Information and Computation最新文献

{"title":"Metric quantifiers and counting in timed logics and automata","authors":"Hsi-Ming Ho ,&nbsp;Khushraj Madnani","doi":"10.1016/j.ic.2025.105268","DOIUrl":"10.1016/j.ic.2025.105268","url":null,"abstract":"<div><div>We study the expressiveness of the <em>pointwise</em> interpretations (i.e. over timed words) of some predicate and temporal logics with metric and counting features. We show that counting in the unit interval <span><math><mo>(</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>)</mo></math></span> is strictly weaker than counting in <span><math><mo>(</mo><mn>0</mn><mo>,</mo><mi>b</mi><mo>)</mo></math></span> with arbitrary <span><math><mi>b</mi><mo>≥</mo><mn>0</mn></math></span>; moreover, allowing the latter to be included in temporal logics leads to expressive completeness for the metric predicate logic <span>Q2MLO</span>, recovering the corresponding result for the continuous interpretations (i.e. over signals). Exploiting this connection, we show that in contrast to the continuous case, adding ‘punctual’ predicates into <span>Q2MLO</span> is still insufficient for the full expressive power of the Monadic First-Order Logic of Order and Metric (<span>FO[</span><span><math><mo>&lt;</mo><mo>,</mo><mo>+</mo><mn>1</mn></math></span><span>]</span>); as a remedy, we propose a generalisation of the recently proposed Pnueli automata modalities and show that the resulting metric temporal logic is expressively complete for <span>FO[</span><span><math><mo>&lt;</mo><mo>,</mo><mo>+</mo><mn>1</mn></math></span><span>]</span>. On the practical side, we propose a <em>compositional</em> construction from metric interval temporal logic with counting or similar extensions to timed automata, which is more amenable to implementation based on existing tools that support on-the-fly model checking.</div></div>","PeriodicalId":54985,"journal":{"name":"Information and Computation","volume":"303 ","pages":"Article 105268"},"PeriodicalIF":0.8,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Generalising the maximum independent set algorithm via Boolean networks","authors":"Maximilien Gadouleau,&nbsp;David C. Kutner","doi":"10.1016/j.ic.2025.105266","DOIUrl":"10.1016/j.ic.2025.105266","url":null,"abstract":"<div><div>A simple greedy algorithm to find a maximal independent set (MIS) in a graph starts with the empty set and visits every vertex, adding it to the set if and only if none of its neighbours are already in the set. In this paper, we consider (the complexity of decision problems related to) the generalisation of this MIS algorithm wherein any starting set is allowed. Two main approaches are leveraged. Firstly, we view the MIS algorithm as a sequential update of a Boolean network according to a permutation of the vertex set. Secondly, we introduce the concept of a constituency of a graph: a set of vertices that is dominated by an independent set. Recognizing a constituency is <strong>NP</strong>-complete, a fact we leverage repeatedly in our investigation.</div><div>Our contributions are multiple: we establish that deciding whether all maximal independent sets can be reached from some configuration is <strong>coNP</strong>-complete; that fixing words (which reach a MIS from any starting configuration) and fixing permutations (briefly, permises) are <strong>coNP</strong>-complete to recognize; and that permissible graphs (graphs with a permis) are <strong>coNP</strong>-hard to recognize. We also exhibit large classes of permissible and non-permissible graphs, notably near-comparability graphs which may be of independent interest.</div><div>Lastly, we extend our study to digraphs, where we search for kernels. Since the natural generalisation of our approach may not necessarily find a kernel, we introduce two further Boolean networks for digraphs: one always finds an independent set, and the other always finds a dominating set.</div></div>","PeriodicalId":54985,"journal":{"name":"Information and Computation","volume":"303 ","pages":"Article 105266"},"PeriodicalIF":0.8,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Efficient assignment of identities in anonymous populations","authors":"Leszek Gąsieniec ,&nbsp;Jesper Jansson ,&nbsp;Christos Levcopoulos ,&nbsp;Andrzej Lingas","doi":"10.1016/j.ic.2025.105265","DOIUrl":"10.1016/j.ic.2025.105265","url":null,"abstract":"<div><div>We consider the fundamental problem of assigning distinct labels to agents in the probabilistic model of population protocols. Our protocols operate under the assumption that the size <em>n</em> of the population is embedded in the transition function. W.h.p. (with high probability), they are silent, i.e., eventually each agent reaches its final state and remains in it forever, and they are safe, i.e., never change a label that has already been assigned to an agent. We provide