Pub Date : 2025-08-29DOI: 10.1016/j.ipl.2025.106598
Tianqi Chen, Zhiyi Tan
This paper investigates the non-clairvoyant parallel machine scheduling problem with prediction, with the objective of minimizing the makespan. Improved lower bounds for the problem and competitive ratios of online algorithms with respect to the prediction error are presented for both the non-preemptive and preemptive cases on m identical machines.
{"title":"Tighter bounds on non-clairvoyant parallel machine scheduling with prediction to minimize makespan","authors":"Tianqi Chen, Zhiyi Tan","doi":"10.1016/j.ipl.2025.106598","DOIUrl":"10.1016/j.ipl.2025.106598","url":null,"abstract":"<div><div>This paper investigates the non-clairvoyant parallel machine scheduling problem with prediction, with the objective of minimizing the makespan. Improved lower bounds for the problem and competitive ratios of online algorithms with respect to the prediction error are presented for both the non-preemptive and preemptive cases on <em>m</em> identical machines.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"191 ","pages":"Article 106598"},"PeriodicalIF":0.6,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144922608","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}
Pub Date : 2025-08-29DOI: 10.1016/j.ipl.2025.106597
Marcin Peczarski
We present generalized approach to the proof of the lower bound for unburnt pancake sorting problem, where we search for the number of prefix reversals required to sort a stack (permutation) of n pancakes. For this purpose we introduce a new concept of guarded pancake blocks. Gates and Papadimitriou proved that for n a multiple of 16. Heydari and Sudborough improved this bound to for n a multiple of 14. We extend that result to for every .
{"title":"Note on pancake sorting","authors":"Marcin Peczarski","doi":"10.1016/j.ipl.2025.106597","DOIUrl":"10.1016/j.ipl.2025.106597","url":null,"abstract":"<div><div>We present generalized approach to the proof of the lower bound for unburnt pancake sorting problem, where we search for the number <span><math><mi>f</mi><mo>(</mo><mi>n</mi><mo>)</mo></math></span> of prefix reversals required to sort a stack (permutation) of <em>n</em> pancakes. For this purpose we introduce a new concept of guarded pancake blocks. Gates and Papadimitriou proved that <span><math><mi>f</mi><mo>(</mo><mi>n</mi><mo>)</mo><mo>≥</mo><mn>17</mn><mi>n</mi><mo>/</mo><mn>16</mn></math></span> for <em>n</em> a multiple of 16. Heydari and Sudborough improved this bound to <span><math><mi>f</mi><mo>(</mo><mi>n</mi><mo>)</mo><mo>≥</mo><mn>15</mn><mi>n</mi><mo>/</mo><mn>14</mn></math></span> for <em>n</em> a multiple of 14. We extend that result to <span><math><mi>f</mi><mo>(</mo><mi>n</mi><mo>)</mo><mo>≥</mo><mo>⌊</mo><mo>(</mo><mn>15</mn><mi>n</mi><mo>+</mo><mn>9</mn><mo>)</mo><mo>/</mo><mn>14</mn><mo>⌋</mo></math></span> for every <span><math><mi>n</mi><mo>≥</mo><mn>6</mn></math></span>.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"191 ","pages":"Article 106597"},"PeriodicalIF":0.6,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144922609","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}
Pub Date : 2025-07-18DOI: 10.1016/j.ipl.2025.106596
Xian Xu , Wenbo Zhang
Quantitative aspects like probabilities play an important role in concurrent processes. Providing a (modal) logic for a randomized concurrency model can augment the toolbox of analyzing probabilistic processes, and thus is a frequent topic in the field. In this paper, we are interested in logically characterizing uniformly randomized processes, whose semantical behavior is defined in a model-independent manner. Specifically, we present two modal logics for the uniformly randomized version of finite-state CCS (RCCSfsfor short). Our logics extend the Hennessy-Milner logic, and one of them is equipped with the μ operator. Indeed, we prove that both logics characterize the branching bisimilarity for RCCSfs, i.e., two RCCSfsprocesses are branching bisimilar if and only if they are logically equivalent. To facilitate the proof, we also develop for RCCSfsan up-to proof method, which may be of independent interest.
