Information Processing Letters最新文献

{"title":"Output bounds for conjunctions of path queries","authors":"Tamara Cucumides ,&nbsp;Juan Reutter ,&nbsp;Domagoj Vrgoč","doi":"10.1016/j.ipl.2026.106628","DOIUrl":"10.1016/j.ipl.2026.106628","url":null,"abstract":"<div><div>Conjunctive regular queries (CRQs) extend conjunctive regular path queries (CRPQs) by allowing path patterns defined through regular queries, a language that strictly generalizes regular path queries and underpins the recently published GQL standard. Despite their importance, little is known about how to derive tight output bounds for CRQs, which are crucial in the design of worst-case optimal algorithms. In this paper we extend the classical Atserias-Grohe-Marx (AGM) bound and the recent techniques for CRPQs to CRQs. We show that while the AGM approach provides general bounds, obtaining tight results requires refined information on the sets of nodes that can participate in the answers of regular queries. We introduce the use of derivation trees and marked nodes to capture this information, and show how they can be integrated into linear programs that yield tight bounds. We also provide lower bounds showing the optimality of our techniques. Our results strictly extend previous bounds for CRPQs, and offer new insights into the evaluation of richer query languages over graph databases.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"193 ","pages":"Article 106628"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385200","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":"Universal approximation theorem for neural networks with inputs from a topological vector space","authors":"Vugar E. Ismailov","doi":"10.1016/j.ipl.2026.106623","DOIUrl":"10.1016/j.ipl.2026.106623","url":null,"abstract":"<div><div>We study feedforward neural networks with inputs from a topological vector space (TVS-FNNs). Unlike traditional feedforward neural networks, TVS-FNNs can process a broader range of inputs, including sequences, matrices, functions and more. We prove a universal approximation theorem for TVS-FNNs, which demonstrates their capacity to approximate any continuous function defined on this expanded input space.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"193 ","pages":"Article 106623"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146022655","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":"A class of cubic polynomial semi-bent functions over F2n","authors":"Yan-Ping Wang ,&nbsp;Zhengbang Zha ,&nbsp;Weiguo Zhang ,&nbsp;Dengguo Feng","doi":"10.1016/j.ipl.2026.106625","DOIUrl":"10.1016/j.ipl.2026.106625","url":null,"abstract":"<div><div>Semi-bent functions play an important role in coding theory, symmetric ciphers, and sequence designs. In this paper, by decomposing cubic Boolean functions and describing the two-to-one property of polynomials, we characterize a class of cubic polynomial semi-bent functions over <span><math><msub><mi>F</mi><msup><mn>2</mn><mi>n</mi></msup></msub></math></span>.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"193 ","pages":"Article 106625"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385069","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":"LR parsing for strings with placeholders","authors":"Kohei Nakamichi,&nbsp;Akimasa Morihata,&nbsp;Tomoki Nakamaru","doi":"10.1016/j.ipl.2026.106627","DOIUrl":"10.1016/j.ipl.2026.106627","url":null,"abstract":"<div><div>This paper studies a parsing method for strings containing placeholders, each of which may be later replaced by a string derived from the corresponding nonterminal symbol. Such a method potentially applies to parallel/distributed parsing, parsing for templates, modular syntax definitions, and so on. This paper investigates whether the introduction of the placeholder preserves the class of the grammar and proves the following two facts. First, the class of LR(<em>k</em>)grammars is preserved if <em>k</em> ≥ 1 and every nonterminal derives at least one nonempty string; hence, we can apply the standard LR parsing algorithm for parsing strings with placeholders. Second, the class of LR(0) is not. These results extend the preceding study for the LL(1) grammars.