efficient protocols for this problem complemented with tight lower bounds. Our fast labeling protocol uses only <span><math><mi>O</mi><mo>(</mo><mo>(</mo><mi>n</mi><mi>log</mi><mo>⁡</mo><mi>n</mi><mo>)</mo><mo>/</mo><mi>ε</mi><mo>)</mo></math></span> interactions w.h.p., <span><math><mo>(</mo><mn>2</mn><mo>+</mo><mi>ε</mi><mo>)</mo><mi>n</mi><mo>+</mo><mi>O</mi><mo>(</mo><msup><mrow><mi>n</mi></mrow><mrow><mi>a</mi></mrow></msup><mo>)</mo></math></span> states, and the label range <span><math><mo>[</mo><mn>1</mn><mo>,</mo><mo>(</mo><mn>1</mn><mo>+</mo><mi>ε</mi><mo>)</mo><mi>n</mi><mo>]</mo></math></span>, where <span><math><mn>1</mn><mo>≥</mo><mi>ε</mi><mo>&gt;</mo><mn>0</mn></math></span> and <span><math><mn>0</mn><mo>&lt;</mo><mi>a</mi><mo>&lt;</mo><mn>1</mn></math></span>, while our nearly state-optimal protocol uses only <span><math><mi>n</mi><mo>+</mo><mn>5</mn><msqrt><mrow><mi>n</mi></mrow></msqrt><mo>+</mo><mi>O</mi><mo>(</mo><mi>log</mi><mo>⁡</mo><mi>log</mi><mo>⁡</mo><mi>n</mi><mo>)</mo></math></span> states, the label range <span><math><mo>[</mo><mn>1</mn><mo>,</mo><mi>n</mi><mo>]</mo></math></span>, and w.h.p., <span><math><mi>O</mi><mo>(</mo><msup><mrow><mi>n</mi></mrow><mrow><mn>3</mn></mrow></msup><mo>)</mo></math></span> interactions.</div></div>","PeriodicalId":54985,"journal":{"name":"Information and Computation","volume":"303 ","pages":"Article 105265"},"PeriodicalIF":0.8,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Approximate envy-freeness in indivisible resource allocation with budget constraints","authors":"Xiaowei Wu ,&nbsp;Bo Li ,&nbsp;Jiarui Gan","doi":"10.1016/j.ic.2024.105264","DOIUrl":"10.1016/j.ic.2024.105264","url":null,"abstract":"<div><div>We study the fair allocation of indivisible resources under knapsack constraints, where a set of items with varied costs and values are to be allocated among a group of agents. Each agent has a budget constraint on the total cost of items she can receive. The goal is to compute a budget-feasible allocation that is <em>envy-free</em> (EF), in which the agents do not envy each other for the items they receive, nor do they envy a charity, which is endowed with all the unallocated items. Since EF allocations barely exist (even without the budget constraints), we are interested in the relaxed notion of <em>envy-freeness up to one item</em> (EF1). Our results are twofold. Firstly, for the general setting where agents have heterogeneous valuations and budgets, we show that a budget-feasible allocation that maximizes the <em>Nash social welfare</em> (NSW) achieves a 1/4-approximation of EF1. This approximation ratio carries to the general case of arbitrary monotone subadditive valuations. The approximation ratio improves gracefully when the items have small cost compared with the agents' budgets; it converges to 1/2 when the budget-cost ratio approaches infinity, and to 1 if the agents further have identical valuations. Secondly, when agents have identical valuations, we design a polynomial-time algorithm that computes a 1/2-approximate EF1 allocation for an arbitrary number of agents. For the case of identical agents and the case of two agents, we propose polynomial-time algorithms for computing EF1 allocations.</div></div>","PeriodicalId":54985,"journal":{"name":"Information and Computation","volume":"303 ","pages":"Article 105264"},"PeriodicalIF":0.8,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Succinctness issues for LTLf and safety and cosafety fragments of LTL","authors":"Alessandro Artale ,&nbsp;Luca Geatti ,&nbsp;Nicola Gigante ,&nbsp;Andrea Mazzullo ,&nbsp;Angelo Montanari","doi":"10.1016/j.ic.2024.105262","DOIUrl":"10.1016/j.ic.2024.105262","url":null,"abstract":"<div><div>Linear Temporal Logic over finite traces (<span>LTL</span>_{<span>f</span>}) has proved itself to be an important and effective formalism in formal verification as well as in artificial intelligence. Pure past <span>LTL</span>_{<span>f</span>} (<span>pLTL</span>) is the variant of <span>LTL</span>_{<span>f</span>} featuring only past temporal modalities, and is naturally interpreted at the end of a finite trace. It is known that each property definable in <span>LTL</span>_{<span>f</span>} is also definable in <span>pLTL</span>, and <em>vice versa</em> (they are expressively equivalent). The same goes for the <em>safety</em> and <em>cosafety</em> fragments of Linear Temporal Logic over infinite traces (<span>LTL</span>), when compared to <span>G</span>(<span>pLTL</span>) and <span>F</span>(<span>pLTL</span>) formulas, respectively, that is, <span>pLTL</span> formulas prefixed by a <em>globally</em> and an <em>eventually</em> modality. However, despite being extensively used in practice, to the best of our knowledge, there is no systematic study of their succinctness. Moreover, when considering (co)safety fragments of <span>LTL</span> devoid of binary temporal modalities, there are no known characterizations based on <span>pLTL</span>.