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  • On Tseitin Formulas, Read-Once Branching Programs and Treewidth
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-10-09
    Ludmila Glinskih, Dmitry Itsykson

    We show that any nondeterministic read-once branching program that decides a satisfiable Tseitin formula based on an n × n grid graph has size at least 2Ω(n). Then using the Excluded Grid Theorem by Robertson and Seymour we show that for an arbitrary graph G(V, E) any nondeterministic read-once branching program that computes a satisfiable Tseitin formula based on G has size at least \(2^{\Omega (\text

    更新日期:2020-10-11
  • On the Expressive Power of Linear Algebra on Graphs
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-10-04
    Floris Geerts

    There is a long tradition in understanding graphs by investigating their adjacency matrices by means of linear algebra. Similarly, logic-based graph query languages are commonly used to explore graph properties. In this paper, we bridge these two approaches by regarding linear algebra as a graph query language. More specifically, we consider MATLANG, a matrix query language recently introduced, in

    更新日期:2020-10-04
  • The Containment Problem for Unambiguous Register Automata and Unambiguous Timed Automata
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-09-15
    Antoine Mottet, Karin Quaas

    We investigate the complexity of the containment problem “Does \(L(\mathcal {A})\subseteq L({\mathscr{B}})\) hold?” for register automata and timed automata, where \({\mathscr{B}}\) is assumed to be unambiguous and \(\mathcal {A}\) is arbitrary. We prove that the problem is decidable in the case of register automata over \((\mathbb N,=)\), in the case of register automata over \((\mathbb Q,<)\) when

    更新日期:2020-09-15
  • The Non-hardness of Approximating Circuit Size
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-09-12
    Eric Allender, Rahul Ilango, Neekon Vafa

    The Minimum Circuit Size Problem (MCSP) has been the focus of intense study recently; MCSP is hard for SZK under rather powerful reductions (Allender and Das Inf. Comput. 256, 2–8, 2017), and is provably not hard under “local” reductions computable in TIME(n0.49) (Murray and Williams Theory Comput. 13(1), 1–22, 2017). The question of whether MCSP is NP-hard (or indeed, hard even for small subclasses

    更新日期:2020-09-13
  • Characterizing Tractability of Simple Well-Designed Pattern Trees with Projection
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-09-10
    Stefan Mengel, Sebastian Skritek

    We study the complexity of evaluating well-designed pattern trees, a query language extending conjunctive queries with the possibility to define parts of the query to be optional. This possibility of optional parts is important for obtaining meaningful results over incomplete data sources as it is common in semantic web settings. Recently, a structural characterization of the classes of well-designed

    更新日期:2020-09-10
  • Analyzing Clustering and Partitioning Problems in Selected VLSI Models
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-08-22
    Z. Donovan, K. Subramani, V. Mkrtchyan

    As the modern integrated circuit continues to grow in complexity, the design of very large-scale integrated (VLSI) circuits involves massive teams employing state-of-the-art computer-aided design (CAD) tools. An old yet significant CAD problem for VLSI circuits is physical design automation. In physical design automation, we need to compute the best physical layout of millions to billions of circuit

    更新日期:2020-08-22
  • On the Relation Between Structured d -DNNFs and SDDs
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-08-17
    Beate Bollig, Martin Farenholtz

    Structured d-DNNFs and SDDs are restricted negation normal form circuits used in knowledge compilation as target languages into which propositional theories are compiled. Structuredness is imposed by so-called vtrees. By definition SDDs are restricted structured d-DNNFs. Beame and Liew (2015) as well as Bova and Szeider (2017) mentioned the question whether structured d-DNNFs are really more general

    更新日期:2020-08-18
  • Semi-Oblivious Chase Termination: The Sticky Case
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-08-17
    Marco Calautti, Andreas Pieris

    The chase procedure is a fundamental algorithmic tool in database theory with a variety of applications. A key problem concerning the chase procedure is all-instances termination: for a given set of tuple-generating dependencies (TGDs), is it the case that the chase terminates for every input database? In view of the fact that this problem is undecidable, it is natural to ask whether known well-behaved

    更新日期:2020-08-18
  • Derandomization for Sliding Window Algorithms with Strict Correctness ∗
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-08-14
    Moses Ganardi, Danny Hucke, Markus Lohrey

