样式: 排序: IF: - GO 导出 标记为已读
-
Monitoring the edges of a graph using distances with given girth J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2024-03-06 Chenxu Yang, Gang Yang, Sun-Yuan Hsieh, Yaping Mao, Ralf Klasing
For a vertex set and an edge of a graph , if there exists a vertex such that or , then is monitored by . A vertex set of the graph is a (DEM set, for short) if all edges are monitored by some vertices of . The of a graph is defined as the minimum cardinality of a DEM set of . In this paper, we prove that for a connected graph , which is not a tree, of order , where ( for short) is the length of a shortest
-
Deep kernelization for the Tree Bisection and Reconnection (TBR) distance in phylogenetics J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2024-01-26 Steven Kelk, Simone Linz, Ruben Meuwese
We describe a kernel of size for the NP-hard problem of computing the Tree Bisection and Reconnection (TBR) distance between two unrooted binary phylogenetic trees. To achieve this, we extend the existing portfolio of reduction rules with three new reduction rules. Two of these are based on the idea of topologically transforming the trees in a distance-preserving way in order to guarantee execution
-
SAT backdoors: Depth beats size J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2024-01-19 Jan Dreier, Sebastian Ordyniak, Stefan Szeider
For several decades, much effort has been put into identifying classes of CNF formulas whose satisfiability can be decided in polynomial time. Classic results are the linear-time tractability of Horn formulas (Aspvall, Plass, and Tarjan, 1979) and Krom (i.e., 2CNF) formulas (Dowling and Gallier, 1984). Backdoors, introduced by Williams, Gomes and Selman (2003), gradually extend such a tractable class
-
The maximal coordination principle in regulatory Boolean networks J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2024-01-17 A, l, e, x, i, s, , P, o, i, n, d, r, o, n
We introduce a coordination index in regulatory Boolean networks and we expose the maximal coordination principle (MCP), according to which a cohesive society reaches the dynamics characterized by the highest coordination index. Based on simple theoretical examples, we show that the MCP can be used to infer the influence graph from opinion dynamics/gene expressions. We provide some algorithms to apply
-
-
On coresets for fair clustering in metric and Euclidean spaces and their applications J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2024-01-11 Sayan Bandyapadhyay, Fedor V. Fomin, Kirill Simonov
Fair clustering is a constrained clustering problem where we need to partition a set of colored points. The fraction of points of each color in every cluster should be more or less equal to the fraction of points of this color in the dataset. The problem was recently introduced by Chierichetti et al. (2017) . We propose a new construction of coresets for fair clustering for Euclidean and general metrics
-
Blackout-tolerant temporal spanners J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-12-04 Davide Bilò, Gianlorenzo D'Angelo, Luciano Gualà, Stefano Leucci, Mirko Rossi
We introduce the notions of blackout-tolerant temporal α-spanner of a temporal graph G which is a subgraph of G that preserves the distances between pairs of vertices of interest in G up to a multiplicative factor of α, even when the graph edges at a single time-instant become unavailable. In particular, we consider the single-source, single-pair, and all-pairs cases and, for each case we look at three
-
PAC learning halfspaces in non-interactive local differential privacy model with public unlabeled data J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-12-06 Jinyan Su, Jinhui Xu, Di Wang
In this paper, we study the problem of PAC learning halfspaces in the non-interactive local differential privacy model (NLDP). To breach the barrier of exponential sample complexity, previous results studied a relaxed setting where the server has access to some additional public but unlabeled data. We continue in this direction. Specifically, we consider the problem under the standard setting instead
-
Special Issue on the 1st Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2022) J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-12-06 James Aspnes, Othon Michail
Abstract not available
-
Lifting query complexity to time-space complexity for two-way finite automata J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-12-04 Shenggen Zheng, Yaqiao Li, Minghua Pan, Jozef Gruska, Lvzhou Li
