典算法具有可证明的量子加速。（iii）第三，我们证明了任何量子算法都需要Ω(n)次查询，这表明量子算法最多可以达到经典算法的二次加速。因此，我们对量子计算在确定拟阵连通性方面的潜力有了相对全面的了解。

{"title":"Quantum and classical query complexities for determining connectedness of matroids","authors":"Xiaowei Huang , Shiguang Feng , Lvzhou Li","doi":"10.1016/j.jcss.2026.103758","DOIUrl":"10.1016/j.jcss.2026.103758","url":null,"abstract":"<div><div>Connectivity is a fundamental structural property of matroids, and has been studied algorithmically over 50 years. In 1974, Cunningham proposed a deterministic algorithm consuming <math><mi>O</mi><mo>(</mo><msup><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></math> queries to the independence oracle to determine whether a matroid is connected. Since then, no algorithm, not even a random one, has worked better. To the best of our knowledge, the classical query complexity lower bound and the quantum complexity for this problem have not been considered. Thus, in this paper we are devoted to addressing these issues, and our contributions are threefold as follows: (i) First, we prove that the randomized query complexity of determining whether a matroid is connected is <math><mi>Ω</mi><mo>(</mo><msup><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></math> and thus the algorithm proposed by Cunningham is optimal in classical computing. (ii) Second, we present a quantum algorithm with <math><mi>O</mi><mo>(</mo><msup><mrow><mi>n</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>2</mn></mrow></msup><mo>)</mo></math> queries, which exhibits provable quantum speedups over classical ones. (iii) Third, we prove that any quantum algorithm requires <math><mi>Ω</mi><mo>(</mo><mi>n</mi><mo>)</mo></math> queries, which indicates that quantum algorithms can achieve at most a quadratic speedup over classical ones. Therefore, we have a relatively comprehensive understanding of the potential of quantum computing in determining the connectedness of matroids.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103758"},"PeriodicalIF":0.9,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976511","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 the structure of Hamiltonian graphs with small independence number 小独立数哈密顿图的结构

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2026-01-05 DOI: 10.1016/j.jcss.2025.103754

Nikola Jedličková , Jan Kratochvíl

A Hamiltonian path (cycle) in a graph is a path (cycle, respectively) which passes through all of its vertices exactly once. The problems of deciding the existence of a Hamiltonian path and a Hamiltonian cycle in an input graph (called Hamiltonian Path resp. Hamiltonian Cycle) is well known to be NP-complete, and restricted classes of graphs which allow for their polynomial-time solutions are intensively investigated. Until very recently, the complexity was open even for graphs of independence number at most 3. Fomin, Golovach, Sagunov, and Simonov [arxiv 2024] showed that for every integer k, Hamiltonian Path and Hamiltonian Cycle are polynomial-time solvable in graphs of independence number bounded by k, and moreover, that these problems are in FPT when parameterized by the independence number of the input graph. As a companion structural result to these general algorithms, we determine explicit obstacles to the existence of a Hamiltonian path for small values of k, namely for graphs of independence number 2, 3, and 4. Identifying these obstacles in an input graph yields alternative polynomial-time algorithms for Hamiltonian Path and Hamiltonian Cycle with no large hidden multiplicative constants.

图中的哈密顿路径（循环）是经过所有顶点一次的路径（循环）。确定输入图中哈密顿路径和哈密顿循环是否存在的问题（称为哈密顿路径问题）。哈密顿循环)众所周知是np完全的，并且对允许其多项式时间解的图的限制类进行了深入的研究。直到最近，即使独立数最多为3的图的复杂性也是开放的。Fomin, Golovach, Sagunov， and Simonov [arxiv 2024]证明了对于每一个整数k， hamilton Path和hamilton Cycle在以k为界的独立数的图中都是多项式时间可解的，并且当用输入图的独立数参数化时，这些问题在FPT中。作为这些一般算法的伴随结构结果，我们确定了小k值的哈密顿路径存在的显式障碍，即独立数为2、3和4的图。在输入图中识别这些障碍，可以产生哈密顿路径和哈密顿循环的替代多项式时间算法，没有大的隐藏乘法常数。

