Acta Informatica最新文献

Spanning cactus and spanning cactus extension of outerplanar graphs 外平面图的生成仙人掌和生成仙人掌的扩展

IF 0.5 4区计算机科学

Acta Informatica Pub Date : 2025-09-24 DOI: 10.1007/s00236-025-00506-x

Chinmay Debnath, Alak Kumar Datta

引用次数: 0

Shortest characteristic factors of a deterministic finite automaton and computing its positive position run by pattern set matching 确定有限自动机的最短特征因子及基于模式集匹配的正位置计算

IF 0.5 4区计算机科学

Acta Informatica Pub Date : 2025-09-10 DOI: 10.1007/s00236-025-00484-0

Jan Janoušek, Štěpán Plachý

{"title":"Shortest characteristic factors of a deterministic finite automaton and computing its positive position run by pattern set matching","authors":"Jan Janoušek, Štěpán Plachý","doi":"10.1007/s00236-025-00484-0","DOIUrl":"10.1007/s00236-025-00484-0","url":null,"abstract":"<div>Given a deterministic finite automaton (DFA) A, we present a simple algorithm for constructing deterministic finite automata that accept the shortest forbidden factors, the shortest forbidden prefixes, the shortest forbidden suffixes, the shortest forbidden words, the shortest allowed suffixes, and the shortest allowed words of the automaton A. We refer to these sets as the shortest characteristic factors of the automaton A. If the given automaton is local, and therefore the language it accepts is strictly locally testable, the sets of its shortest characteristic factors are finite, and these automata are acyclic. Otherwise, they accept infinite languages. This approach simplifies existing methods for the extraction of forbidden factors, allows the extraction of more types of characteristic factors, and also generalizes the extraction for all classes of DFAs. Furthermore, we demonstrate that this type of extraction can be used for a sublinear run of an automaton for certain inputs. We define a positive position run of a deterministic finite automaton, representing all positions in an input string where the automaton reaches a final state. Finally, we present an algorithm for computing the positive position run of the automaton, which utilizes pattern set matching of its shortest forbidden factors and its shortest forbidden or allowed suffixes, provided that the sets are finite. We showcase the computation of the positive position run of a local automaton using backward pattern set matching, which can achieve sublinear time.</div>","PeriodicalId":7189,"journal":{"name":"Acta Informatica","volume":"62 3","pages":""},"PeriodicalIF":0.5,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00236-025-00484-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145021493","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}

引用次数: 0

Parameterized lower bounds for the weighted vertex cover problem in trees 树中加权顶点覆盖问题的参数化下界

IF 0.5 4区计算机科学

Acta Informatica Pub Date : 2025-08-30 DOI: 10.1007/s00236-025-00498-8

P. Wojciechowski, K. Subramani

引用次数: 0

On integer linear programs for treewidth based on perfect elimination orderings (extended version) 基于完全消去序的树宽整数线性规划（扩展版）