Time-space tradeoff has been studied in a variety of models, such as Turing machines, branching programs, and finite automata, etc. While communication complexity as a technique has been applied to study finite automata, it seems it has not been used to study time-space tradeoffs of finite automata. We design a new technique showing that separations of query complexity can be lifted, via communication
-
Corrigendum to “Prediction, learning, uniform convergence, and scale-sensitive dimensions” [J. Comput. Syst. Sci. 56 (2) (1998) 174–190] J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-11-09 Peter L. Bartlett, Philip M. Long
Abstract not available
-
Solving problems on generalized convex graphs via mim-width J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-11-07 Flavia Bonomo-Braberman, Nick Brettell, Andrea Munaro, Daniël Paulusma
A bipartite graph G=(A,B,E) is H-convex for some family of graphs H if there exists a graph H∈H with V(H)=A such that the neighbours in A of each b∈B induce a connected subgraph of H. Many NP-complete problems are polynomial-time solvable for H-convex graphs when H is the set of paths. The underlying reason is that the class has bounded mim-width. We extend this result to families of H-convex graphs
-
Bounded incentives in manipulating the probabilistic serial rule J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-10-28 Haoqiang Huang, Zihe Wang, Zhide Wei, Jie Zhang
The Probabilistic Serial mechanism is valued for its fairness and efficiency in addressing the random assignment problem. However, it lacks truthfulness, meaning it works well only when agents' stated preferences match their true ones. Significant utility gains from strategic actions may lead self-interested agents to manipulate the mechanism, undermining its practical adoption. To gauge the potential
-
Performance modeling and analysis for randomly walking mobile users with Markov chains J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-10-18 Keqin Li
We treat user equipments (UEs) and mobile edge clouds (MECs) as M/G/1 queueing systems, which are the most suitable, powerful, and manageable models. We propose a computation offloading strategy which can satisfy all UEs served by an MEC and develop an efficient method to find such a strategy. We use discrete-time Markov chains, continuous-time Markov chains, and semi-Markov processes to characterize
-
-
Orienting undirected phylogenetic networks J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-10-04 Katharina T. Huber, Leo van Iersel, Remie Janssen, Mark Jones, Vincent Moulton, Yukihiro Murakami, Charles Semple
This paper studies the relationship between undirected (unrooted) and directed (rooted) phylogenetic networks. We describe a polynomial-time algorithm for deciding whether an undirected nonbinary phylogenetic network, given the locations of the root and reticulation vertices, can be oriented as a directed nonbinary phylogenetic network. Moreover, we characterize when this is possible and show that
-
Fast and succinct population protocols for Presburger arithmetic J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-09-29 Philipp Czerner, Roland Guttenberg, Martin Helfrich, Javier Esparza
In their 2006 seminal paper in Distributed Computing, Angluin et al. present a construction that, given any Presburger predicate, outputs a leaderless population protocol that decides the predicate. The protocol for a predicate of size m runs in O(m⋅n2logn) expected number of interactions, which is almost optimal in n, the number of interacting agents. However, the number of states is exponential
-
A near-linear kernel for bounded-state parsimony distance J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-09-26 Elise Deen, Leo van Iersel, Remie Janssen, Mark Jones, Yukihiro Murakami, Norbert Zeh
The maximum parsimony distance dMP(T1,T2) and the bounded-state maximum parsimony distance dMPt(T1,T2) measure the difference between two phylogenetic trees T1,T2 in terms of the maximum difference between their parsimony scores for any character (with t a bound on the number of states in the character, in the case of dMPt(T1,T2)). While computing dMP(T1,T2) was previously shown to be fixed-parameter
-
The satisfiability problem for a quantitative fragment of PCTL J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-09-15 Miroslav Chodil, Antonín Kučera
We propose a generic method for proving the decidability of the finite satisfiability problem for PCTL fragments and demonstrate its applicability in several non-trivial examples.