{"title":"On the structure of Hamiltonian graphs with small independence number","authors":"Nikola Jedličková , Jan Kratochvíl","doi":"10.1016/j.jcss.2025.103754","DOIUrl":"10.1016/j.jcss.2025.103754","url":null,"abstract":"<div><div>A Hamiltonian path (cycle) in a graph is a path (cycle, respectively) which passes through all of its vertices exactly once. The problems of deciding the existence of a Hamiltonian path and a Hamiltonian cycle in an input graph (called Hamiltonian Path resp. Hamiltonian Cycle) is well known to be NP-complete, and restricted classes of graphs which allow for their polynomial-time solutions are intensively investigated. Until very recently, the complexity was open even for graphs of independence number at most 3. Fomin, Golovach, Sagunov, and Simonov [arxiv 2024] showed that for every integer k, Hamiltonian Path and Hamiltonian Cycle are polynomial-time solvable in graphs of independence number bounded by k, and moreover, that these problems are in FPT when parameterized by the independence number of the input graph. As a companion structural result to these general algorithms, we determine explicit obstacles to the existence of a Hamiltonian path for small values of k, namely for graphs of independence number 2, 3, and 4. Identifying these obstacles in an input graph yields alternative polynomial-time algorithms for Hamiltonian Path and Hamiltonian Cycle with no large hidden multiplicative constants.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103754"},"PeriodicalIF":0.9,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976510","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

Routing few robots in a crowded network 在拥挤的网络中路由几个机器人

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2026-01-02 DOI: 10.1016/j.jcss.2025.103753

Argyrios Deligkas , Eduard Eiben , Robert Ganian , Iyad Kanj , Dominik Leko , M.S. Ramanujan

In Graph Coordinated Motion Planning, we are given a graph G some of whose vertices are occupied by robots, and we are asked to route k marked robots to their destinations while avoiding collisions and without exceeding a given budget ℓ on the number of robot moves. We continue the recent investigation of the problem [ICALP 2024], focusing on the parameter k that captures the task of routing a small number of robots in a possibly crowded graph. We prove that the problem is W[1]-hard parameterized by ℓ even for

k = 1

, but fixed-parameter tractable parameterized by k plus the treedepth of G. We complement the latter algorithm with an NP-hardness reduction which shows that both parameters are necessary to achieve tractability.

在图协调运动规划中，我们给出一个图G，其中一些顶点被机器人占据，我们被要求将k个标记的机器人路由到目的地，同时避免碰撞，并且不超过机器人移动次数的给定预算。我们继续最近对这个问题的调查[ICALP 2024]，重点关注参数k，它捕获了在可能拥挤的图中路由少量机器人的任务。我们证明了即使对于k=1，问题是W[1]-hard参数化的，但问题是固定参数可处理的，参数化是k加上树深g。我们用np -硬度约简来补充后一种算法，这表明两个参数都是实现可处理性所必需的。

引用次数: 0

The Normal Domination Game in graphs 正常统治游戏的图表

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2025-12-17 DOI: 10.1016/j.jcss.2025.103751

João Marcos Brito , Thiago Marcilon , Nicolas A. Martins , Rudini Sampaio

In 2010, Brešar, Klavžar and Rall introduced the optimization variant of the graph domination game and the game domination number. This variant has been extensively investigated in the literature, with several papers published on this topic. Interestingly, the most common variant of combinatorial games, the normal variant, in which the last to play wins, had never been investigated for the graph domination game. In this paper, we start the study of the normal play of the domination game, which we call Normal Domination Game. We first prove that this game is PSPACE-complete even in graphs with diameter two. We also use the Sprague-Grundy theory to prove that Alice (the first player) wins in the path

P_{n}

if and only if n is not a multiple of 4, and wins in the cycle

C_{n}

if and only if

n = 4 k + 3

for some integer k. Moreover, we obtain a polynomial time algorithm to decide the winner for any disjoint union of paths and cycles in the Normal Domination Game and its natural partizan variant. Finally, we also prove that the Misère Domination Game (the last to play loses) is PSPACE-complete, as are the natural partizan variants of the normal game and the misère game.

2010年Brešar、Klavžar和Rall引入了图形统治游戏的优化变体和游戏统治数。这种变体在文献中被广泛研究，有几篇论文发表在这个主题上。有趣的是，组合游戏最常见的变体，即最后一个玩家获胜的正常变体，从未被用于图形控制游戏的研究。本文开始研究统治博弈的正常博弈，我们称之为正常统治博弈。我们首先证明了这个对策即使在直径为2的图上也是pspace完全的。我们还使用Sprague-Grundy理论证明了Alice（第一个玩家）当且仅当n不是4的倍数时在路径Pn中获胜，并且当且仅当n=4k+3时在某个整数k中在循环Cn中获胜。此外，我们获得了一个多项式时间算法来确定正常统治博弈及其自然党派变种中任何路径和循环的不交并的赢家。最后，我们还证明了mis统治游戏（最后玩的人输）是pspace完全的，就像正常游戏和mis游戏的自然游击变体一样。