    In the sliding window streaming model the goal is to compute an output value that only depends on the last n symbols from the data stream. Thereby, only space sublinear in the window size n should be used. Quite often randomization is used in order to achieve this goal. In the literature, one finds two different correctness criteria for randomized sliding window algorithms: (i) one can require that

    更新日期:2020-08-14
  • Preservation of Normality by Non-Oblivious Group Selection
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-08-14
    Olivier Carton, Joseph Vandehey

    We give two different proofs of the fact that non-oblivious selection via regular group sets preserves normality. Non-oblivious here means that whether or not a symbol is selected can depend on the symbol itself. One proof relies on the incompressibility of normal sequences, the other on the use of augmented dynamical systems.

    更新日期:2020-08-14
  • Exploration of Dynamic Cactuses with Sub-logarithmic Overhead
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-08-14
    David Ilcinkas, Ahmed M. Wade

    We study the problem of exploration by a mobile entity (agent) of a class of dynamic networks, namely constantly connected dynamic graphs. This problem has already been studied in the case where the agent knows the dynamics of the graph and the underlying graph is a ring of n vertices (Ilcinkas and Wade 2018). In this paper, we consider the same problem and we suppose that the underlying graph is a

    更新日期:2020-08-14
  • On Decidability of Theories of Regular Languages
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-08-13
    Sergey Dudakov, Boris Karlov

    This paper is dedicated to studying decidability properties of theories of regular languages with classical operations: union, concatenation, and the Kleene star. The theory with union only is a theory of some Boolean algebra, so it is decidable. We prove that the theory of regular languages with the Kleene star only is decidable. If we use union and concatenation simultaneously, then the theory becomes

    更新日期:2020-08-14
  • Computing the k -Visibility Region of a Point in a Polygon
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-08-11
    Yeganeh Bahoo, Prosenjit Bose, Stephane Durocher, Thomas C. Shermer

    Two points p and q in a simple polygon P are k-visible when the line segment pq crosses the boundary of P at most k times. Given a query point q, a positive integer k, and a polygon P, we design an algorithm that computes the region of P that is k-visible from q in O(nk) time, where n denotes the number of vertices of P. This region is called the k-visibility region of q. This is the first algorithm

    更新日期:2020-08-11
  • Satisfiability Algorithm for Syntactic Read- k -times Branching Programs
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-07-27
    Atsuki Nagao, Kazuhisa Seto, Junichi Teruyama

    The satisfiability of a given branching program is to determine whether there exists a consistent path from the root to 1-sink. In a syntactic read-k-times branching program, each variable appears at most k times in any path from the root to a sink. In a preliminary version of this paper, we provide a satisfiability algorithm for syntactic read-k-times branching programs with n variables and m edges

    更新日期:2020-07-27
  • Space Lower Bounds for the Signal Detection Problem
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-07-20
    Faith Ellen, Rati Gelashvili, Philipp Woelfel, Leqi Zhu

    Many shared memory algorithms have to deal with the problem of determining whether the value of a shared object has changed in between two successive accesses of that object by a process when the responses from both are the same. Motivated by this problem, we define the signal detection problem, which can be studied on a purely combinatorial level. Consider a system with n + 1 processes consisting

    更新日期:2020-07-20
  • Complexity and Algorithms for Semipaired Domination in Graphs
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-06-06
    Michael A. Henning, Arti Pandey, Vikash Tripathi

    For a graph G = (V, E) with no isolated vertices, a set \(D\subseteq V\) is called a semipaired dominating set of G if (i)D is a dominating set of G, and (ii)D can be partitioned into two element subsets such that the vertices in each two element set are at distance at most two. The minimum cardinality of a semipaired dominating set of G is called the semipaired domination number of G, and is denoted

    更新日期:2020-07-14
  • On the Average Case of MergeInsertion
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-06-30
    Florian Stober, Armin Weiß

    MergeInsertion, also known as the Ford-Johnson algorithm, is a sorting algorithm which, up to today, for many input sizes achieves the best known upper bound on the number of comparisons. Indeed, it gets extremely close to the information-theoretic lower bound. While the worst-case behavior is well understood, only little is known about the average case. This work takes a closer look at the average

    更新日期:2020-06-30
  • Consistent Query Answering for Primary Keys in Datalog
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-06-30
    Paraschos Koutris, Jef Wijsen