-
Serial and parallel kernelization of Multiple Hitting Set parameterized by the Dilworth number, implemented on the GPU J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-09-12 René van Bevern, Artem M. Kirilin, Daniel A. Skachkov, Pavel V. Smirnov, Oxana Yu. Tsidulko
The NP-hard Multiple Hitting Set problem is the problem of finding a minimum-cardinality set intersecting each of the sets in a given input collection a given number of times. Generalizing a well-known data reduction algorithm due to Weihe, we show a problem kernel for Multiple Hitting Set parameterized by the Dilworth number, a graph parameter introduced by Foldes and Hammer in 1978 yet seemingly
-
Wireless IoT sensors data collection reward maximization by leveraging multiple energy- and storage-constrained UAVs J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-09-01 Francesco Betti Sorbelli, Alfredo Navarra, Lorenzo Palazzetti, Cristina M. Pinotti, Giuseppe Prencipe
We consider Internet of Things (IoT) sensors deployed inside an area to be monitored. Drones can be used to collect the data from the sensors, but they are constrained in energy and storage. Therefore, all drones need to select a subset of sensors whose data are the most relevant to be acquired, modeled by assigning a reward. We present an optimization problem called Multiple-drone Data-collection
-
Mengerian graphs: Characterization and recognition J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-08-29 Allen Ibiapina, Ana Silva
A temporal graph G is a pair (G,λ) where G is a graph and λ is a function on the edges of G describing when each edge is active. Temporal connectivity then concerns only paths that respect the flow of time. In this context, it is known that Menger's Theorem does not hold. In a seminal paper, Kempe, Kleinberg and Kumar (STOC'2000) defined a graph to be Mengerian if equality holds for every time-function
-
Perpetual maintenance of machines with different urgency requirements J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-08-29 Leszek Gąsieniec, Tomasz Jurdziński, Ralf Klasing, Christos Levcopoulos, Andrzej Lingas, Jie Min, Tomasz Radzik
A garden is populated by n bamboos, each with its own daily growth rate. The Bamboo Garden Trimming Problem (BGT) is to design for a robotic gardener a perpetual schedule of cutting bamboos to keep the elevation of the garden as low as possible. The frequency of cutting is constrained by the time needed to move from one bamboo to the next, which is one day in Discrete BGT and is defined by the distance
-
-
On the Complexity of the Storyplan Problem J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-08-11 Carla Binucci, Emilio Di Giacomo, William J. Lenhart, Giuseppe Liotta, Fabrizio Montecchiani, Martin Nöllenburg, Antonios Symvonis
We study the problem of representing a graph as a storyplan, a recently introduced model for dynamic graph visualization. It is based on a sequence of frames, each showing a subset of vertices and a planar drawing of their induced subgraphs, where vertices appear and disappear over time. Namely, in the StoryPlan problem, we are given a graph and we want to decide whether there exists a total vertex
-
Restrained medium access control on adversarial shared channels J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-07-07 Elijah Hradovich, Marek Klonowski, Dariusz R. Kowalski
We study the fundamental problem of utilization of the channel shared by stations competing to transmit packets on the channel. In their turn, packets are continuously injected into stations' queues by an adversary at a rate at most ρ packets per round. The aim of the distributed medium access control algorithms is to successfully transmit packets and maintain system stability (bounded queues). We
-
The possible winner with uncertain weights problem J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-06-28 Dorothea Baumeister, Marc Neveling, Magnus Roos, Jörg Rothe, Lena Schend, Robin Weishaupt, Lirong Xia
The original possible winner problem consists of an unweighted election with partial preferences and a distinguished candidate c and asks whether the preferences can be extended to total ones such that c wins the given election. We introduce a novel variant of this problem: possible winner with uncertain weights. In this variant, for a given weighted election, not some of the preferences but some of
-
Building squares with optimal state complexity in restricted active self-assembly J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-06-20 Robert M. Alaniz, David Caballero, Sonya C. Cirlos, Timothy Gomez, Elise Grizzell, Andrew Rodriguez, Robert Schweller, Armando Tenorio, Tim Wylie
Tile Automata is a recently defined model of self-assembly that borrows many concepts from cellular automata to create active self-assembling systems where changes may be occurring within an assembly without requiring attachment. This model has been shown to be powerful even with limited assembly size, but many fundamental questions have yet to be explored. Here, we study the state complexity of assembling
-
Deletion to scattered graph classes I - Case of finite number of graph classes J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-06-15 Ashwin Jacob, Jari J.H. de Kroon, Diptapriyo Majumdar, Venkatesh Raman