{"title":"The Normal Domination Game in graphs","authors":"João Marcos Brito , Thiago Marcilon , Nicolas A. Martins , Rudini Sampaio","doi":"10.1016/j.jcss.2025.103751","DOIUrl":"10.1016/j.jcss.2025.103751","url":null,"abstract":"<div><div>In 2010, Brešar, Klavžar and Rall introduced the optimization variant of the graph domination game and the game domination number. This variant has been extensively investigated in the literature, with several papers published on this topic. Interestingly, the most common variant of combinatorial games, the normal variant, in which the last to play wins, had never been investigated for the graph domination game. In this paper, we start the study of the normal play of the domination game, which we call Normal Domination Game. We first prove that this game is PSPACE-complete even in graphs with diameter two. We also use the Sprague-Grundy theory to prove that Alice (the first player) wins in the path <math><msub><mrow><mi>P</mi></mrow><mrow><mi>n</mi></mrow></msub></math> if and only if n is not a multiple of 4, and wins in the cycle <math><msub><mrow><mi>C</mi></mrow><mrow><mi>n</mi></mrow></msub></math> if and only if <math><mi>n</mi><mo>=</mo><mn>4</mn><mi>k</mi><mo>+</mo><mn>3</mn></math> for some integer k. Moreover, we obtain a polynomial time algorithm to decide the winner for any disjoint union of paths and cycles in the Normal Domination Game and its natural partizan variant. Finally, we also prove that the Misère Domination Game (the last to play loses) is PSPACE-complete, as are the natural partizan variants of the normal game and the misère game.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103751"},"PeriodicalIF":0.9,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839598","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

Approximation algorithms for two extensions of min-k-union 两种min-k-并扩展的逼近算法

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2025-12-16 DOI: 10.1016/j.jcss.2025.103750

Hua Chen , Lin Chen , Shenghao Ye , Guochuan Zhang

In the min-k-union problem (MkU), given a ground set N, a collection

S

of m subsets of N, and an integer k, one needs to select k sets from

S

so that their union has the smallest size. In this paper, we study two extensions of MkU.

The first is the maximum coverage interdiction problem, where there is a leader with cardinality

k_{l}

and a follower with cardinality

k_{f}

. The leader's goal (as well as the problem) is to remove up to

k_{l}

sets from

S

so that the union size of the at most

k_{f}

sets selected by the follower from the remaining sets attains the minimum. We provide an

\tilde{O} (\sqrt{m})

-approximation algorithm, while a lower bound of

Ω (m^{1 / 4})

under the “Dense versus Random” conjecture for MkU [Chlamtáč et al. '17] applies to our problem as well. When

k_{l} = m - k_{f}

, this problem becomes MkU.

The second problem deals with monotone submodular minimization with a cardinality constraint. Given a ground set N of n elements, a nonnegative monotone submodular function f, and an integer k, we are required to find a size-k set

S \subseteq N

that minimizes

f (S)

. We propose a 2

\sqrt{n}

-approximation algorithm, matching (up to a logarithmic factor) the lower bound of

Ω (\sqrt{\frac{n}{\ln n}})

[Svitkina and Fleischer '11]. When f is a coverage function, this problem becomes MkU.

在min-k-并问题（MkU）中，给定一个基集N，一个由N的m个子集组成的集合S，以及一个整数k，需要从S中选择k个集合，使它们的并集具有最小的大小。本文研究了MkU的两个扩展。第一个是最大覆盖拦截问题，其中有一个基数为kl的领导者和一个基数为kf的追随者。领导者的目标（和问题一样）是从S中移除最多kl个集合，使追随者从剩余集合中选择的最多kf个集合的并集大小达到最小。我们提供了一个O ~ (m)-近似算法，而MkU在“密集与随机”猜想下的下界Ω（m1/4） [Chlamtáč等人]。[17]也适用于我们的问题。当kl=m−kf时，这个问题变成了MkU。第二个问题处理带有基数约束的单调次模最小化问题。给定一个有N个元素的基集N、一个非负单调子模函数f和一个整数k，求一个大小为k的集S≥f(S)。我们提出了一个2n近似算法，匹配（直到一个对数因子）Ω（nln ln n）的下界[Svitkina和Fleischer '11]。当f是一个覆盖函数时，这个问题就变成了MkU。