{"title":"Logical characterization of branching bisimilarity over random processes","authors":"Xian Xu , Wenbo Zhang","doi":"10.1016/j.ipl.2025.106596","DOIUrl":"10.1016/j.ipl.2025.106596","url":null,"abstract":"<div><div>Quantitative aspects like probabilities play an important role in concurrent processes. Providing a (modal) logic for a randomized concurrency model can augment the toolbox of analyzing probabilistic processes, and thus is a frequent topic in the field. In this paper, we are interested in logically characterizing uniformly randomized processes, whose semantical behavior is defined in a model-independent manner. Specifically, we present two modal logics for the uniformly randomized version of finite-state CCS (RCCS<sub>fs</sub>for short). Our logics extend the Hennessy-Milner logic, and one of them is equipped with the <em>μ</em> operator. Indeed, we prove that both logics characterize the branching bisimilarity for RCCS<sub>fs</sub>, i.e., two RCCS<sub>fs</sub>processes are branching bisimilar if and only if they are logically equivalent. To facilitate the proof, we also develop for RCCS<sub>fs</sub>an up-to proof method, which may be of independent interest.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"191 ","pages":"Article 106596"},"PeriodicalIF":0.7,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144679662","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}
Pub Date : 2025-07-15DOI: 10.1016/j.ipl.2025.106595
Vladimir Edemskiy, Zeyu Cao
In this paper, we study the linear complexity of quaternary cyclotomic sequences with period p, where is a prime. Considered sequences are based on classical cyclotomic classes of order four modulo p. We show that any balanced quaternary cyclotomic sequence of order four with period p has high linear complexity over finite ring of order four. Our results generalize those obtained earlier by other authors.
{"title":"Notes about the linear complexity of quaternary cyclotomic sequences of order four","authors":"Vladimir Edemskiy, Zeyu Cao","doi":"10.1016/j.ipl.2025.106595","DOIUrl":"10.1016/j.ipl.2025.106595","url":null,"abstract":"<div><div>In this paper, we study the linear complexity of quaternary cyclotomic sequences with period <em>p</em>, where <span><math><mi>p</mi><mo>></mo><mn>2</mn></math></span> is a prime. Considered sequences are based on classical cyclotomic classes of order four modulo <em>p</em>. We show that any balanced quaternary cyclotomic sequence of order four with period <em>p</em> has high linear complexity over finite ring of order four. Our results generalize those obtained earlier by other authors.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"191 ","pages":"Article 106595"},"PeriodicalIF":0.7,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144633879","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}
Pub Date : 2025-06-16DOI: 10.1016/j.ipl.2025.106594
Roberto Grossi , Costas S. Iliopoulos , Jesper Jansson , Zara Lim , Wing-Kin Sung , Wiktor Zuba
We introduce the concept of cyclic covers, which generalizes the classical notion of covers in strings. Given any string X, a factor W of X is called a cyclic cover if each position of X belongs to an occurrence of a cyclic shift of W in X. Two cyclic covers are distinct if one is not a cyclic shift of the other. The cyclic covers problem asks for all distinct cyclic covers of an input string X. We present an algorithm that solves the cyclic covers problem in time, where n is the length of X. It is based on finding a well-structured set of standard occurrences of a constant number of factors of a cyclic cover candidate W, computing the regions of X covered by cyclic shifts of W, extending those factors, and taking the union of the results.
{"title":"Finding the cyclic covers of a string","authors":"Roberto Grossi , Costas S. Iliopoulos , Jesper Jansson , Zara Lim , Wing-Kin Sung , Wiktor Zuba","doi":"10.1016/j.ipl.2025.106594","DOIUrl":"10.1016/j.ipl.2025.106594","url":null,"abstract":"<div><div>We introduce the concept of cyclic covers, which generalizes the classical notion of covers in strings. Given any string <em>X</em>, a factor <em>W</em> of <em>X</em> is called a <em>cyclic cover</em> if each position of <em>X</em> belongs to an occurrence of a cyclic shift of <em>W</em> in <em>X</em>. Two cyclic covers are distinct if one is not a cyclic shift of the other. The <em>cyclic covers problem</em> asks for all distinct cyclic covers of an input string <em>X</em>. We present an algorithm that solves the cyclic covers problem in <span><math><mi>O</mi><mo>(</mo><mi>n</mi><mi>log</mi><mo></mo><mi>n</mi><mo>)</mo></math></span> time, where <em>n</em> is the length of <em>X</em>. It is based on finding a well-structured set of standard occurrences of a constant number of factors of a cyclic cover candidate <em>W</em>, computing the regions of <em>X</em> covered by cyclic shifts of <em>W</em>, extending those factors, and taking the union of the results.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"191 ","pages":"Article 106594"},"PeriodicalIF":0.7,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144298426","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}
Pub Date : 2025-06-11DOI: 10.1016/j.ipl.2025.106593
Manoj Gyawali
Lattice isomorphism problem (LIP) has been studied since 1990s. In 2023, a post-quantum signature scheme known as HAWK was submitted in the NIST standardization of additional signature scheme, which is based on the module lattice isomorphism problem (module-LIP). Module-LIP was formally defined by Mureau et al. at Eurocrypt'24 and Luo et al. reduced the problem of solving module-LIP over CM number fields to a problem of finding the special type of symplectic automorphism.
