Subjects -> COMPUTER SCIENCE (Total: 2313 journals)
    - ANIMATION AND SIMULATION (33 journals)
    - ARTIFICIAL INTELLIGENCE (133 journals)
    - AUTOMATION AND ROBOTICS (116 journals)
    - CLOUD COMPUTING AND NETWORKS (75 journals)
    - COMPUTER ARCHITECTURE (11 journals)
    - COMPUTER ENGINEERING (12 journals)
    - COMPUTER GAMES (23 journals)
    - COMPUTER PROGRAMMING (25 journals)
    - COMPUTER SCIENCE (1305 journals)
    - COMPUTER SECURITY (59 journals)
    - DATA BASE MANAGEMENT (21 journals)
    - DATA MINING (50 journals)
    - E-BUSINESS (21 journals)
    - E-LEARNING (30 journals)
    - ELECTRONIC DATA PROCESSING (23 journals)
    - IMAGE AND VIDEO PROCESSING (42 journals)
    - INFORMATION SYSTEMS (109 journals)
    - INTERNET (111 journals)
    - SOCIAL WEB (61 journals)
    - SOFTWARE (43 journals)
    - THEORY OF COMPUTING (10 journals)

COMPUTER SCIENCE (1305 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 872 Journals sorted alphabetically
3D Printing and Additive Manufacturing     Full-text available via subscription   (Followers: 27)
Abakós     Open Access   (Followers: 3)
ACM Computing Surveys     Hybrid Journal   (Followers: 29)
ACM Inroads     Full-text available via subscription   (Followers: 1)
ACM Journal of Computer Documentation     Free   (Followers: 4)
ACM Journal on Computing and Cultural Heritage     Hybrid Journal   (Followers: 5)
ACM Journal on Emerging Technologies in Computing Systems     Hybrid Journal   (Followers: 11)
ACM SIGACCESS Accessibility and Computing     Free   (Followers: 2)
ACM SIGAPP Applied Computing Review     Full-text available via subscription  
ACM SIGBioinformatics Record     Full-text available via subscription  
ACM SIGEVOlution     Full-text available via subscription  
ACM SIGHIT Record     Full-text available via subscription  
ACM SIGHPC Connect     Full-text available via subscription  
ACM SIGITE Newsletter     Open Access   (Followers: 1)
ACM SIGMIS Database: the DATABASE for Advances in Information Systems     Hybrid Journal  
ACM SIGUCCS plugged in     Full-text available via subscription  
ACM SIGWEB Newsletter     Full-text available via subscription   (Followers: 2)
ACM Transactions on Accessible Computing (TACCESS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 13)
ACM Transactions on Applied Perception (TAP)     Hybrid Journal   (Followers: 3)
ACM Transactions on Architecture and Code Optimization (TACO)     Hybrid Journal   (Followers: 9)
ACM Transactions on Asian and Low-Resource Language Information Processing (TALLIP)     Hybrid Journal  
ACM Transactions on Autonomous and Adaptive Systems (TAAS)     Hybrid Journal   (Followers: 10)
ACM Transactions on Computation Theory (TOCT)     Hybrid Journal   (Followers: 11)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 5)
ACM Transactions on Computer Systems (TOCS)     Hybrid Journal   (Followers: 19)
ACM Transactions on Computer-Human Interaction     Hybrid Journal   (Followers: 15)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 9)
ACM Transactions on Computing for Healthcare     Hybrid Journal  
ACM Transactions on Cyber-Physical Systems (TCPS)     Hybrid Journal   (Followers: 1)
ACM Transactions on Design Automation of Electronic Systems (TODAES)     Hybrid Journal   (Followers: 5)
ACM Transactions on Economics and Computation     Hybrid Journal  
ACM Transactions on Embedded Computing Systems (TECS)     Hybrid Journal   (Followers: 4)
ACM Transactions on Information Systems (TOIS)     Hybrid Journal   (Followers: 18)
ACM Transactions on Intelligent Systems and Technology (TIST)     Hybrid Journal   (Followers: 11)
ACM Transactions on Interactive Intelligent Systems (TiiS)     Hybrid Journal   (Followers: 6)
ACM Transactions on Internet of Things     Hybrid Journal   (Followers: 2)
ACM Transactions on Modeling and Performance Evaluation of Computing Systems (ToMPECS)     Hybrid Journal  
ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP)     Hybrid Journal   (Followers: 10)
ACM Transactions on Parallel Computing     Full-text available via subscription  
ACM Transactions on Reconfigurable Technology and Systems (TRETS)     Hybrid Journal   (Followers: 6)
ACM Transactions on Sensor Networks (TOSN)     Hybrid Journal   (Followers: 9)
ACM Transactions on Social Computing     Hybrid Journal  
ACM Transactions on Spatial Algorithms and Systems (TSAS)     Hybrid Journal   (Followers: 1)
ACM Transactions on Speech and Language Processing (TSLP)     Hybrid Journal   (Followers: 11)
ACM Transactions on Storage     Hybrid Journal  
ACS Applied Materials & Interfaces     Hybrid Journal   (Followers: 39)
Acta Informatica Malaysia     Open Access  
Acta Universitatis Cibiniensis. Technical Series     Open Access   (Followers: 1)
Ad Hoc Networks     Hybrid Journal   (Followers: 12)