{"title":"Approximation algorithms for two extensions of min-k-union","authors":"Hua Chen , Lin Chen , Shenghao Ye , Guochuan Zhang","doi":"10.1016/j.jcss.2025.103750","DOIUrl":"10.1016/j.jcss.2025.103750","url":null,"abstract":"<div><div>In the min-k-union problem (MkU), given a ground set N, a collection <math><mi>S</mi></math> of m subsets of N, and an integer k, one needs to select k sets from <math><mi>S</mi></math> so that their union has the smallest size. In this paper, we study two extensions of MkU.</div><div>The first is the maximum coverage interdiction problem, where there is a leader with cardinality <math><msub><mrow><mi>k</mi></mrow><mrow><mi>l</mi></mrow></msub></math> and a follower with cardinality <math><msub><mrow><mi>k</mi></mrow><mrow><mi>f</mi></mrow></msub></math>. The leader's goal (as well as the problem) is to remove up to <math><msub><mrow><mi>k</mi></mrow><mrow><mi>l</mi></mrow></msub></math> sets from <math><mi>S</mi></math> so that the union size of the at most <math><msub><mrow><mi>k</mi></mrow><mrow><mi>f</mi></mrow></msub></math> sets selected by the follower from the remaining sets attains the minimum. We provide an <math><mover><mrow><mi>O</mi></mrow><mrow><mo>˜</mo></mrow></mover><mo>(</mo><msqrt><mrow><mi>m</mi></mrow></msqrt><mo>)</mo></math>-approximation algorithm, while a lower bound of <math><mi>Ω</mi><mo>(</mo><msup><mrow><mi>m</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>4</mn></mrow></msup><mo>)</mo></math> under the “Dense versus Random” conjecture for MkU [Chlamtáč et al. '17] applies to our problem as well. When <math><msub><mrow><mi>k</mi></mrow><mrow><mi>l</mi></mrow></msub><mo>=</mo><mi>m</mi><mo>−</mo><msub><mrow><mi>k</mi></mrow><mrow><mi>f</mi></mrow></msub></math>, this problem becomes MkU.</div><div>The second problem deals with monotone submodular minimization with a cardinality constraint. Given a ground set N of n elements, a nonnegative monotone submodular function f, and an integer k, we are required to find a size-k set <math><mi>S</mi><mo>⊆</mo><mi>N</mi></math> that minimizes <math><mi>f</mi><mo>(</mo><mi>S</mi><mo>)</mo></math>. We propose a 2<math><msqrt><mrow><mi>n</mi></mrow></msqrt></math>-approximation algorithm, matching (up to a logarithmic factor) the lower bound of <math><mi>Ω</mi><mo>(</mo><msqrt><mrow><mfrac><mrow><mi>n</mi></mrow><mrow><mi>ln</mi><mo>⁡</mo><mi>n</mi></mrow></mfrac></mrow></msqrt><mo>)</mo></math> [Svitkina and Fleischer '11]. When f is a coverage function, this problem becomes MkU.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103750"},"PeriodicalIF":0.9,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839599","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 the parameterized complexity of computing good edge-labelings 计算好的边缘标记的参数化复杂度

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2025-12-16 DOI: 10.1016/j.jcss.2025.103752

Davi de Andrade , Júlio Araújo , Laure Morelle , Ignasi Sau , Ana Silva

A good edge-labeling (gel for short) of a graph G is a function

λ : E (G) \to R

such that, for any ordered pair of vertices

(x, y)

of G, there do not exist two distinct increasing paths from x to y, where “increasing” means that the sequence of labels is non-decreasing. This notion was introduced by Bermond et al. (2013) [3] motivated by practical applications arising from routing and wavelength assignment problems in optical networks. Prompted by the lack of algorithmic results about the problem of deciding whether an input graph admits a gel, called GEL, we initiate its study from the viewpoint of parameterized complexity. We first introduce the natural version of GEL where one wants to use at most c distinct labels, which we call c-GEL, and we prove that it is NP-complete for every

c \geq 2

on very restricted instances. We then provide several positive results, starting with simple polynomial kernels for GEL and c-GEL parameterized by neighborhood diversity or vertex cover. As one of our main technical contributions, we present an FPT algorithm for GEL parameterized by the size of a modulator to a forest of stars, based on a novel approach via a 2-SAT formulation which we believe to be of independent interest. We also present FPT algorithms based on dynamic programming for c-GEL parameterized by treewidth and c, and for GEL parameterized by treewidth and the maximum degree. Finally, we answer positively a question of Bermond et al. (2013) [3] by proving the NP-completeness of a problem strongly related to GEL, namely that of deciding whether an input graph admits a so-called UPP-orientation.

图G的一个好的边标记（简称凝胶）是一个函数λ:E(G)→R，使得对于G的任意有序顶点对（x,y），不存在从x到y的两个不同的递增路径，其中“递增”意味着标记序列是非递减的。这一概念是由Bermond等人（2013）[3]提出的，其动机是光网络中路由和波长分配问题引起的实际应用。由于缺乏关于判断输入图是否存在凝胶（gel）问题的算法结果，我们从参数化复杂性的角度开始对其进行研究。我们首先引入了自然版本的GEL，其中人们希望使用最多c个不同的标签，我们称之为c-GEL，并且我们证明了在非常有限的情况下，对于每个c≥2，它是np完全的。然后，我们提供了几个积极的结果，从GEL和c-GEL的简单多项式核开始，通过邻域多样性或顶点覆盖参数化。作为我们的主要技术贡献之一，我们提出了一种基于2-SAT公式的新方法的GEL FPT算法，该算法由调制器的大小参数化到恒星森林，我们认为这是一个独立的兴趣。针对以树宽和c为参数的c-GEL，以及以树宽和最大度为参数的GEL，提出了基于动态规划的FPT算法。最后，我们通过证明与GEL强相关的问题的np完备性，即决定输入图是否允许所谓的upp取向，积极回答了Bermond等人（2013）[3]的问题。