    We study the complexity of consistent query answering on databases that may violate primary key constraints. A repair of such a database is any consistent database that can be obtained by deleting a minimal set of tuples. For every Boolean query q, CERTAINTY(q) is the problem that takes a database as input and asks whether q evaluates to true on every repair. In Koutris and Wijsen (ACM Trans. Database

    更新日期:2020-06-30
  • Belga B-Trees
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-06-27
    Erik D. Demaine, John Iacono, Grigorios Koumoutsos, Stefan Langerman

    We revisitself-adjustingexternal memory tree data structures, which combine the optimal (and practical) worst-case I/O performances of B-trees, while adapting to the online distribution of queries. Our approach is analogous to undergoing efforts in the BST model, where Tango Trees (Demaine et al., SIAM J. Comput. 37(1), 240–251, 2007) were shown to be \(O(\log \log N)\)-competitive with the runtime

    更新日期:2020-06-27
  • Forward Looking Huffman Coding
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-06-25
    Shmuel T. Klein, Shoham Saadia, Dana Shapira

    Huffman coding is known to be optimal, yet its dynamic version may yield smaller compressed files. The best known bound is that the number of bits used by dynamic Huffman coding in order to encode a message of n characters is at most larger by n bits than the size of the file required by static Huffman coding. In particular, dynamic Huffman coding can also generate a larger encoded file than the static

    更新日期:2020-06-25
  • Dichotomy for Holant ∗ Problems on the Boolean Domain
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-06-22
    Jin-Yi Cai, Pinyan Lu, Mingji Xia

    Holant problems are a general framework to study counting problems. Both counting constraint satisfaction problems (#CSP) and graph homomorphisms are special cases. We prove a complexity dichotomy theorem for \(\text {Holant}^{*}(\mathcal {F})\), where \({\mathcal {F}}\) is a set of constraint functions on Boolean variables and taking complex values. The constraint functions need not be symmetric functions

    更新日期:2020-06-23
  • On Envy-Free Revenue Approximation for Combinatorial Buyers with Budgets
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-06-09
    Evangelos Markakis, Apostolos Ntokos, Orestis Telelis

    We study the computation of revenue-maximizing envy-free outcomes, in a monopoly market with budgeted buyers. Departing from previous works, we focus on buyers with combinatorial valuation functions, that are defined over subsets of distinct goods. Our results concern several classes of valuation functions. For single-minded budgeted buyers, we show a best possible polynomial-time approximation of

    更新日期:2020-06-09
  • Parameterized Complexity of Min-Power Asymmetric Connectivity
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-05-23
    Matthias Bentert, Roman Haag, Christian Hofer, Tomohiro Koana, André Nichterlein

    We investigate parameterized algorithms for the NP-hard problem Min-Power Asymmetric Connectivity (MinPAC) that has applications in wireless sensor networks. Given a directed arc-weighted graph, MinPAC asks for a strongly connected spanning subgraph minimizing the summed vertex costs. Here, the cost of each vertex is the weight of its heaviest outgoing arc in the chosen subgraph. We present linear-time

    更新日期:2020-05-23
  • Multiplication Algorithm Based on Collatz Function
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-05-15
    David Barina

    This article presents a new multiplication algorithm based on the Collatz function. Assuming the validity of the Collatz conjecture, the time complexity of multiplying two n-digit numbers is O(kn), where the k is the number of odd steps in the Collatz trajectory of the first multiplicand. Most likely, the algorithm is only of theoretical interest.

    更新日期:2020-05-15
  • Fast Algorithms for the Shortest Unique Palindromic Substring Problem on Run-Length Encoded Strings
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-05-09
    Kiichi Watanabe, Yuto Nakashima, Shunsuke Inenaga, Hideo Bannai, Masayuki Takeda

    For a string S, a palindromic substring S[i..j] is said to be a shortest unique palindromic substring (SUPS) for an interval [s,t] in S, if S[i..j] occurs exactly once in S, the interval [i,j] contains [s,t], and every palindromic substring containing [s,t] which is shorter than S[i..j] occurs at least twice in S. In this paper, we study the problem of answering SUPS queries on run-length encoded strings

    更新日期:2020-05-09
  • Unpopularity Factor in the Marriage and Roommates Problems
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-04-28
    Suthee Ruangwises, Toshiya Itoh