Adaptive Behavior     Hybrid Journal   (Followers: 8)
Additive Manufacturing Letters     Open Access   (Followers: 3)
Advanced Engineering Materials     Hybrid Journal   (Followers: 32)
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
Advances in Adaptive Data Analysis     Hybrid Journal   (Followers: 9)
Advances in Artificial Intelligence     Open Access   (Followers: 31)
Advances in Catalysis     Full-text available via subscription   (Followers: 7)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 20)
Advances in Computer Engineering     Open Access   (Followers: 13)
Advances in Computer Science : an International Journal     Open Access   (Followers: 18)
Advances in Computing     Open Access   (Followers: 3)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 52)
Advances in Engineering Software     Hybrid Journal   (Followers: 26)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 19)
Advances in Human-Computer Interaction     Open Access   (Followers: 19)
Advances in Image and Video Processing     Open Access   (Followers: 20)
Advances in Materials Science     Open Access   (Followers: 19)
Advances in Multimedia     Open Access   (Followers: 1)
Advances in Operations Research     Open Access   (Followers: 13)
Advances in Remote Sensing     Open Access   (Followers: 59)
Advances in Science and Research (ASR)     Open Access   (Followers: 8)
Advances in Technology Innovation     Open Access   (Followers: 5)
AEU - International Journal of Electronics and Communications     Hybrid Journal   (Followers: 8)
African Journal of Information and Communication     Open Access   (Followers: 6)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 5)
AI EDAM     Hybrid Journal   (Followers: 2)
Air, Soil & Water Research     Open Access   (Followers: 6)
AIS Transactions on Human-Computer Interaction     Open Access   (Followers: 5)
Al-Qadisiyah Journal for Computer Science and Mathematics     Open Access   (Followers: 2)
AL-Rafidain Journal of Computer Sciences and Mathematics     Open Access   (Followers: 3)
Algebras and Representation Theory     Hybrid Journal  
Algorithms     Open Access   (Followers: 13)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 8)
American Journal of Computational Mathematics     Open Access   (Followers: 6)
American Journal of Information Systems     Open Access   (Followers: 4)
American Journal of Sensor Technology     Open Access   (Followers: 2)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 15)
Animation Practice, Process & Production     Hybrid Journal   (Followers: 4)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 14)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 16)
Annals of Pure and Applied Logic     Open Access   (Followers: 4)
Annals of Software Engineering     Hybrid Journal   (Followers: 12)
Annual Reviews in Control     Hybrid Journal   (Followers: 7)
Anuario Americanista Europeo     Open Access  
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 3)
Applied and Computational Harmonic Analysis     Full-text available via subscription  
Applied Artificial Intelligence: An International Journal     Hybrid Journal   (Followers: 17)
Applied Categorical Structures     Hybrid Journal   (Followers: 4)
Applied Clinical Informatics     Hybrid Journal   (Followers: 4)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 16)
Applied Computer Systems     Open Access   (Followers: 6)
Applied Computing and Geosciences     Open Access   (Followers: 3)
Applied Mathematics and Computation     Hybrid Journal   (Followers: 31)
Applied Medical Informatics     Open Access   (Followers: 11)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 4)
Applied Soft Computing     Hybrid Journal   (Followers: 13)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
Applied System Innovation     Open Access   (Followers: 1)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 4)
Archive of Numerical Software     Open Access  
Archives and Museum Informatics     Hybrid Journal   (Followers: 97)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
arq: Architectural Research Quarterly     Hybrid Journal   (Followers: 7)
Array     Open Access   (Followers: 1)
Artifact : Journal of Design Practice     Open Access   (Followers: 8)
Artificial Life     Hybrid Journal   (Followers: 7)
Asian Journal of Computer Science and Information Technology     Open Access   (Followers: 3)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Research in Computer Science     Open Access   (Followers: 4)
Assembly Automation     Hybrid Journal   (Followers: 2)
Automatic Control and Computer Sciences     Hybrid Journal   (Followers: 6)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Automatica     Hybrid Journal   (Followers: 13)
Automatika : Journal for Control, Measurement, Electronics, Computing and Communications     Open Access  