Graph-deletion problems involve deleting a small number of vertices so that the resulting graph belong to a given hereditary graph class. We initiate a study of a natural variation of the problem of deletion to scattered graph classes. We want to delete at most k vertices so that each connected component of the resulting graph belongs to one of the constant number of graph classes. As our main result
-
-
Finding k-secluded trees faster J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-06-05 Huib Donkers, Bart M.P. Jansen, Jari J.H. de Kroon
We revisit the k-Secluded Tree problem. Given a vertex-weighted undirected graph G, its objective is to find a maximum-weight induced subtree T whose open neighborhood has size at most k. We present a fixed-parameter tractable algorithm that solves the problem in time 2O(klogk)⋅nO(1), improving on a double-exponential running time from earlier work by Golovach, Heggernes, Lima, and Montealegre. Starting
-
Balanced allocation on hypergraphs J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-05-30 Catherine Greenhill, Bernard Mans, Ali Pourmiri
We consider a variation of balls-into-bins which randomly allocates m balls into n bins. Following Godfrey's model (SODA, 2008), we assume that each ball t, 1⩽t⩽m, comes with a hypergraph H(t)={B1,B2,…,Bst}, and each edge B∈H(t) contains at least a logarithmic number of bins. Given d⩾2, our d-choice algorithm chooses an edge B∈H(t), uniformly at random, and then chooses a set D of d random bins from
-
Weighted online search J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-05-30 Spyros Angelopoulos, Konstantinos Panagiotou
We study the general setting of weighted search in which a number of weighted targets are hidden in a star-like environment, and a mobile searcher must locate a subset of targets with aggregate weight at least a given value W. The cost of the strategy is the distance traversed by the searcher, and its performance is measured by the worst-case ratio of the cost incurred by the searcher over the cost
-
Interaction graphs of isomorphic automata networks I: Complete digraph and minimum in-degree J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-05-25 Florian Bridoux, Kévin Perrot, Aymeric Picard Marchetto, Adrien Richard
An automata network with n components over a finite alphabet Q of size q is a discrete dynamical system described by the successive iterations of a function f:Qn→Qn. In most applications, the main parameter is the interaction graph of f: the digraph with vertex set [n] that contains an arc from j to i if fi depends on input j. What can be said on the set G(f) of the interaction graphs of the automata
-
Detours in directed graphs J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-05-22 Fedor V. Fomin, Petr A. Golovach, William Lochet, Danil Sagunov, Saket Saurabh, Kirill Simonov
We study two “above guarantee” versions of the classical Longest Path problem on undirected and directed graphs and obtain the following results. In the first variant of Longest Path that we study, called Longest Detour, the task is to decide whether a graph has an (s,t)-path of length at least distG(s,t)+k. Bezáková et al. [7] proved that on undirected graphs the problem is fixed-parameter tractable
-
-
Linear-time 2-party secure merge from additively homomorphic encryption J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-05-11 Brett Hemenway Falk, Rohit Nema, Rafail Ostrovsky
We present a linear-time, space and communication data-oblivious algorithm for securely merging two private, sorted lists into a single sorted, secret-shared list in the two party setting. Although merging two sorted lists can be done insecurely in linear time, previous secure merge algorithms all require super-linear time and communication. A key feature of our construction is a novel method to obliviously
-
Space characterizations of complexity measures and size-space trade-offs in propositional proof systems J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-05-04 Theodoros Papamakarios, Alexander Razborov
-
Computing maximum matchings in temporal graphs J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-05-04 George B. Mertzios, Hendrik Molter, Rolf Niedermeier, Viktor Zamaraev, Philipp Zschoche
Temporal graphs are graphs whose topology is subject to discrete changes over time. Given a static underlying graph G, a temporal graph is represented by assigning a set of integer time-labels to every edge e of G, indicating the discrete time steps at which e is active. We introduce and study the complexity of a natural temporal extension of the classical graph problem Maximum Matching, taking into
-
Almost optimal query algorithm for hitting set using a subset query J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-04-25 Arijit Bishnu, Arijit Ghosh, Sudeshna Kolay, Gopinath Mishra, Saket Saurabh
In this paper, we focus on Hitting-Set, a fundamental problem in combinatorial optimization, through the lens of sublinear time algorithms. Given access to the hypergraph through a subset query oracle in the query model, we give sublinear time algorithms for Hitting-Set with almost tight parameterized query complexity. In parameterized query complexity, we estimate the number of queries to the oracle
-
Synchronizing Boolean networks asynchronously J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-04-18 Julio Aracena, Adrien Richard, Lilian Salinas