{"title":"On the parameterized complexity of computing good edge-labelings","authors":"Davi de Andrade , Júlio Araújo , Laure Morelle , Ignasi Sau , Ana Silva","doi":"10.1016/j.jcss.2025.103752","DOIUrl":"10.1016/j.jcss.2025.103752","url":null,"abstract":"<div><div>A good edge-labeling (gel for short) of a graph G is a function <math><mi>λ</mi><mo>:</mo><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>→</mo><mi>R</mi></math> such that, for any ordered pair of vertices <math><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>)</mo></math> of G, there do not exist two distinct increasing paths from x to y, where “increasing” means that the sequence of labels is non-decreasing. This notion was introduced by Bermond et al. (2013) [3] motivated by practical applications arising from routing and wavelength assignment problems in optical networks. Prompted by the lack of algorithmic results about the problem of deciding whether an input graph admits a gel, called GEL, we initiate its study from the viewpoint of parameterized complexity. We first introduce the natural version of GEL where one wants to use at most c distinct labels, which we call c-GEL, and we prove that it is NP-complete for every <math><mi>c</mi><mo>≥</mo><mn>2</mn></math> on very restricted instances. We then provide several positive results, starting with simple polynomial kernels for GEL and c-GEL parameterized by neighborhood diversity or vertex cover. As one of our main technical contributions, we present an FPT algorithm for GEL parameterized by the size of a modulator to a forest of stars, based on a novel approach via a 2-SAT formulation which we believe to be of independent interest. We also present FPT algorithms based on dynamic programming for c-GEL parameterized by treewidth and c, and for GEL parameterized by treewidth and the maximum degree. Finally, we answer positively a question of Bermond et al. (2013) [3] by proving the NP-completeness of a problem strongly related to GEL, namely that of deciding whether an input graph admits a so-called UPP-orientation.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103752"},"PeriodicalIF":0.9,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789683","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

AdapBlinker: Robust adaptive median filter approach to detect subtle eye blinks AdapBlinker：鲁棒自适应中值滤波方法检测细微眨眼

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2025-12-11 DOI: 10.1016/j.jcss.2025.103746

Hafsa Sidaq , Lei Wang , Jiancheng Chi , Hussain Haider

Nowadays, eye blink detection is gaining significant attention in human-computer interaction systems. Users are increasingly favoring interactions with their phones and computers through non-manual methods, underscoring the constraints of conventional touch interfaces. Wearable technology, such as electrooculography (EOG)-based approaches and infrared sensors (IR), can accurately detect eye blinks; nevertheless, they can be inconvenient after prolonged use. Despite this, the drawbacks of camera-based eye blink recognition techniques are blind spots and the lighting effect. Thus, this study proposes an acoustic signal-based eye blink detection system to overcome these constraints. Acoustic signals can perform fine-grained detection within localized range due to their high attenuation in the air medium. The main benefit of acoustic sensing over conventional methods is that it senses signals directly, so the user does not need to wear any sensors. The prevalence of speakers and microphones in devices is another advancement that supports acoustic sensing. In this research, we present AdapBlinker, which employs the HP ProBook 440 G5 laptop to generate acoustic signals, retrieve data, process acquired signals, and plot Fast Fourier transform (FFT) to extract eye blink signals. AdapBlinker uses an adaptive median filter that adapts to surroundings, eliminates intrusions, and detects subtle blinks. We tested AdapBlinker with thirty-four participants across three settings for five months, achieving an average eye blink detection accuracy of 97.2%.

目前，眨眼检测在人机交互系统中受到越来越多的关注。用户越来越喜欢通过非手动方式与手机和电脑进行交互，这凸显了传统触摸界面的局限性。可穿戴技术，如基于眼电图（EOG）的方法和红外传感器（IR），可以准确地检测眨眼；然而，长时间使用可能会带来不便。尽管如此，基于摄像头的眨眼识别技术的缺点是盲点和灯光效果。因此，本研究提出了一种基于声信号的眨眼检测系统来克服这些限制。由于声信号在空气介质中的高衰减，可以在局部范围内进行细粒度检测。与传统方法相比，声传感的主要优点是它直接感知信号，因此用户不需要佩戴任何传感器。扬声器和麦克风在设备中的普及是支持声传感的另一个进步。在这项研究中，我们提出了AdapBlinker，它使用HP ProBook 440 G5笔记本电脑来产生声信号，检索数据，处理采集的信号，并绘制快速傅里叶变换（FFT）来提取眨眼信号。AdapBlinker使用自适应中值滤波器来适应周围环境，消除干扰，并检测细微的眨眼。我们对34名参与者进行了为期5个月的三种设置测试，达到了97.2%的平均眨眼检测准确率。