Automation in Construction     Hybrid Journal   (Followers: 8)
Balkan Journal of Electrical and Computer Engineering     Open Access  
Basin Research     Hybrid Journal   (Followers: 7)
Behaviour & Information Technology     Hybrid Journal   (Followers: 32)
BenchCouncil Transactions on Benchmarks, Standards, and Evaluations     Open Access   (Followers: 3)
Big Data and Cognitive Computing     Open Access   (Followers: 5)
Big Data Mining and Analytics     Open Access   (Followers: 10)
Biodiversity Information Science and Standards     Open Access   (Followers: 1)
Bioinformatics     Hybrid Journal   (Followers: 216)
Bioinformatics Advances : Journal of the International Society for Computational Biology     Open Access   (Followers: 1)
Biomedical Engineering     Hybrid Journal   (Followers: 11)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 11)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 43)
British Journal of Educational Technology     Hybrid Journal   (Followers: 93)
Bulletin of Taras Shevchenko National University of Kyiv. Series: Physics and Mathematics     Open Access  
c't Magazin fuer Computertechnik     Full-text available via subscription   (Followers: 1)
Cadernos do IME : Série Informática     Open Access  
CALCOLO     Hybrid Journal  
CALICO Journal     Full-text available via subscription  
Calphad     Hybrid Journal  
Canadian Journal of Electrical and Computer Engineering     Full-text available via subscription   (Followers: 14)
Catalysis in Industry     Hybrid Journal  
CCF Transactions on High Performance Computing     Hybrid Journal  
CCF Transactions on Pervasive Computing and Interaction     Hybrid Journal  
CEAS Space Journal     Hybrid Journal   (Followers: 6)
Cell Communication and Signaling     Open Access   (Followers: 3)
Central European Journal of Computer Science     Hybrid Journal   (Followers: 4)
CERN IdeaSquare Journal of Experimental Innovation     Open Access  
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 1)
Chaos, Solitons & Fractals : X     Open Access   (Followers: 1)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 13)
ChemSusChem     Hybrid Journal   (Followers: 7)
China Communications     Full-text available via subscription   (Followers: 8)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chip     Full-text available via subscription   (Followers: 2)
Ciencia     Open Access  
CIN : Computers Informatics Nursing     Hybrid Journal   (Followers: 11)
Circuits and Systems     Open Access   (Followers: 16)
CLEI Electronic Journal     Open Access  
Clin-Alert     Hybrid Journal   (Followers: 1)
Clinical eHealth     Open Access  
Cluster Computing     Hybrid Journal   (Followers: 1)
Cognitive Computation     Hybrid Journal   (Followers: 2)
Cognitive Computation and Systems     Open Access  
COMBINATORICA     Hybrid Journal  
Combinatorics, Probability and Computing     Hybrid Journal   (Followers: 4)
Combustion Theory and Modelling     Hybrid Journal   (Followers: 18)
Communication Methods and Measures     Hybrid Journal   (Followers: 12)
Communication Theory     Hybrid Journal   (Followers: 29)
Communications in Algebra     Hybrid Journal   (Followers: 1)
Communications in Partial Differential Equations     Hybrid Journal   (Followers: 2)
Communications of the ACM     Full-text available via subscription   (Followers: 59)
Communications of the Association for Information Systems     Open Access   (Followers: 15)
Communications on Applied Mathematics and Computation     Hybrid Journal   (Followers: 1)
COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering     Hybrid Journal   (Followers: 4)
Complex & Intelligent Systems     Open Access   (Followers: 1)
Complex Adaptive Systems Modeling     Open Access  
Complex Analysis and Operator Theory     Hybrid Journal   (Followers: 2)
Complexity     Hybrid Journal   (Followers: 8)
Computación y Sistemas     Open Access  
Computation     Open Access   (Followers: 1)
Computational and Applied Mathematics     Hybrid Journal   (Followers: 3)
Computational and Mathematical Methods     Hybrid Journal  
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2)
Computational and Mathematical Organization Theory     Hybrid Journal   (Followers: 1)
Computational and Structural Biotechnology Journal     Open Access   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 11)
Computational Astrophysics and Cosmology     Open Access   (Followers: 6)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 13)
Computational Biology Journal     Open Access   (Followers: 6)
Computational Brain & Behavior     Hybrid Journal   (Followers: 1)
Computational Chemistry     Open Access   (Followers: 3)
Computational Communication Research     Open Access   (Followers: 1)
Computational Complexity     Hybrid Journal   (Followers: 5)
Computational Condensed Matter     Open Access   (Followers: 1)