The asynchronous automaton of a Boolean network f:{0,1}n→{0,1}n, considered in many applications, is the finite deterministic automaton where the set of states is {0,1}n, the alphabet is [n], and the action of letter i on a state x consists in either switching the ith component if fi(x)≠xi or doing nothing otherwise. In this paper, we ask for the existence of synchronizing words for this automaton
-
Deletion to scattered graph classes II - improved FPT algorithms for deletion to pairs of graph classes J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-04-17 Ashwin Jacob, Diptapriyo Majumdar, Venkatesh Raman
The problem of deletion of vertices to a hereditary graph class is a well-studied problem in parameterized complexity. Recently, a natural extension of the problem was initiated where we are given a finite set of hereditary graph classes and we determine whether k vertices can be deleted from a given graph so that the connected components of the resulting graph belong to one of the given hereditary
-
Controlling entity integrity with key sets J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-04-14 Miika Hannula, Xinyi Li, Sebastian Link
Codd's rule of entity integrity stipulates that every table has a primary key. Key sets can control entity integrity when primary keys do not exist. While key set validation is quadratic, update maintenance for unary key sets is efficient when incomplete values only occur in few key columns. We establish a binary axiomatization for the implication problem, and prove its coNP-completeness. However,
-
Markov chains and unambiguous automata J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-04-13 Christel Baier, Stefan Kiefer, Joachim Klein, David Müller, James Worrell
Unambiguous automata are nondeterministic automata in which every word has at most one accepting run. In this paper we give a polynomial-time algorithm for model checking discrete-time Markov chains against ω-regular specifications represented as unambiguous automata. We furthermore show that the complexity of this model checking problem lies in NC: the subclass of P comprising those problems solvable
-
Galactic token sliding J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-04-13 Valentin Bartier, Nicolas Bousquet, Amer E. Mouawad
Given a graph G and two independent sets Is and It of size k, the Independent Set Reconfiguration problem asks whether there exists a sequence of independent sets that transforms Is to It such that each independent set is obtained from the previous one using a so-called reconfiguration step. Viewing each independent set as a collection of k tokens placed on the vertices of a graph G, the two most studied
-
Parameterized complexity of categorical clustering with size constraints J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-04-13 Fedor V. Fomin, Petr A. Golovach, Nidhi Purohit
In the Categorical Clustering problem, we are given a set of vectors (matrix) A={a1,…,an} over Σm, where Σ is a finite alphabet, and integers k and B. The task is to partition A into k clusters such that the median objective of the clustering in the Hamming norm is at most B. Fomin, Golovach, and Panolan [ICALP 2018] proved that the problem is fixed-parameter tractable for the binary case Σ={0,1}.
-
Algebraic characterizations and block product decompositions for first order logic and its infinitary quantifier extensions over countable words J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-04-12 Bharat Adsul, Saptarshi Sarkar, A.V. Sreejith
We contribute to the refined understanding of language-logic-algebra interplay in a recent algebraic framework over countable words. Algebraic characterizations of the one variable fragment of FO as well as the boolean closure of the existential fragment of FO are established. We develop a seamless integration of the block product operation in the countable setting, and generalize well-known decompositional
-
From symmetry to asymmetry: Generalizing TSP approximations by parametrization J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-04-12 Lukas Behrendt, Katrin Casel, Tobias Friedrich, J.A. Gregor Lagodzinski, Alexander Löser, Marcus Wilhelm
We generalize the tree doubling and Christofides algorithm to parameterized approximations for ATSP (constant factor approximations that invest more runtime with respect to a chosen parameter). The parameters we consider are upper bounded by the number of asymmetric distances, which yields algorithms to efficiently compute good approximations for moderately asymmetric TSP instances. As generalization
-
Addition machines, automatic functions and open problems of Floyd and Knuth J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-04-12 Sanjay Jain, Xiaodong Jia, Ammar Fathin Sabili, Frank Stephan
Floyd and Knuth investigated in 1990 register machines which can add, subtract and compare integers as primitive operations. They asked whether their current bound on the number of registers for multiplying and dividing fast (running in time linear in the size of the input) can be improved and whether one can output fast the powers of two summing up to a positive integer in subquadratic time. Both
-
-
Reducing the vertex cover number via edge contractions J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-03-23 Paloma T. Lima, Vinicius F. dos Santos, Ignasi Sau, Uéverton S. Souza, Prafullkumar Tale