    Given a set A of n people, with each person having a preference list that ranks a subset of A as his/her acceptable partners in order of preference, we consider the Roommates Problem (rp) and the Marriage Problem (mp) of matching people with their partners. In rp there is no further restriction, while in mp only people of opposite genders can be acceptable partners. For a pair of matchings X and Y

    更新日期:2020-04-28
  • An Improved FPT Algorithm for Independent Feedback Vertex Set
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-04-25
    Shaohua Li, Marcin Pilipczuk

    We study the Independent Feedback Vertex Set problem — a variant of the classic Feedback Vertex Set problem where, given a graph G and an integer k, the problem is to decide whether there exists a vertex set \(S\subseteq V(G)\) such that G ∖ S is a forest and S is an independent set of size at most k. We present an \(\mathcal {O}^{\ast }((1+\varphi ^{2})^{k})\)-time FPT algorithm for this problem,

    更新日期:2020-04-25
  • Santha-Vazirani sources, deterministic condensers and very strong extractors
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-04-23
    Dmitry Gavinsky; Pavel Pudlák

    The notion of semi-random sources, also known as Santha-Vazirani (SV) sources, stands for a sequence of n bits, where the dependence of the i’th bit on the previousi − 1 bits is limited for every i ∈ [n]. If the dependence of the i’th bit on the remainingn − 1 bits is limited, then this is a strongSV-source. Even the strong SV -sources are known not to admit (universal) deterministic extractors, but

    更新日期:2020-04-23
  • Transition Property for Cube-Free Words
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-04-21
    Elena A. Petrova, Arseny M. Shur

    We study cube-free words over arbitrary non-unary finite alphabets and prove the following structural property: for every pair (u, v) of d-ary cube-free words, if u can be infinitely extended to the right and v can be infinitely extended to the left respecting the cube-freeness property, then there exists a “transition” word w over the same alphabet such that uwv is cube free. The crucial case is the

    更新日期:2020-04-21
  • Effective Categoricity of Automatic Equivalence and Nested Equivalence Structures
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-04-08
    Jacob Carson; Douglas Cenzer; Jeffrey B. Remmel

    We study automatic equivalence and nested equivalence structures. The goal is to compare and contrast these automatic structures with computable equivalence and nested equivalence structures. Equivalence structures \(\mathcal {A}\) may be characterized by their characters \(\chi ({\mathcal {A}})\) which encodes the number of equivalence classes of any given size. The characters of computably categorical

    更新日期:2020-04-08
  • Complexity of Fall Coloring for Restricted Graph Classes
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-04-08
    Juho Lauri, Christodoulos Mitillos

    We strengthen a result by Laskar and Lyle (Discrete Appl. Math. 157, 330–338 2009) by proving that it is NP-complete to decide whether a bipartite planar graph can be partitioned into three independent dominating sets. In contrast, we show that this is always possible for every maximal outerplanar graph with at least three vertices. Moreover, we extend their previous result by proving that deciding

    更新日期:2020-04-08
  • On the Fixed-Parameter Tractability of the Maximum Connectivity Improvement Problem
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-04-07
    Federico Corò; Gianlorenzo D’Angelo; Vahan Mkrtchyan

    In the Maximum Connectivity Improvement (MCI) problem, we are given a directed graph G = (V,E) and an integer B and we are asked to find B new edges to be added to G in order to maximize the number of connected pairs of vertices in the resulting graph. The MCI problem has been studied from the approximation point of view. In this paper, we approach it from the parameterized complexity perspective in

    更新日期:2020-04-07
  • First-Order Orbit Queries
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-04-04
    Shaull Almagor, Joël Ouaknine, James Worrell

    Orbit Problems are a class of fundamental reachability questions that arise in the analysis of discrete-time linear dynamical systems such as automata, Markov chains, recurrence sequences, and linear while loops. Instances of the problem comprise a dimension \(d\in \mathbb {N}\), a square matrix \(A\in \mathbb {Q}^{d\times d}\), and a query regarding the behaviour of some sets under repeated applications

    更新日期:2020-04-04
  • Conflict Free Version of Covering Problems on Graphs: Classical and Parameterized
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-02-28
    Pallavi Jain; Lawqueen Kanesh; Pranabendu Misra

    Let π be a family of graphs. In the classical π-Vertex Deletion problem, given a graph G and a positive integer k, the objective is to check whether there exists a subset S of at most k vertices such that G − S is in π. In this paper, we introduce the conflict free version of this classical problem, namely Conflict Free π-Vertex Deletion (CF-π-VD), and study this problem from the viewpoint of classical

    更新日期:2020-02-28
  • Correction to: Special Issue on Approximation and Online Algorithms
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-02-28
    Leah Epstein, Thomas Erlebach

    The original version of the article was inadvertently published with misinterpretations on author’s proof corrections on mathematical expressions.