        1 2 3 4 5 6 7 | Last

Similar Journals
Journal Cover
Computational Complexity
Journal Prestige (SJR): 0.381
Citation Impact (citeScore): 1
Number of Followers: 5  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1420-8954 - ISSN (Online) 1016-3328
Published by Springer-Verlag Homepage  [2469 journals]
  • Expander-Based Cryptography Meets Natural Proofs

    • Free pre-print version: Loading...

      Abstract: Abstract We introduce new forms of attack on expander-based cryptography, and in particular on Goldreich’s pseudorandom generator and one-way function. Our attacks exploit low circuit complexity of the underlying expander’s neighbor function and/or of the local predicate. Our two key conceptual contributions are: We put forward the possibility that the choice of expander matters in expander-based cryptography. In particular, using expanders whose neighbor function has low circuit complexity might compromise the security of Goldreich’s PRG and OWF in certain settings. We show that the security of Goldreich’s PRG and OWF over arbitrary expanders is closely related to two other long-standing problems: The existence of unbalanced lossless expanders with low-complexity neighbor function, and limitations on circuit lower bounds (i.e., natural proofs). In particular, our results further motivate the investigation of affine/local unbalanced lossless expanders and of average-case lower bounds against DNF-XOR circuits. We prove two types of technical results. First, in the regime of quasipolynomial stretch (in which the output length of the PRG and the running time of the distinguisher are quasipolynomial in the seed length) we unconditionally break Goldreich’s PRG, when instantiated with a specific expander whose existence we prove, and for a class of predicates that match the parameters of the currently-best “hard” candidates. Secondly, conditioned on the existence of expanders whose neighbor functions have extremely low circuit complexity, we present attacks on Goldreich’s PRG in the regime of polynomial stretch. As one corollary, conditioned on the existence of the foregoing expanders, we show that either the parameters of natural properties for several constant-depth circuit classes cannot be improved, even mildly; or Goldreich’s PRG is insecure in the regime of a large polynomial stretch for some expander graphs, regardless of the predicate used.
      PubDate: 2022-03-16
       