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"193 ","pages":"Article 106627"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385199","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":"The k-center problem of uncertain points on graphs","authors":"Haitao Xu,&nbsp;Jingru Zhang","doi":"10.1016/j.ipl.2026.106621","DOIUrl":"10.1016/j.ipl.2026.106621","url":null,"abstract":"<div><div>In this paper, we study the <em>k</em>-center problem of uncertain points on a graph. Given are an undirected simple graph <span><math><mrow><mi>G</mi><mo>=</mo><mo>(</mo><mi>V</mi><mo>,</mo><mi>E</mi><mo>)</mo></mrow></math></span> and a set <span><math><mi>P</mi></math></span> of <em>n</em> uncertain points where each uncertain point with a non-negative weight has <em>m</em> possible locations on <em>G</em> each associated with a probability. The problem aims to find <em>k</em> centers (points) on <em>G</em> so as to minimize the maximum weighted expected distance of uncertain points to their own expected closest centers. No previous work exist for the <em>k</em>-center problem of uncertain points on undirected graphs. We propose exact algorithms that solve respectively the case of <span><math><mrow><mi>k</mi><mo>=</mo><mn>2</mn></mrow></math></span> in <em>O</em>(|<em>E</em>|²<em>m</em>²<em>n</em>log |<em>E</em>|<em>mn</em>log <em>mn</em>) time and the problem with <em>k</em> ≥ 3 in <span><math><mrow><msup><mrow><mi>O</mi><mo>(</mo><mi>min</mi><mo>{</mo><mo>|</mo><mi>E</mi><mo>|</mo></mrow><mi>k</mi></msup><msup><mi>m</mi><mi>k</mi></msup><msup><mi>n</mi><mrow><mi>k</mi><mo>+</mo><mn>1</mn></mrow></msup><msup><mrow><mi>k</mi><mi>log</mi><mo>|</mo><mi>E</mi><mo>|</mo><mi>m</mi><mi>n</mi><mi>log</mi><mi>m</mi><mo>,</mo><mo>|</mo><mi>E</mi><mo>|</mo></mrow><mi>k</mi></msup><msup><mi>n</mi><mfrac><mi>k</mi><mn>2</mn></mfrac></msup><msup><mi>m</mi><mfrac><msup><mi>k</mi><mn>2</mn></msup><mn>2</mn></mfrac></msup><mrow><mi>log</mi><mo>|</mo><mi>E</mi><mo>|</mo><mi>m</mi><mi>n</mi><mo>}</mo><mo>)</mo></mrow></mrow></math></span> time, provided with the distance matrix of <em>G</em>. In addition, an <em>O</em>(|<em>E</em>|<em>mn</em>log <em>mn</em>)-time algorithmic approach is given for the one-center case.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"193 ","pages":"Article 106621"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977795","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":"The complexity of HyperQPTL","authors":"Gaëtan Regaud ,&nbsp;Martin Zimmermann","doi":"10.1016/j.ipl.2026.106626","DOIUrl":"10.1016/j.ipl.2026.106626","url":null,"abstract":"<div><div>HyperQPTL and HyperQPTL<span><math><msup><mrow></mrow><mo>+</mo></msup></math></span> are expressive specification languages for hyperproperties, properties that relate multiple executions of a system. Tight complexity bounds are known for HyperQPTL finite-state satisfiability and model-checking.</div><div>Here, we settle the complexity of satisfiability for HyperQPTL as well as satisfiability, finite-state satisfiability, and model-checking for HyperQPTL<span><math><msup><mrow></mrow><mo>+</mo></msup></math></span>: the former is <span><math><msubsup><mstyle><mi>Σ</mi></mstyle><mn>1</mn><mn>2</mn></msubsup></math></span>-complete, the latter are all equivalent to truth in third-order arithmetic, i.e., all four are very undecidable.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"193 ","pages":"Article 106626"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385198","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":"A linear-time algorithm for the two-color one-dimensional buttons & scissors","authors":"Suguru Hayata ,&nbsp;Hiro Ito","doi":"10.1016/j.ipl.2026.106622","DOIUrl":"10.1016/j.ipl.2026.106622","url":null,"abstract":"<div><div>The problem of determining whether a given board of the puzzle Buttons &amp; Scissors is solvable is known to be NP-complete. On the other hand, when the board is restricted to one dimension, it is known to be solvable in <em>O</em>(<em>n</em>³)-time for a board of size (length) <em>n</em>. This also holds when the button colors are limited to two colors. We provide a simple linear-time algorithm to determine whether an input of the Two-Color One-Dimensional Buttons &amp; Scissors problem is solvable. The algorithm uses a necessary and sufficient condition after applying a linear-time preprocessing.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"193 ","pages":"Article 106622"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977796","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":"EvenPath in directed single-crossing graphs","authors":"Archit Chauhan ,&nbsp;Chetan Gupta ,&nbsp;Vimal Raj Sharma","doi":"10.1016/j.ipl.2025.106613","DOIUrl":"10.1016/j.ipl.2025.106613","url":null,"abstract":"<div><div>Given a directed graph <em>G</em> and two of its vertices <em>s</em> and <em>t</em>, the <em>EvenPath</em> problem is to find an even-length path from <em>s</em> to <em>t</em>. The decision version of <em>EvenPath</em> problem for general directed graphs was shown to be <span>NP</span>-<span><math><mi>complete</mi></math></span> by