    更新日期:2020-02-28
  • Longest Increasing Subsequence under Persistent Comparison Errors
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-02-20
    Barbara Geissmann

    We study the problem of computing a longest increasing subsequence in a sequence S of n distinct elements in the presence of persistent comparison errors. In this model, Braverman and Mossel (Noisy sorting without resampling, SODA 2008, pages 268–276, 2008) every comparison between two elements can return the wrong result with some fixed (small) probability p, and comparisons cannot be repeated. Computing

    更新日期:2020-02-20
  • Approximating Node-Weighted k -MST on Planar Graphs
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-02-03
    Jarosław Byrka; Mateusz Lewandowski; Joachim Spoerhase

    We study the problem of finding a minimum weight connected subgraph spanning at least k vertices on planar, node-weighted graphs. We give a (4 + ε)-approximation algorithm for this problem. We achieve this by utilizing the recent Lagrangian-multiplier preserving (LMP) primal-dual 3-approximation for the node-weighted prize-collecting Steiner tree problem by Byrka et al. (SWAT’16) and adopting an approach

    更新日期:2020-02-03
  • Correction to: Connecting Knowledge Compilation Classes and Width Parameters
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-01-25
    Antoine Amarilli, Florent Capelli, Mikaël Monet, Pierre Senellart

    The article title in the original publication contains an error. The correct title is presented in this Erratum. The online version of the original article can be found at: https://doi.org/10.1007/s00224-019-09930-2

    更新日期:2020-01-25
  • Dependences in Strategy Logic
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-01-08
    Patrick Gardy; Patricia Bouyer; Nicolas Markey

    Strategy Logic (SL) is a very expressive temporal logic for specifying and verifying properties of multi-agent systems: in SL, one can quantify over strategies, assign them to agents, and express LTL properties of the resulting plays. Such a powerful framework has two drawbacks: first, model checking SL has non-elementary complexity; second, the exact semantics of SL is rather intricate, and may not

    更新日期:2020-01-08
  • Deterministic Min-Cost Matching with Delays
    Theory Comput. Syst. (IF 0.497) Pub Date : 2020-01-06
    Yossi Azar; Amit Jacob Fanani

    We consider the online Minimum-Cost Perfect Matching with Delays (MPMD) problem introduced by Emek et al. (STOC 2016), in which a general metric space is given, and requests for points in space are submitted in different times in this space by an adversary. The goal is to match requests, while minimizing the sum of distances between matched pairs in addition to the time intervals passed from the moment

    更新日期:2020-01-06
  • Countable Sofic Shifts with a Periodic Direction
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-12-27
    Ilkka Törmä

    As a variant of the equal entropy cover problem, we ask whether all multidimensional sofic shifts with countably many configurations have SFT covers with countably many configurations. We answer this question in the negative by presenting explicit counterexamples. We formulate necessary conditions for a vertically periodic shift space to have a countable SFT cover, and prove that they are sufficient

    更新日期:2019-12-27
  • Generalized Graph k -Coloring Games
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-12-20
    Raffaello Carosi; Gianpiero Monaco

    We investigate pure Nash equilibria in generalized graphk-coloring games where we are given an edge-weighted undirected graph together with a set of k colors. Nodes represent players and edges capture their mutual interests. The strategy set of each player consists of k colors. The utility of a player v in a given state or coloring is given by the sum of the weights of edges {v, u} incident to v such

    更新日期:2019-12-20
  • Periodicity in Data Streams with Wildcards
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-12-20
    Funda Ergün; Elena Grigorescu; Erfan Sadeqi Azer; Samson Zhou

    We investigate the problem of detecting periodic trends within a string S of length n, arriving in the streaming model, containing at most k wildcard characters, where k = o(n). A wildcard character is a special character that can be assigned any other character. We say that S has wildcard-period p if there exists an assignment to each of the wildcard characters so that in the resulting stream the