{"title":"AdapBlinker: Robust adaptive median filter approach to detect subtle eye blinks","authors":"Hafsa Sidaq , Lei Wang , Jiancheng Chi , Hussain Haider","doi":"10.1016/j.jcss.2025.103746","DOIUrl":"10.1016/j.jcss.2025.103746","url":null,"abstract":"<div><div>Nowadays, eye blink detection is gaining significant attention in human-computer interaction systems. Users are increasingly favoring interactions with their phones and computers through non-manual methods, underscoring the constraints of conventional touch interfaces. Wearable technology, such as electrooculography (EOG)-based approaches and infrared sensors (IR), can accurately detect eye blinks; nevertheless, they can be inconvenient after prolonged use. Despite this, the drawbacks of camera-based eye blink recognition techniques are blind spots and the lighting effect. Thus, this study proposes an acoustic signal-based eye blink detection system to overcome these constraints. Acoustic signals can perform fine-grained detection within localized range due to their high attenuation in the air medium. The main benefit of acoustic sensing over conventional methods is that it senses signals directly, so the user does not need to wear any sensors. The prevalence of speakers and microphones in devices is another advancement that supports acoustic sensing. In this research, we present AdapBlinker, which employs the HP ProBook 440 G5 laptop to generate acoustic signals, retrieve data, process acquired signals, and plot Fast Fourier transform (FFT) to extract eye blink signals. AdapBlinker uses an adaptive median filter that adapts to surroundings, eliminates intrusions, and detects subtle blinks. We tested AdapBlinker with thirty-four participants across three settings for five months, achieving an average eye blink detection accuracy of 97.2%.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103746"},"PeriodicalIF":0.9,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145924260","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 solution discovery via reconfiguration 通过重新配置发现解决方案

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2025-12-11 DOI: 10.1016/j.jcss.2025.103747

Michael R. Fellows , Mario Grobler , Nicole Megow , Amer E. Mouawad , Vijayaragunathan Ramamoorthi , Frances A. Rosamond , Daniel Schmand , Sebastian Siebertz

The dynamics of real-world applications and systems require efficient methods for improving infeasible solutions or restoring corrupted ones by making modifications to the current state of a system in a restricted way. We propose a new framework of solution discovery via reconfiguration for constructing a feasible solution for a given problem by executing a sequence of small modifications starting from a given state or configuration. Our framework integrates and formalizes different aspects of classical local search, reoptimization, and combinatorial reconfiguration. We exemplify our framework on a multitude of fundamental combinatorial problems, namely Vertex Cover, Independent Set, Dominating Set, and Coloring. We study the classical as well as the parameterized complexity of the solution discovery variants of those problems and explore the boundary between tractable and intractable instances.

现实世界应用程序和系统的动态需要有效的方法来改进不可行的解决方案或通过以有限的方式修改系统的当前状态来恢复损坏的解决方案。我们提出了一个新的解决方案发现框架，该框架通过从给定状态或配置开始执行一系列小修改来构造给定问题的可行解决方案。我们的框架集成并形式化了经典局部搜索、再优化和组合重构的不同方面。我们在许多基本的组合问题上举例说明我们的框架，即顶点覆盖、独立集、支配集和着色。我们研究了这些问题的解发现变体的经典复杂度和参数化复杂度，并探索了易处理和难处理实例之间的边界。

引用次数: 0

A divide and conquer algorithm for deciding group cellular automata dynamics 决定群体元胞自动机动态的分治算法

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2025-12-09 DOI: 10.1016/j.jcss.2025.103749

Niccolò Castronuovo , Alberto Dennunzio , Luciano Margara

We prove that many dynamical properties of group cellular automata (GCA) can be decided by decomposing them into a set of much simpler GCA, provided those properties are decidable for such simpler GCA. Specifically, we provide a novel algorithmic technique that decomposes the GCA under investigation into a finite number of GCA, some defined on abelian groups, while others, if any, on products of simple non-abelian isomorphic groups. Importantly, the groups resulting from the decomposition depend only on the original group and are therefore completely independent of both the automaton and the considered property. Consequently, they do not inherit any aspect of the complexity of the automaton under investigation. We study the inheritance of the dynamical properties in the original GCA versus the same properties in the GCA obtained through decomposition. The latter turn out to be significantly easier to analyze than in the original GCA. Then, we show that injectivity, surjectivity, and equicontinuity/sensitivity to initial conditions can be decided by testing them in the smaller GCA produced by the decomposition. Moreover, we prove that the topological entropy of a GCA can be computed, provided one knows how to compute it for GCA defined on products of simple non-abelian isomorphic groups – for which we explicitly prove how to compute it in the surjective case – and on abelian groups. Finally, we prove that no strongly transitive, and therefore no positively expansive, GCA defined on non-abelian groups exist.