  • Amplification with One NP Oracle Query

    • Free pre-print version: Loading...

      Abstract: Abstract We provide a complete picture of the extent to which amplification of success probability is possible for randomized algorithms having access to one NP oracle query, in the settings of two-sided, onesided, and zero-sided error. We generalize this picture to amplifying one-query algorithms with q-query algorithms, and we show our inclusions are tight for relativizing techniques.
      PubDate: 2022-02-05
      DOI: 10.1007/s00037-021-00219-w
       
  • The complexity of approximating the complex-valued Potts model

    • Free pre-print version: Loading...

      Abstract: Abstract We study the complexity of approximating the partition function of the q-state Potts model and the closely related Tutte polynomial for complex values of the underlying parameters. Apart from the classical connections with quantum computing and phase transitions in statistical physics, recent work in approximate counting has shown that the behaviour in the complex plane, and more precisely the location of zeros, is strongly connected with the complexity of the approximation problem, even for positive real-valued parameters. Previous work in the complex plane by Goldberg and Guo focused on q = 2, which corresponds to the case of the Ising model; for q > 2, the behaviour in the complex plane is not as well understood and most work applies only to the real-valued Tutte plane. Our main result is a complete classification of the complexity of the approximation problems for all non-real values of the parameters, by establishing #P-hardness results that apply even when restricted to planar graphs. Our techniques apply to all q \(\geq\) 2 and further complement/refine previous results both for the Ising model and the Tutte plane, answering in particular a question raised by Bordewich, Freedman, Lovász and Welsh in the context of quantum computations.
      PubDate: 2022-02-03
      DOI: 10.1007/s00037-021-00218-x
       
  • Rank and border rank of Kronecker powers of tensors and Strassen's laser
           method

    • Free pre-print version: Loading...

      Abstract: Abstract We prove that the border rank of the Kronecker square of the little Coppersmith–Winograd tensor \(T_{cw,q}\) is the square of its border rank for \(q > 2\) and that the border rank of its Kronecker cube is the cube of its border rank for \(q > 4\) . This answers questions raised implicitly by Coppersmith & Winograd (1990, §11) and explicitly by Bläser (2013, Problem 9.8) and rules out the possibility of proving new upper bounds on the exponent of matrix multiplication using the square or cube of a little Coppersmith–Winograd tensor in this range. In the positive direction, we enlarge the list of explicit tensors potentially useful for Strassen's laser method, introducing a skew-symmetric version of the Coppersmith–Winograd tensor, \(T_{skewcw,q}\) . For \(q = 2\) , the Kronecker square of this tensor coincides with the \(3\times 3\) determinant polynomial, \(\det_{3} \in \mathbb{C}^{9} \otimes \mathbb{C}^{9} \otimes \mathbb{C}^{9}\) , regarded as a tensor. We show that this tensor could potentially be used to show that the exponent of matrix multiplication is two. We determine new upper bounds for the (Waring) rank and the (Waring) border rank of \(\det_3\) , exhibiting a strict submultiplicative behaviour for \(T_{skewcw,2}\) which is promising for the laser method. We establish general results regarding border ranks of Kronecker powers of tensors, and make a detailed study of Kronecker squares of tensors in \(\mathbb{C}^{3} \otimes \mathbb{C}^{3} \otimes \mathbb{C}^{3}\) .
      PubDate: 2021-12-18
      DOI: 10.1007/s00037-021-00217-y
       
  • Correction to: Near-Optimal Lower Bounds on Regular Resolution Refutations
           of Tseitin Formulas for All Constant-Degree Graphs

    • Free pre-print version: Loading...