Given a graph G on n vertices and two integers k and d, the Contraction(vc) problem asks whether one can contract at most k edges to reduce the vertex cover number of G by at least d. Recently, Lima et al. [JCSS 2021] proved that Contraction(vc) admits an XP algorithm running in time f(d)⋅nO(d). They asked whether this problem is FPT under this parameterization. In this article, we prove that: (i)
-
Complexity of verification in self-assembly with prebuilt assemblies J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-03-21 David Caballero, Timothy Gomez, Robert Schweller, Tim Wylie
We analyze the complexity of two fundamental verification problems within a generalization of the two-handed tile self-assembly model (2HAM) where initial system assemblies are not restricted to be singleton tiles, but may be larger prebuilt assemblies. Within this model we consider the producibility problem, which asks if a given tile system builds, or produces, a given assembly, and the unique assembly
-
Parameterized complexity of graph planarity with restricted cyclic orders J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-03-13 Giuseppe Liotta, Ignaz Rutter, Alessandra Tappini
We study the complexity of testing whether a biconnected graph G=(V,E) is planar with the constraint that some cyclic orders of the edges incident to its vertices are allowed while some others are forbidden. The allowed cyclic orders are described by associating every vertex v of G with a set D(v) of FPQ-trees. Let tw be the treewidth of G and let Dmax be the maximum number of FPQ-trees per vertex
-
Grid recognition: Classical and parameterized computational perspectives J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-03-17 Siddharth Gupta, Guy Sa'ar, Meirav Zehavi
Over the past few decades, a large body of works studied the (in)tractability of various computational problems on grid graphs, which often yield substantially faster algorithms than general graphs. Unfortunately, the recognition of a grid graph is hard—it was shown to be NP-hard already in 1987. In this paper, we provide several positive results in this regard in the framework of parameterized complexity
-
How heavy independent sets help to find arborescences with many leaves in DAGs J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-03-13 Cristina G. Fernandes, Carla N. Lintzmayer
Trees with many leaves have applications for broadcasting a message to all recipients simultaneously. Internal nodes of a broadcasting tree require more expensive technology to forward the messages received. We address a problem that captures the main goal: finding spanning trees with few internal nodes in a given network. The Maximum Leaf Spanning Arborescence problem consists of, given a directed
-
Complexity of word problems for HNN-extensions J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-03-09 Markus Lohrey
The computational complexity of the word problem in HNN-extension of groups is studied. HNN-extension is a fundamental construction in combinatorial group theory. It is shown that the word problem for an ascending HNN-extension of a group H is logspace reducible to the so-called compressed word problem for H. The main result of the paper states that the word problem for an HNN-extension of a hyperbolic
-
The 2CNF Boolean formula satisfiability problem and the linear space hypothesis J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-03-09 Tomoyuki Yamakami
We aim at investigating the solvability/insolvability of nondeterministic logarithmic-space (NL) decision, search, and optimization problems parameterized by natural size parameters using simultaneously polynomial time and sub-linear space. We are particularly focused on 2SAT3—a restricted variant of the 2CNF Boolean (propositional) formula satisfiability problem in which each variable of a given 2CNF
-
Bankrupting Sybil despite churn J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-02-27 Diksha Gupta, Jared Saia, Maxwell Young
A Sybil attack occurs when an adversary controls multiple system identifiers (IDs). Limiting the number of Sybil (bad) IDs to a minority is critical for tolerating malicious behavior. A popular tool for enforcing a bad minority is resource burning (RB): the verifiable consumption of a network resource. Unfortunately, typical RB defenses require non-Sybil (good) IDs to consume at least as many resources
-
On the exact amount of missing information that makes finding possible winners hard J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-02-20 Palash Dey, Neeldhara Misra
In the possible winner problem, we need to compute if a set of partial votes can be completed such that a given candidate wins the election under some specific voting rule. In this paper, we determine the smallest number of undetermined pairs per partial vote for which the Possible Winner problem is NP-complete. In particular, we find the exact values of t for which the Possible Winner problem transitions
-
Bipartite 3-regular counting problems with mixed signs J. Comput. Syst. Sci. (IF 1.1) Pub Date : 2023-02-14 Jin-Yi Cai, Austen Z. Fan, Yin Liu
We prove a complexity dichotomy for a class of counting problems expressible as bipartite 3-regular Holant problems. These are also counting CSP problems where every constraint has arity 3 and every variable is read-thrice. For every problem of the form Holant(f|=3), where f is any integer (or equivalently, rational)-valued ternary symmetric constraint function on Boolean variables, we prove that it