LaPaugh and Papadimitriou [1]. Thus, it makes sense to discover the classes of graphs for which the <em>EvenPath</em> problem can be solved efficiently. The <em>EvenPath</em> problem for directed planar graphs and directed single-crossing-minor-free graphs is known to be solvable in polynomial-time [2, 3]. In our work, we extend the classes of graphs for which the <em>EvenPath</em> problem can be solved in polynomial-time to directed single-crossing graphs. Our polynomial-time algorithm essentially reduces the <em>EvenPath</em> problem for a directed single-crossing graph to several instances of the <em>EvenPath</em> problem and 3-<em>DisjointPaths</em> problem for directed planar graphs.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"193 ","pages":"Article 106613"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145665346","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":"Finding partite hypergraphs efficiently","authors":"Ferran Espuña","doi":"10.1016/j.ipl.2026.106624","DOIUrl":"10.1016/j.ipl.2026.106624","url":null,"abstract":"<div><div>We provide a deterministic polynomial-time algorithm (for fixed <em>k</em>) that, for a given <em>k</em>-uniform hypergraph <em>H</em> with <em>n</em> vertices and edge density <em>d</em>, finds a complete <em>k</em>-partite subgraph of <em>H</em> with parts of size at least <span><math><mrow><mi>c</mi><mrow><mo>(</mo><mi>d</mi><mo>,</mo><mi>k</mi><mo>)</mo></mrow><msup><mrow><mo>(</mo><mi>log</mi><mi>n</mi><mo>)</mo></mrow><mrow><mn>1</mn><mo>/</mo><mo>(</mo><mi>k</mi><mo>−</mo><mn>1</mn><mo>)</mo></mrow></msup></mrow></math></span>. This generalizes work by Mubayi and Turán on bipartite graphs. The value we obtain for the part size matches the order of magnitude guaranteed by the non-constructive proof due to Erdős and is tight up to a constant factor.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"193 ","pages":"Article 106624"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385197","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":"Faster and simpler online computation of string net frequency","authors":"Shunsuke Inenaga","doi":"10.1016/j.ipl.2026.106620","DOIUrl":"10.1016/j.ipl.2026.106620","url":null,"abstract":"<div><div>An occurrence of a repeated substring <em>u</em> in a string <em>S</em> is called a <em>net occurrence</em> if extending the occurrence to the left or to the right decreases the number of occurrences to 1. The <em>net frequency</em> (<em>NF</em>) of a repeated substring <em>u</em> in a string <em>S</em> is the number of net occurrences of <em>u</em> in <em>S</em>. Very recently, Guo et al. [SPIRE 2024] proposed an online <em>O</em>(<em>n</em>log <em>σ</em>)-time algorithm that maintains a data structure of <em>O</em>(<em>n</em>) space which answers <span>Single-NF</span> queries in <span><math><mrow><mi>O</mi><mo>(</mo><mi>m</mi><mi>log</mi><mi>σ</mi><mo>+</mo><msup><mi>σ</mi><mn>2</mn></msup><mo>)</mo></mrow></math></span> time and reports all answers of the <span>All-NF</span> problem in <em>O</em>(<em>nσ</em>²) time. Here, <em>n</em> is the length of the input string <em>S, m</em> is the query pattern length, and <em>σ</em> is the alphabet size. The <em>σ</em>² term is a major drawback of their method since computing string net frequencies is originally motivated for Chinese language text processing where <em>σ</em> can be thousands large. This paper presents an improved online <em>O</em>(<em>n</em>log <em>σ</em>)-time algorithm, which answers <span>Single-NF</span> queries in <em>O</em>(<em>m</em>log <em>σ</em>) time and reports all answers to the <span>All-NF</span> problem in output-optimal <span><math><mrow><mi>O</mi><mo>(</mo><mo>|</mo><msup><mi>NF</mi><mo>+</mo></msup><mrow><mo>(</mo><mi>S</mi><mo>)</mo></mrow><mo>|</mo><mo>)</mo></mrow></math></span> time, where <span><math><mrow><msup><mi>NF</mi><mo>+</mo></msup><mrow><mo>(</mo><mi>S</mi><mo>)</mo></mrow></mrow></math></span> is the set of substrings of <em>S</em> paired with their positive NF values. We note that <span><math><mrow><mrow><mo>|</mo></mrow><msup><mi>NF</mi><mo>+</mo></msup><mrow><mrow><mo>(</mo><mi>S</mi><mo>)</mo></mrow><mo>|</mo><mo>=</mo><mi>O</mi><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow></mrow></mrow></math></span> always holds. In contrast to Guo et al.’s algorithm that is based on Ukkonen’s suffix tree construction, our algorithm is based on Weiner’s suffix tree construction.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"193 ","pages":"Article 106620"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146022656","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}