我们证明了群元胞自动机（GCA）的许多动力学性质可以通过分解成一组更简单的GCA来确定，只要这些性质对于这种更简单的GCA是可确定的。具体来说，我们提供了一种新的算法技术，将所研究的GCA分解为有限数量的GCA，其中一些定义在阿贝尔群上，而另一些（如果有的话）定义在简单非阿贝尔同构群的乘积上。重要的是，分解产生的组仅依赖于原始组，因此完全独立于自动机和考虑的属性。因此，它们不继承所研究的自动机复杂性的任何方面。我们研究了原始GCA中动态特性的继承性与通过分解得到的GCA中相同特性的继承性。后者比原来的GCA更容易分析。然后，我们证明了注入性、满射性和对初始条件的等连续性/灵敏度可以通过在分解产生的较小GCA中测试来确定。此外，我们证明了一个GCA的拓扑熵是可以计算的，只要我们知道如何计算定义在简单非阿贝尔同构群的乘积上的GCA（我们明确地证明了如何在满射情况下计算它）和阿贝尔群上的GCA。最后，我们证明了在非阿贝尔群上不存在强传递因而不存在正可扩张的GCA。

{"title":"A divide and conquer algorithm for deciding group cellular automata dynamics","authors":"Niccolò Castronuovo , Alberto Dennunzio , Luciano Margara","doi":"10.1016/j.jcss.2025.103749","DOIUrl":"10.1016/j.jcss.2025.103749","url":null,"abstract":"<div><div>We prove that many dynamical properties of group cellular automata (GCA) can be decided by decomposing them into a set of much simpler GCA, provided those properties are decidable for such simpler GCA. Specifically, we provide a novel algorithmic technique that decomposes the GCA under investigation into a finite number of GCA, some defined on abelian groups, while others, if any, on products of simple non-abelian isomorphic groups. Importantly, the groups resulting from the decomposition depend only on the original group and are therefore completely independent of both the automaton and the considered property. Consequently, they do not inherit any aspect of the complexity of the automaton under investigation. We study the inheritance of the dynamical properties in the original GCA versus the same properties in the GCA obtained through decomposition. The latter turn out to be significantly easier to analyze than in the original GCA. Then, we show that injectivity, surjectivity, and equicontinuity/sensitivity to initial conditions can be decided by testing them in the smaller GCA produced by the decomposition. Moreover, we prove that the topological entropy of a GCA can be computed, provided one knows how to compute it for GCA defined on products of simple non-abelian isomorphic groups – for which we explicitly prove how to compute it in the surjective case – and on abelian groups. Finally, we prove that no strongly transitive, and therefore no positively expansive, GCA defined on non-abelian groups exist.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103749"},"PeriodicalIF":0.9,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736654","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

Core stability in additively separable hedonic games of low treewidth 低树宽的可加可分享乐对策的核心稳定性

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2025-12-09 DOI: 10.1016/j.jcss.2025.103748

Tesshu Hanaka , Noleen Köhler , Michael Lampis

Additively Separable Hedonic Games (ASHGs) are coalition-formation games where we are given a directed graph whose vertices represent n selfish agents and the weight of each arc uv denotes the preferences of u for v. We revisit the computational complexity of the well-known notion of core stability of symmetric ASHGs, where the goal is to construct a partition of the agents into coalitions such that no group of agents would prefer to diverge from the given partition and form a new coalition. For Core Stability Verification (CSV), we first show the following hardness results: CSV remains coNP-complete on graphs of vertex cover 2; CSV is coW[1]-hard parameterized by vertex integrity when edge weights are encoded in unary; and CSV is coW[1]-hard parameterized by tree-depth even if all weights are from

{- 1, 1}

. We complement these results with essentially matching algorithms and an FPT algorithm parameterized by the treewidth tw plus the maximum degree Δ (improving a previous algorithm's dependence from

2^{O (tw Δ^{2})}

to

2^{O (tw Δ)}

). We then move on to study Core Stability (CS), which one would naturally expect to be even harder than CSV. We confirm this intuition by showing that CS is

Σ_{2}^{p}

-complete even on graphs of bounded vertex cover number. On the positive side, we present a

2^{2^{O (Δ tw)}} n^{O (1)}

-time algorithm parameterized by

tw + Δ

, which is essentially optimal assuming the Exponential Time Hypothesis (ETH). Finally, we consider the notion of k-core stability: k denotes the maximum size of the allowed blocking (diverging) coalitions. We show that k-CSV is coW[1]-hard parameterized by k (even on unweighted graphs), while k-CS is NP-complete for all

k \geq 3

(even on graphs of bounded degree with bounded edge weights).