      PubDate: 2021-11-17
      DOI: 10.1007/s00037-021-00216-z
       
  • Factorization of Polynomials Given by Arithmetic Branching Programs

    • Free pre-print version: Loading...

      Abstract: Abstract Given a multivariate polynomial computed by an arithmetic branching program (ABP) of size s, we show that all its factors can be computed by arithmetic branching programs of size poly(s). Kaltofen gave a similar result for polynomials computed by arithmetic circuits. The previously known best upper bound for ABP-factors was poly \( (s^{ {\rm \log} s}) \) .
      PubDate: 2021-10-15
      DOI: 10.1007/s00037-021-00215-0
       
  • Lower Bounds for Arithmetic Circuits via the Hankel Matrix

    • Free pre-print version: Loading...

      Abstract: Abstract We study the complexity of representing polynomials by arithmetic circuits in both the commutative and the non-commutative settings. Our approach goes through a precise understanding of the more restricted setting where multiplication is not associative, meaning that we distinguish (xy)z from x(yz). Our first and main conceptual result is a characterization result: We show that the size of the smallest circuit computing a given non-associative polynomial is exactly the rank of a matrix constructed from the polynomial and called the Hankel matrix. This result applies to the class of all circuits in both commutative and non-commutative settings, and can be seen as an extension of the seminal result of Nisan giving a similar characterization for non-commutative algebraic branching programs. The study of the Hankel matrix provides a unifying approach for proving lower bounds for polynomials in the (classical) associative setting. Our key technical contribution is to provide generic lower bound theorems based on analyzing and decomposing the Hankel matrix. We obtain significant improvements on lower bounds for circuits with many parse trees, in both (associative) commutative and non-commutative settings, as well as alternative proofs of recent results proving superpolynomial and exponential lower bounds for different classes of circuits as corollaries of our characterization and decomposition results.
      PubDate: 2021-10-08
      DOI: 10.1007/s00037-021-00214-1
       
  • Near-Optimal Lower Bounds on Regular Resolution Refutations of Tseitin
           Formulas for All Constant-Degree Graphs

    • Free pre-print version: Loading...

      Abstract: Abstract This paper is motivated by seeking the exact complexity of resolution refutation of Tseitin formulas. We prove that the size of any regular resolution refutation of a Tseitin formula \( {\rm T}(G, c)\) based on a connected graph \({G} =(V, E)\) is at least \(2^{\Omega({\rm tw}(G)/ \log V )}\) , where \({\rm tw}(G)\) denotes the treewidth of a graph G. For constant-degree graphs, there is a known upper bound \(2^{\mathcal{O}({\rm tw}(G))}{\rm poly}( V )\) (Alekhnovich & Razborov Comput. Compl. 2011; Galesi, Talebanfard & Torán ACM Trans. Comput. Theory 2020), so our lower bound is tight up to a logarithmic factor in the exponent. Our proof consists of two steps. First, we show that any regular resolution refutation of an unsatisfiable Tseitin formula \({\rm T}(G, c) \) of size S can be converted to a read-once branching program computing a satisfiable Tseitin formula \({\rm T}(G,c')\) of size \(S^{{\mathcal{O}}({\rm log} V )}\) and this bound is tight. Second, we give the exact characterization of the nondeterministic read-once branching program (1-NBP) complexity of satisfiable Tseitin formulas in terms of structural properties of underlying graphs. Namely, we introduce a new graph measure, the component width (compw) and show that the size of a minimal \({1\text{-}\mathrm{NBP}}\) computing a satisfiable Tseitin formula \({\rm T}(G,c')\) based on a graph \({G} = (V, E)\) equals \(2^{compw}(G)\) up to a polynomial factor. Then we show that \(\Omega({\rm tw}(G)) \le {\rm compw}(G) \le {\mathcal{O}}({\rm tw}(G){\rm log}( V ))\) and both of these bounds are tight. The lower bound improves the recent result by Glinskih & Itsykson (Theory Comput. Syst. 2021).
      PubDate: 2021-08-27
      DOI: 10.1007/s00037-021-00213-2
       
  • An Exponential Separation Between MA and AM Proofs of Proximity

    • Free pre-print version: Loading...

