Showing papers in "Journal of Computer and System Sciences in 2021"
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TL;DR: In this article, it was shown that TEXP is NP-hard to approximate TEXP with ratio O( n 1 − e ) for every e > 0 and presented several solutions for special graph classes.
34 citations
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TL;DR: In this article, the problem of determining an ordering of edges that minimises the maximum number of vertices reachable from any single starting vertex is investigated. But the problem is NP-hard.
25 citations
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TL;DR: A new complexity class is defined, called BU, which captures all problems that can be reduced to solving an instance of the Borsuk-Ulam problem exactly, and that LinearBU = PPA, where LinearBU is the subclass of BU in which the BORSuk- Ulam instance is specified by a linear arithmetic circuit.
23 citations
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TL;DR: The results on these new End-of-Line variants are of independent interest and provide new tools for showing membership in PPAD, and provide the first full proof of PPAD-completeness for the Imbalance problem defined by Beame et al. in 1998.
18 citations
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TL;DR: This paper introduces two natural deletion problems for temporal graphs (for deletion of edges and of edge availabilities, respectively) and provides positive and negative results on their computational complexity, both in the traditional and the parameterized sense, subject to various natural parameters.
18 citations
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TL;DR: A systematic study of the computational complexity of the problem of exploring a temporal graph when the underlying graph is a star, depending on the number k of time points where each edge can be present in the graph.
15 citations
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TL;DR: This work introduces the first grammar-compressed index that uses $O(G\lg n)$ bits and can find the occurrences of patterns $P[1..m]$ in time $O((m^2+occ)\lg G)$.
15 citations
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TL;DR: The complexity of reachability decision problems for parametric Markov decision processes (pMDPs) is presented, and all known lower bounds are improved, and ETR-completeness results for distinct variants of this problem are provided.
9 citations
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TL;DR: In this article, it was shown that if G is a complete graph, then one can always find a temporal spanner with O( n log n ) edges.
9 citations
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TL;DR: A dichotomy in data complexity for the complete space of FDs is established: when the FD set has, up to equivalence, what the authors call a “left-hand-side chain,” the repairs can be counted in polynomial time; otherwise, the problem is ♯ P -complete.
9 citations
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TL;DR: A thorough investigation of the computational complexity of this temporal coloring problem is presented, and strong computational hardness results are proved, complemented by efficient exact and approximation algorithms.
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TL;DR: It is shown that hyperedge-replacement grammars can generate NP-complete graph languages even under seemingly harsh restrictions and the parsing problem is difficult even in the n graph languages.
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TL;DR: This paper presents the first non-trivial worst-case upper bounds for the k-CPM problem and shows an \(\mathcal {O}(nk)\)-time algorithm and an extended way a technique that was very recently developed for thek-mismatch problem.
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TL;DR: For two packages, it is shown that the problem of minimizing the maximum or the sum of the delivery times is NP-hard for arbitrary agent velocities, but polynomial-time solvable for agents with equal velocity.
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TL;DR: The presented proof for bisimulation equivalence of first-order grammars is an alternative proof for a result by Senizergues (1998, 2005) that subsumes his affirmative solution of the famous decidability question for deterministic pushdown automata.
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TL;DR: Using a simple potential function argument, it is shown that a d-approximate pure Nash equilibrium of cost at most ( d + 1 ) / ( d - δ ) times the cost of an optimal state always exists, for every δ ∈ [ 0, 1 ].
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TL;DR: This paper proposes the first unidirectional infinite-use proxy re-signature scheme and identity-based unid directional one-use and multi-use proxies with private re-Signature keys based on lattice and proves that they are secure in the random oracle model.
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TL;DR: The upper and lower bounds on m λ ( G ) are given, which completely determine the exact values of m κ and S λ for vertex transitive graphs.
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TL;DR: In this paper, it was shown that the problem of computing the maximum parsimony distance between two unrooted phylogenetic trees is fixed parameter tractable, i.e., after applying certain reduction rules the resulting instance has size that is bounded by a linear function of the distance.
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TL;DR: This work proposes efficient probabilistic verification procedures for popular signature schemes in which the error probability of a verifier decreases exponentially with the verifier running time and presents a general practical method that makes use of efficient error-correcting codes for signature schemes for which verification involves a matrix/vector multiplication.
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TL;DR: It is proved that reachability relations of tpda are expressible in linear arithmetic, a rich logic generalising Presburger arithmetic and rational arithmetic.
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TL;DR: In this paper, the authors study three natural problems concerning words giving certain preimages. And they conclude with a summary of the complexities in all combinations of the cases, including variants where the length of the word is upper bounded, where the size of the given subset is restricted, and where the automaton is strongly connected, synchronizing, or binary.
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TL;DR: It is proved that, under the minimal assumption on the dynamics, temporal connectivity, the number of agents sufficient to perform exploration of dynamic graphs of arbitrary unknown topology depends on a parameter the authors call evanescence of the graph, and this number is tight.
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TL;DR: This work designs a polynomial-time 0.4209-additive approximation algorithm for the modularity maximization problem, which improves the current best additive approximation error and demonstrates that the proposed algorithm obtains a nearly-optimal solution for any instance with a high modularity value.
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TL;DR: This paper complements the known negative results by showing that for p = 0 and p = ∞, k -Clustering is W [ 1 ] -hard when parameterized by D, and discovers a tractability island of k - Clustering.
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TL;DR: An analytical approach is taken in the sense that the quality of service and the price of service as well as the revenue, cost, and profit of a cloud service provider (CSP) can all be quantitatively available based on well established analytical models.
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TL;DR: In this article, a framework for applying treewidth-based dynamic programming on graphs with hybrid structure is proposed, where parts of the graph that do not belong to a pre-specified tractable graph class are considered.
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TL;DR: It is shown that the problem of finding an unknown odd-degree vertex or a local optimum vertex on a graph with potential is polynomially equivalent to EndOfPotentialLine if the maximum degree is at most three, however, even if themaximum degree is 4, such a problem is PPA ∩ PLS -complete.
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TL;DR: In this paper, the authors extend the transition methodology by optimizing the costs of transition and analyzing the behavior using multiple operator placement mechanisms, which can inflict overhead on the performance if operated uncoordinatedly.
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TL;DR: A star-free version of propositional dynamic logic (PDL) with loop and converse is introduced and it is shown that first-order logic over MSCs has the three-variable property.