In this paper, we extend this idea further by establishing a reduction of the module-LIP to a problem of finding special types of matrices.
晶格同构问题（LIP）自20世纪90年代开始研究。2023年，在NIST附加签名方案标准化中提交了一个基于模块格同构问题（module- lip）的后量子签名方案HAWK。Module-LIP是由mueau et al.在Eurocrypt'24上正式定义的，Luo等人将求解CM数域上的Module-LIP问题简化为寻找特殊类型的辛自同构问题。在本文中，我们进一步扩展了这一思想，将模- lip简化为寻找特殊类型矩阵的问题。
{"title":"Rank-2 module-LIP with special matrices","authors":"Manoj Gyawali","doi":"10.1016/j.ipl.2025.106593","DOIUrl":"10.1016/j.ipl.2025.106593","url":null,"abstract":"<div><div>Lattice isomorphism problem (LIP) has been studied since 1990s. In 2023, a post-quantum signature scheme known as HAWK was submitted in the NIST standardization of additional signature scheme, which is based on the module lattice isomorphism problem (module-LIP). Module-LIP was formally defined by Mureau et al. at Eurocrypt'24 and Luo et al. reduced the problem of solving module-LIP over CM number fields to a problem of finding the special type of symplectic automorphism.</div><div>In this paper, we extend this idea further by establishing a reduction of the module-LIP to a problem of finding special types of matrices.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"191 ","pages":"Article 106593"},"PeriodicalIF":0.7,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270237","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}
Pub Date : 2025-06-04DOI: 10.1016/j.ipl.2025.106592
Bhawani Sankar Panda , Soumyashree Rana , Sounaka Mishra
We correct an error in Theorem 4 in our published paper Panda et al. [3].
我们在发表的论文Panda et al. b[3]中修正了定理4中的一个错误。
{"title":"Corrigendum to “On the complexity of co-secure dominating set problem” [Inf. Process. Lett. 185 (2024) 106463]","authors":"Bhawani Sankar Panda , Soumyashree Rana , Sounaka Mishra","doi":"10.1016/j.ipl.2025.106592","DOIUrl":"10.1016/j.ipl.2025.106592","url":null,"abstract":"<div><div>We correct an error in <span><span>Theorem 4</span></span> in our published paper Panda et al. <span><span>[3]</span></span>.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"191 ","pages":"Article 106592"},"PeriodicalIF":0.6,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145018711","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}
Pub Date : 2025-06-03DOI: 10.1016/j.ipl.2025.106590
Stefan Kiefer, Andrew Ryzhikov
The period of a strongly connected digraph is the greatest common divisor of the lengths of all its cycles. The period of a digraph is the least common multiple of the periods of its strongly connected components. These notions play an important role in the theory of Markov chains and the analysis of powers of nonnegative matrices. While the time complexity of computing the period is well-understood, little is known about its space complexity. We show that the problem of computing the period of a digraph is NL-complete, even if all its cycles are contained in the same strongly connected component. However, if the digraph is strongly connected, we show that this problem becomes L-complete. For primitive digraphs (that is, strongly connected digraphs of period one), there always exists a number m such that there is a path of length exactly m between every two vertices. We show that computing the smallest such m, called the exponent of a digraph, is NL-complete. The exponent of a primitive digraph is a particular case of the index of convergence of a nonnegative matrix, which we also show to be computable in NL, and thus NL-complete.