</div><div>In this paper, we investigate succinctness issues for <span>LTL</span>_{<span>f</span>} and (co)safety fragments of <span>LTL</span> when compared with their pure past counterparts. First, we provide a pure past characterization of the (co)safety fragments of <span><math><mi>LTL</mi></math></span> devoid of binary temporal modalities. Then, we prove that the (co)safety fragments of <span><math><mi>LTL</mi></math></span> have pure past counterparts that can be exponentially more succinct. Finally, we show that the same holds for <span><math><msub><mrow><mi>LTL</mi></mrow><mrow><mi>f</mi></mrow></msub></math></span> with respect to <span><math><mi>pLTL</mi></math></span>, and viceversa: <span><math><msub><mrow><mi>LTL</mi></mrow><mrow><mi>f</mi></mrow></msub></math></span> and <span><math><mi>pLTL</mi></math></span> are incomparable when succinctness is concerned.</div></div>","PeriodicalId":54985,"journal":{"name":"Information and Computation","volume":"302 ","pages":"Article 105262"},"PeriodicalIF":0.8,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Universal complexity bounds based on value iteration for stochastic mean payoff games and entropy games","authors":"Xavier Allamigeon ,&nbsp;Stéphane Gaubert ,&nbsp;Ricardo D. Katz ,&nbsp;Mateusz Skomra","doi":"10.1016/j.ic.2024.105236","DOIUrl":"10.1016/j.ic.2024.105236","url":null,"abstract":"<div><div>We develop value iteration-based algorithms to solve in a unified manner different classes of combinatorial zero-sum games with mean-payoff type rewards. These algorithms rely on an oracle, evaluating the dynamic programming operator up to a given precision. We show that the number of calls to the oracle needed to determine exact optimal (positional) strategies is, up to a factor polynomial in the dimension, of order <span><math><mi>R</mi><mo>/</mo><mi>sep</mi></math></span>, where the “separation” sep is defined as the minimal difference between distinct values arising from strategies, and <em>R</em> is a metric estimate, involving the norm of approximate sub and super-eigenvectors of the dynamic programming operator. We illustrate this method by two applications. The first one is a new proof, leading to improved complexity estimates, of a theorem of Boros, Elbassioni, Gurvich and Makino, showing that turn-based mean-payoff games with a fixed number of random positions can be solved in pseudo-polynomial time. The second one concerns entropy games, a model introduced by Asarin, Cervelle, Degorre, Dima, Horn and Kozyakin. The <em>rank</em> of an entropy game is defined as the maximal rank among all the ambiguity matrices determined by strategies of the two players. We show that entropy games with a fixed rank, in their original formulation, can be solved in polynomial time, and that an extension of entropy games incorporating weights can be solved in pseudo-polynomial time under the same fixed rank condition.</div></div>","PeriodicalId":54985,"journal":{"name":"Information and Computation","volume":"302 ","pages":"Article 105236"},"PeriodicalIF":0.8,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Preface: Selected papers from SSS'2019, the 21st International Symposium on Stabilization, Safety, and Security of Distributed Systems","authors":"Mikhail Nesterenko,&nbsp;Sébastien Tixeuil,&nbsp;Sara Tucci,&nbsp;Yukiko Yamauchi","doi":"10.1016/j.ic.2023.105034","DOIUrl":"10.1016/j.ic.2023.105034","url":null,"abstract":"","PeriodicalId":54985,"journal":{"name":"Information and Computation","volume":"302 ","pages":"Article 105034"},"PeriodicalIF":0.8,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Special Issue of PLACES 2022","authors":"Marco Carbone,&nbsp;Nobuko Yoshida","doi":"10.1016/j.ic.2024.105263","DOIUrl":"10.1016/j.ic.2024.105263","url":null,"abstract":"","PeriodicalId":54985,"journal":{"name":"Information and Computation","volume":"302 ","pages":"Article 105263"},"PeriodicalIF":0.8,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Preface to special issue: EXPRESS/SOS 2019 and EXPRESS/SOS 2020","authors":"Ornela Dardha ,&nbsp;Jorge A. Pérez ,&nbsp;Jurriaan Rot","doi":"10.1016/j.ic.2024.105154","DOIUrl":"10.1016/j.ic.2024.105154","url":null,"abstract":"","PeriodicalId":54985,"journal":{"name":"Information and Computation","volume":"302 ","pages":"Article 105154"},"PeriodicalIF":0.8,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Preface to “Computation over Compressed Data” at DCC 2022","authors":"Travis Gagie ,&nbsp;Nicola Prezza","doi":"10.1016/j.ic.2024.105165","DOIUrl":"10.1016/j.ic.2024.105165","url":null,"abstract":"","PeriodicalId":54985,"journal":{"name":"Information and Computation","volume":"302 ","pages":"Article 105165"},"PeriodicalIF":0.8,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}