加法分离变量享乐游戏(ASHGs)结盟是游戏,我们给出了一个有向图的顶点代表n自私的代理和每个电弧紫外的重量表示偏好的u v .我们重温著名的计算复杂度的概念核心稳定对称ASHGs,目标是构造一个分区的代理商等联盟,没有群宁愿偏离给定的分区和组建一个新的联合政府。对于核心稳定性验证（CSV），我们首先证明了以下硬度结果：CSV在顶点覆盖2的图上保持conp完全；当边权为一元编码时，CSV是顶点完整性的coW[1]-hard参数化；即使所有权值都来自{−1,1}，CSV仍然是由树深度参数化的coW[1]-hard。我们用基本匹配的算法和由树宽tw加上最大程度Δ参数化的FPT算法来补充这些结果（将先前算法的依赖性从2O（twΔ2）提高到2O（twΔ））。然后我们继续学习核心稳定性（CS），人们自然会认为它比CSV更难。我们通过证明CS即使在有界顶点覆盖数的图上也是Σ2p-complete来证实这个直觉。在积极的方面，我们提出了一个由tw+Δ参数化的22O（Δtw）nO(1)时间算法，该算法本质上是最优的，假设指数时间假设（ETH）。最后，我们考虑了k核稳定性的概念：k表示允许的阻塞（发散）联盟的最大大小。我们证明k- csv是由k（即使在无权图上）硬参数化的，而k- cs对于所有k≥3（即使在边权有界的有界度图上）是np完全的。

{"title":"Core stability in additively separable hedonic games of low treewidth","authors":"Tesshu Hanaka , Noleen Köhler , Michael Lampis","doi":"10.1016/j.jcss.2025.103748","DOIUrl":"10.1016/j.jcss.2025.103748","url":null,"abstract":"<div><div>Additively Separable Hedonic Games (ASHGs) are coalition-formation games where we are given a directed graph whose vertices represent n selfish agents and the weight of each arc uv denotes the preferences of u for v. We revisit the computational complexity of the well-known notion of core stability of symmetric ASHGs, where the goal is to construct a partition of the agents into coalitions such that no group of agents would prefer to diverge from the given partition and form a new coalition. For Core Stability Verification (CSV), we first show the following hardness results: CSV remains coNP-complete on graphs of vertex cover 2; CSV is coW[1]-hard parameterized by vertex integrity when edge weights are encoded in unary; and CSV is coW[1]-hard parameterized by tree-depth even if all weights are from <math><mo>{</mo><mo>−</mo><mn>1</mn><mo>,</mo><mn>1</mn><mo>}</mo></math>. We complement these results with essentially matching algorithms and an FPT algorithm parameterized by the treewidth tw plus the maximum degree Δ (improving a previous algorithm's dependence from <math><msup><mrow><mn>2</mn></mrow><mrow><mi>O</mi><mo>(</mo><mrow><mi>tw</mi></mrow><msup><mrow><mi>Δ</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></mrow></msup></math> to <math><msup><mrow><mn>2</mn></mrow><mrow><mi>O</mi><mo>(</mo><mrow><mi>tw</mi></mrow><mi>Δ</mi><mo>)</mo></mrow></msup></math>). We then move on to study Core Stability (CS), which one would naturally expect to be even harder than CSV. We confirm this intuition by showing that CS is <math><msubsup><mrow><mi>Σ</mi></mrow><mrow><mn>2</mn></mrow><mrow><mi>p</mi></mrow></msubsup></math>-complete even on graphs of bounded vertex cover number. On the positive side, we present a <math><msup><mrow><mn>2</mn></mrow><mrow><msup><mrow><mn>2</mn></mrow><mrow><mi>O</mi><mo>(</mo><mi>Δ</mi><mrow><mi>tw</mi></mrow><mo>)</mo></mrow></msup></mrow></msup><msup><mrow><mi>n</mi></mrow><mrow><mi>O</mi><mo>(</mo><mn>1</mn><mo>)</mo></mrow></msup></math>-time algorithm parameterized by <math><mrow><mi>tw</mi></mrow><mo>+</mo><mi>Δ</mi></math>, which is essentially optimal assuming the Exponential Time Hypothesis (ETH). Finally, we consider the notion of k-core stability: k denotes the maximum size of the allowed blocking (diverging) coalitions. We show that k-CSV is coW[1]-hard parameterized by k (even on unweighted graphs), while k-CS is NP-complete for all <math><mi>k</mi><mo>≥</mo><mn>3</mn></math> (even on graphs of bounded degree with bounded edge weights).</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103748"},"PeriodicalIF":0.9,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789682","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