    更新日期:2019-12-20
  • Optimizing Social Welfare for Network Bargaining Games in the Face of Instability, Greed and Idealism
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-12-04
    T.-H. Hubert Chan; Fei Chen; Li Ning

    Stable and balanced outcomes of network bargaining games have been investigated recently, but the existence of such outcomes requires that the linear program relaxation of a certain maximum matching problem have integral optimal solution. We propose an alternative model for network bargaining games in which each edge acts as a player, who proposes how to split the weight of the edge among the two incident

    更新日期:2019-12-04
  • On Normality in Shifts of Finite Type
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-12-04
    Nicolás Álvarez; Olivier Carton

    In this paper we consider the notion of normality of sequences in shifts of finite type. A sequence is normal if the frequency of each block exists and is equal to the Parry measure of the block. We give a characterization of normality in terms of incompressibility by lossless transducers. The result was already known in the case of the full shift.

    更新日期:2019-12-04
  • Distribution Policies for Datalog
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-12-04
    Bas Ketsman; Aws Albarghouthi; Paraschos Koutris

    Modern data management systems extensively use parallelism to speed up query processing over massive volumes of data. This trend has inspired a rich line of research on how to formally reason about the parallel complexity of join computation. In this paper, we go beyond joins and study the parallel evaluation of recursive queries. We introduce a novel framework to reason about multi-round evaluation

    更新日期:2019-12-04
  • On Limitations of Structured (Deterministic) DNNFs
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-12-04
    Beate Bollig; Matthias Buttkus

    The study of representations for propositional theories has been a central subject in knowledge compilation. Many known representations of propositional knowledge bases are restricted negation normal form circuits (NNFs) or binary decision diagrams. Sentential decision diagrams (SDDs) are one of them, by definition they are restricted structured deterministic DNNFs and more general than ordered binary

    更新日期:2019-12-04
  • Optimal Dislocation with Persistent Errors in Subquadratic Time
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-12-03
    Barbara Geissmann; Stefano Leucci; Chih-Hung Liu; Paolo Penna

    We study the problem of sorting N elements in the presence of persistent errors in comparisons: In this classical model, each comparison between two elements is wrong independently with some probability up to p, but repeating the same comparison gives always the same result. In this model, it is impossible to reliably compute a perfectly sorted permutation of the input elements. Rather, the quality

    更新日期:2019-12-03
  • Scheduling MapReduce Jobs on Identical and Unrelated Processors
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-11-29
    Dimitris Fotakis; Ioannis Milis; Orestis Papadigenopoulos; Vasilis Vassalos; Georgios Zois

    We consider non-preemptive scheduling of MapReduce jobs consisting of multiple map-reduce rounds so as to minimize their average weighted completion time on identical or unrelated processor environments. For identical processors, we present LP-based O(1)-approximation algorithms, while for unrelated processors the approximation ratio naturally depends on the maximum number of rounds of any job (which

    更新日期:2019-11-29
  • Computing Hitting Set Kernels By AC 0 -Circuits
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-11-28
    Max Bannach; Till Tantau

    Given a hypergraph H = (V,E), what is the smallest subset \(X \subseteq V\) such that e ∩ X≠∅ holds for all e ∈ E? This problem, known as the hitting set problem, is a basic problem in combinatorial optimization and has been studied extensively in both classical and parameterized complexity theory. There are well-known kernelization algorithms for it, which get a hypergraph H and a number k as input

    更新日期:2019-11-28
  • Advice Complexity of Priority Algorithms
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-11-13
    Allan Borodin; Joan Boyar; Kim S. Larsen; Denis Pankratov

    The priority model of “greedy-like” algorithms was introduced by Borodin, Nielsen, and Rackoff in 2002. We augment this model by allowing priority algorithms to have access to advice, i.e., side information precomputed by an all-powerful oracle. Obtaining lower bounds in the priority model without advice can be challenging and may involve intricate adversary arguments. Since the priority model with

    更新日期:2019-11-13
  • Extension Complexity of Formal Languages
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-11-06
    Hans Raj Tiwary

    In this article we undertake a study of extension complexity from the perspective of formal languages. We define a natural way to associate a family of polytopes with binary languages. This allows us to define the notion of extension complexity of formal languages. We prove several closure properties of languages admitting compact extended formulations. Furthermore, we give a sufficient machine characterization