{"title":"The complexity of computing the period and the exponent of a digraph","authors":"Stefan Kiefer, Andrew Ryzhikov","doi":"10.1016/j.ipl.2025.106590","DOIUrl":"10.1016/j.ipl.2025.106590","url":null,"abstract":"<div><div>The period of a strongly connected digraph is the greatest common divisor of the lengths of all its cycles. The period of a digraph is the least common multiple of the periods of its strongly connected components. These notions play an important role in the theory of Markov chains and the analysis of powers of nonnegative matrices. While the time complexity of computing the period is well-understood, little is known about its space complexity. We show that the problem of computing the period of a digraph is <span>NL</span>-complete, even if all its cycles are contained in the same strongly connected component. However, if the digraph is strongly connected, we show that this problem becomes <span>L</span>-complete. For primitive digraphs (that is, strongly connected digraphs of period one), there always exists a number <em>m</em> such that there is a path of length exactly <em>m</em> between every two vertices. We show that computing the smallest such <em>m</em>, called the exponent of a digraph, is <span>NL</span>-complete. The exponent of a primitive digraph is a particular case of the index of convergence of a nonnegative matrix, which we also show to be computable in <span>NL</span>, and thus <span>NL</span>-complete.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"191 ","pages":"Article 106590"},"PeriodicalIF":0.7,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144241718","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}
Pub Date : 2025-06-02DOI: 10.1016/j.ipl.2025.106591
Zihui Liu
We give further results on the weight distributions of the two families of binary codes recently constructed by simplicial complexes by (Wu, Lee, 2020), and show that the converse of the above results is also correct, that is, the binary codes with such weight distributions properties must be these two families of codes. Based on the above results, we also construct another family of binary self-orthogonal codes and present their separating properties and applications to the secret sharing scheme, cryptography and other aspects of information security.
{"title":"On some families of binary codes","authors":"Zihui Liu","doi":"10.1016/j.ipl.2025.106591","DOIUrl":"10.1016/j.ipl.2025.106591","url":null,"abstract":"<div><div>We give further results on the weight distributions of the two families of binary codes recently constructed by simplicial complexes by (Wu, Lee, 2020), and show that the converse of the above results is also correct, that is, the binary codes with such weight distributions properties must be these two families of codes. Based on the above results, we also construct another family of binary self-orthogonal codes and present their separating properties and applications to the secret sharing scheme, cryptography and other aspects of information security.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"191 ","pages":"Article 106591"},"PeriodicalIF":0.7,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144195768","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}
Pub Date : 2025-05-19DOI: 10.1016/j.ipl.2025.106589
Sam Buss , Neil Thapen
We describe CNFs in n variables which, over a range of parameters, have small resolution refutations but are such that any small refutation must have height larger than n (even exponential in n), where the height of a refutation is the length of the longest path in it. This is called a supercritical tradeoff between size and height because, if we do not care about size, every CNF is refutable in height n. Our proof method uses a simple construction, based on or-ification and base d representations of integers, to reduce the number of variables. A similar result appeared in [Fleming, Pitassi and Robere, ITCS '22], for different formulas using a more complicated construction for reducing the number of variables.
Small refutations of our formula are necessarily highly irregular, making it a plausible candidate to separate resolution from pool resolution, which amounts to separating CDCL with restarts from CDCL without restarts. We are not able to show this. In the other direction, we show that a simpler version of our formula, with a similar irregularity property, does have polynomial size pool resolution refutations and thus does not provide such a separation for CDCL.
{"title":"A simple supercritical tradeoff between size and height in resolution","authors":"Sam Buss , Neil Thapen","doi":"10.1016/j.ipl.2025.106589","DOIUrl":"10.1016/j.ipl.2025.106589","url":null,"abstract":"<div><div>We describe CNFs in <em>n</em> variables which, over a range of parameters, have small resolution refutations but are such that any small refutation must have height larger than <em>n</em> (even exponential in <em>n</em>), where the height of a refutation is the length of the longest path in it. This is called a <em>supercritical</em> tradeoff between size and height because, if we do not care about size, every CNF is refutable in height <em>n</em>. Our proof method uses a simple construction, based on or-ification and base <em>d</em> representations of integers, to reduce the number of variables. A similar result appeared in [Fleming, Pitassi and Robere, ITCS '22], for different formulas using a more complicated construction for reducing the number of variables.</div><div>Small refutations of our formula are necessarily highly irregular, making it a plausible candidate to separate resolution from pool resolution, which amounts to separating CDCL with restarts from CDCL without restarts. We are not able to show this. In the other direction, we show that a simpler version of our formula, with a similar irregularity property, <em>does</em> have polynomial size pool resolution refutations and thus does not provide such a separation for CDCL.</div></div>","PeriodicalId":56290,"journal":{"name":"Information Processing Letters","volume":"191 ","pages":"Article 106589"},"PeriodicalIF":0.7,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144125176","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}
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