IF 0.5 4区计算机科学

Acta Informatica Pub Date : 2025-08-26 DOI: 10.1007/s00236-025-00505-y

Sven Mallach

引用次数: 0

Reasoning over n-indexed sequences in SMT 在SMT中对n索引序列进行推理

IF 0.5 4区计算机科学

Acta Informatica Pub Date : 2025-08-21 DOI: 10.1007/s00236-025-00496-w

Hichem Rami Ait-El-Hara, François Bobot, Guillaume Bury

引用次数: 0

On the 3-tree core of plane graphs 关于平面图的三树核

IF 0.5 4区计算机科学

Acta Informatica Pub Date : 2025-08-18 DOI: 10.1007/s00236-025-00503-0

Debajyoti Mondal, Md. Saidur Rahman

{"title":"On the 3-tree core of plane graphs","authors":"Debajyoti Mondal, Md. Saidur Rahman","doi":"10.1007/s00236-025-00503-0","DOIUrl":"10.1007/s00236-025-00503-0","url":null,"abstract":"<div>A drawing of a graph is a geometric representation of its vertices and edges. Plane 3-trees have been well studied in graph drawing literature. For many graph drawing styles, the aesthetic qualities achieved for plane 3-trees are much better than the ones known for general plane graphs. This motivates us to investigate whether one can find a large plane 3-tree type structure in a general plane graph, and if so, whether it can be leveraged to obtain a better drawing for the graph. We thus introduce the concept of a 3-tree core H of a 3-connected plane graph G. Here, H is an edge-labeled plane 3-tree that represents G, and the distance d between H and G is the number of vertices of G that are missing in H. As an application of this concept, we consider the planar ortho-path visibility drawing, where each vertex is drawn as an orthogonal polygonal chain on an integer grid and each edge is drawn as an orthogonal line segment between the paths corresponding to its end vertices. We show that if H has a flat visibility drawing (i.e., each ortho-path is a horizontal line segment) with height k, then G has an ortho-path visibility drawing with height (O(k2^d)). In particular, if G is a planar triangulation and not too distant from a 3-tree core, i.e., (d=O(1)), then G can be drawn with height (4n/9+O(1)) by choosing an appropriate planar embedding. This bound is interesting as it is significantly smaller than the lower bound of (2n/3+O(1)) when the ortho-path visibility drawing must respect the input embedding.</div>","PeriodicalId":7189,"journal":{"name":"Acta Informatica","volume":"62 3","pages":""},"PeriodicalIF":0.5,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144861438","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}

引用次数: 0

Tracy, traces, and transducers: computable counterexamples and explanations for HyperLTL model-checking Tracy，跟踪和换能器：HyperLTL模型检查的可计算反例和解释

IF 0.5 4区计算机科学

Acta Informatica Pub Date : 2025-08-18 DOI: 10.1007/s00236-025-00499-7

Sarah Winter, Martin Zimmermann

引用次数: 0

Gray-box runtime enforcement of hyperproperties 超属性的灰盒运行时强制

IF 0.5 4区计算机科学

Acta Informatica Pub Date : 2025-08-09 DOI: 10.1007/s00236-025-00502-1

Tzu-Han Hsu, Ana Oliveira da Costa, Andrew Wintenberg, Ezio Bartocci, Borzoo Bonakdarpour

{"title":"Gray-box runtime enforcement of hyperproperties","authors":"Tzu-Han Hsu, Ana Oliveira da Costa, Andrew Wintenberg, Ezio Bartocci, Borzoo Bonakdarpour","doi":"10.1007/s00236-025-00502-1","DOIUrl":"10.1007/s00236-025-00502-1","url":null,"abstract":"<div>Enforcement of information-flow policies has been extensively studied by language-based approaches over the past few decades. In this paper, we propose an alternative, novel, general, and effective approach using enforcement of hyperproperties– a powerful formalism for expressing and reasoning about a wide range of information-flow security policies. We study black- vs. gray- vs. white-box enforcement of hyperproperties expressed by nondeterministic finite-word hyperautomata (NFH), where the enforcer has null, some, or complete information about the implementation of the system under scrutiny. Given an NFH, in order to generate a runtime enforcer, we reduce the problem to controller synthesis for hyperproperties and subsequently to the satisfiability problem for quantified Boolean formulas (QBFs). The resulting enforcers are transferable with low-overhead. We conduct a rich set of case studies, including information-flow control for JavaScript code, as well as synthesizing obfuscators for control plants.</div>","PeriodicalId":7189,"journal":{"name":"Acta Informatica","volume":"62 3","pages":""},"PeriodicalIF":0.5,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00236-025-00502-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145163654","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}

引用次数: 0

Preserving hyperproperties of programs using primitives with consensus number 2 保留使用共识数为2的原语的程序的超属性