    更新日期:2019-11-06
  • On the Stab Number of Rectangle Intersection Graphs
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-09-14
    Dibyayan Chakraborty; Mathew C. Francis

    We introduce the notion of stab number and exact stab number of rectangle intersection graphs, otherwise known as graphs of boxicity at most 2. A graph G is said to be a k-stabbable rectangle intersection graph, or k-SRIG for short, if it has a rectangle intersection representation in which k horizontal lines can be chosen such that each rectangle is intersected by at least one of them. If there exists

    更新日期:2019-09-14
  • On-line Search in Two-Dimensional Environment
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-09-11
    Dariusz Dereniowski; Dorota Osula

    We consider the following on-line pursuit-evasion problem. A team of mobile agents called searchers starts at an arbitrary node of an unknown network. Their goal is to execute a search strategy that guarantees capturing a fast and invisible intruder regardless of its movements using as few searchers as possible. We require that the strategy is connected and monotone, that is, at each point of the execution

    更新日期:2019-09-11
  • Efficient Dynamic Approximate Distance Oracles for Vertex-Labeled Planar Graphs
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-09-11
    Itay Laish; Shay Mozes

    Let G be a graph where each vertex is associated with a label. A vertex-labeled approximate distance oracle is a data structure that, given a vertex v and a label λ, returns a (1 + ε)-approximation of the distance from v to the closest vertex with label λ in G. Such an oracle is dynamic if it also supports label changes. In this paper we present three different dynamic approximate vertex-labeled distance

    更新日期:2019-09-11
  • Improving Selfish Routing for Risk-Averse Players
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-09-10
    Dimitris Fotakis; Dimitris Kalimeris; Thanasis Lianeas

    We investigate how and to which extent one can exploit risk-aversion and modify the perceived cost of the players in selfish routing so that the Price of Anarchy (PoA) wrt. the total latency is improved. The starting point is to introduce some small random perturbations to the edge latencies so that the expected latency does not change, but the perceived cost of the players increases, due to risk-aversion

    更新日期:2019-09-10
  • An Optimally-Competitive Algorithm for Maximum Online Perfect Bipartite Matching with i.i.d. Arrivals
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-09-07
    Minjun Chang; Dorit S. Hochbaum; Quico Spaen; Mark Velednitsky

    We present an optimally-competitive algorithm for the problem of maximum online perfect bipartite matching with i.i.d. arrivals. In this problem, we are given a known set of workers, a distribution over job types, and non-negative utility weights for each pair of worker and job types. At each time step, a job is drawn i.i.d. from the distribution over job types. Upon arrival, the job must be irrevocably

    更新日期:2019-09-07
  • Slopes of Multidimensional Subshifts
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-08-27
    Emmanuel Jeandel; Etienne Moutot; Pascal Vanier

    In this paper we study the directions of periodicity of multidimensional subshifts of finite type (SFTs) and of multidimensional effectively closed and sofic subshifts. A configuration of a subshift has a slope of periodicity if it is periodic in exactly one direction, the slope representing that direction. In this paper, we prove that \({{\Sigma }^{0}_{1}}\) sets of non-commensurable \(\mathbb {Z}^{2}\)

    更新日期:2019-08-27
  • On the Tree Conjecture for the Network Creation Game
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-08-16
    Davide Bilò; Pascal Lenzner

    Selfish Network Creation focuses on modeling real world networks from a game-theoretic point of view. One of the classic models by Fabrikant et al. (2003) is the network creation game, where agents correspond to nodes in a network which buy incident edges for the price of α per edge to minimize their total distance to all other nodes. The model is well-studied but still has intriguing open problems

    更新日期:2019-08-16
  • Enumeration Complexity of Conjunctive Queries with Functional Dependencies
    Theory Comput. Syst. (IF 0.497) Pub Date : 2019-08-16
    Nofar Carmeli; Markus Kröll

    We study the complexity of enumerating the answers of Conjunctive Queries (CQs) in the presence of Functional Dependencies (FDs). Our focus is on the ability to list output tuples with a constant delay in between, following a linear-time preprocessing. A known dichotomy classifies the acyclic self-join-free CQs into those that admit such enumeration, and those that do not. However, this classification

    更新日期:2019-08-16
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