IF 0.5 4区计算机科学

Acta Informatica Pub Date : 2025-08-06 DOI: 10.1007/s00236-025-00500-3

Hagit Attiya, Armando Castañeda, Constantin Enea

{"title":"Preserving hyperproperties of programs using primitives with consensus number 2","authors":"Hagit Attiya, Armando Castañeda, Constantin Enea","doi":"10.1007/s00236-025-00500-3","DOIUrl":"10.1007/s00236-025-00500-3","url":null,"abstract":"<div>When a concrete concurrent object refines another, more abstract object, the correctness of a program employing the concrete object can be verified by considering its behaviors when using the more abstract object. This approach is sound for trace properties of the program, but not for hyperproperties, including many security properties and probability distributions of events. We define strong observational refinement, a strengthening of refinement that preserves hypersafety properties, and prove that it is equivalent to the existence of forward simulations. We show that strong observational refinement generalizes strong linearizability, a restriction of linearizability, the prevalent consistency condition for implementing concurrent objects. Our results imply that strong linearizability is also equivalent to existence of forward simulations, and show that strongly linearizable implementations can be composed both horizontally and vertically. This paper also investigates whether there are wait-free strongly-linearizable implementations from realistic primitives such as test&set or fetch&add, whose consensus number is 2. We show that many objects with consensus number 1 have wait-free strongly-linearizable implementations from fetch&add. We also show that several objects with consensus number 2 have wait-free or lock-free implementations from other objects with consensus number 2. In contrast, we prove that even when fetch&add, swap and test&set primitives are used, some objects with consensus number 2 do not have lock-free strongly-linearizable implementations. This includes queues and stacks, and relaxed variants thereof.</div>","PeriodicalId":7189,"journal":{"name":"Acta Informatica","volume":"62 3","pages":""},"PeriodicalIF":0.5,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00236-025-00500-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145162477","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}

引用次数: 0

Novel tree-search method for synthesizing SMT strategies 一种新的SMT策略合成树搜索方法

IF 0.5 4区计算机科学

Acta Informatica Pub Date : 2025-08-04 DOI: 10.1007/s00236-025-00495-x

Zhengyang John Lu, Joel Day, Piyush Jha, Paul Sarnighausen-Cahn, Stefan Siemer, Florin Manea, Vijay Ganesh

{"title":"Novel tree-search method for synthesizing SMT strategies","authors":"Zhengyang John Lu, Joel Day, Piyush Jha, Paul Sarnighausen-Cahn, Stefan Siemer, Florin Manea, Vijay Ganesh","doi":"10.1007/s00236-025-00495-x","DOIUrl":"10.1007/s00236-025-00495-x","url":null,"abstract":"<div>Modern SMT solvers, such as Z3, allow solver users to customize strategies to improve performance on their specific use cases. However, handcrafting an optimized strategy for a specific class of SMT instances remains a complex and demanding task for both solver developers and users alike. In this paper, we address the problem of automated SMT strategy synthesis via a novel method based on Monte-Carlo Tree Search (MCTS). We formulate strategy synthesis as a sequential decision-making process, where the search tree corresponds to the strategy space. Subsequently, we employ MCTS to navigate this vast search space. Compared to the conventional MCTS, we introduce two heuristics—layered and staged search—that enable our method to identify effective strategies with lower costs. We implement our method, dubbed Z3alpha, upon the Z3 SMT solver. Our experiments demonstrate that Z3alpha outperforms the default Z3 solver and the state-of-the-art synthesis tool Fastsmt on the majority of the evaluated benchmark sets, while producing more interpretable strategies than FastSMT. At SMT-COMP’24, among the 16 participating logics, Z3alpha improved upon the default Z3 in 12 cases and helped solve hundreds more instances in QF_NIA and QF_NRA, winning their respective divisions.</div>","PeriodicalId":7189,"journal":{"name":"Acta Informatica","volume":"62 3","pages":""},"PeriodicalIF":0.5,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00236-025-00495-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145161738","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}

引用次数: 0