      Abstract: Abstract Interactive proofs of proximity allow a sublinear-time verifier to check that a given input is close to the language, using a small amount of communication with a powerful (but untrusted) prover. In this work, we consider two natural minimally interactive variants of such proofs systems, in which the prover only sends a single message, referred to as the proof. The first variant, known as MA-proofs of Proximity (MAP), is fully non-interactive, meaning that the proof is a function of the input only. The second variant, known as AM-proofs of Proximity (AMP), allows the proof to additionally depend on the verifier's (entire) random string. The complexity of both MAPs and AMPs is the total number of bits that the verifier observes—namely, the sum of the proof length and query complexity. Our main result is an exponential separation between the power of MAPs and AMPs. Specifically, we exhibit an explicit and natural property \(\Pi\) that admits an AMP with complexity \(O(\log n)\) , whereas any MAP for \(\Pi\) has complexity \(\tilde{\Omega}(n^{1/4})\) , where n denotes the length of the input in bits. Our MAP lower bound also yields an alternate proof, which is more general and arguably much simpler, for a recent result of Fischer et al. (ITCS, 2014). Also, Aaronson (Quantum Information & Computation 2012) has shown a \(\Omega(n^{1/6})\) QMA lower bound for the same property \(\Pi\) . Lastly, we also consider the notion of oblivious proofs of proximity, in which the verifier's queries are oblivious to the proof. In this setting, we show that AMPs can only be quadratically stronger than MAPs. As an application of this result, we show an exponential separation between the power of public and private coin for oblivious interactive proofs of proximity.
      PubDate: 2021-08-18
      DOI: 10.1007/s00037-021-00212-3
       
  • The hardest halfspace

    • Free pre-print version: Loading...

      Abstract: Abstract We study the approximation of halfspaces \(h:\{0,1\}^n\to\{0,1\}\) in the infinity norm by polynomials and rational functions of any given degree. Our main result is an explicit construction of the “hardest” halfspace, for which we prove polynomial and rational approximation lower bounds that match the trivial upper bounds achievable for all halfspaces. This completes a lengthy line of work started by Myhill and Kautz (1961). As an application, we construct a communication problem that achieves essentially the largest possible separation, of O(n) versus \(2^{-\Omega(n)}\) , between the sign-rank and discrepancy. Equivalently, our problem exhibits a gap of log n versus \(\Omega(n)\) between the communication complexity with unbounded versus weakly unbounded error, improving quadratically on previous constructions and completing a line of work started by Babai, Frankl, and Simon (FOCS 1986). Our results further generalize to the k-party number-on-the-forehead model, where we obtain an explicit separation of log n versus \(\Omega(n/4^{n})\) for communication with unbounded versus weakly unbounded error.
      PubDate: 2021-08-03
      DOI: 10.1007/s00037-021-00211-4
       
  • Nondeterministic and Randomized Boolean Hierarchies in Communication
           Complexity

    • Free pre-print version: Loading...

      Abstract: Abstract We investigate the power of randomness in two-party communication complexity. In particular, we study the model where the parties can make a constant number of queries to a function that has an efficient one-sided-error randomized protocol. The complexity classes defined by this model comprise the Randomized Boolean Hierarchy, which is analogous to the Boolean Hierarchy but defined with one-sidederror randomness instead of nondeterminism. Our techniques connect the Nondeterministic and Randomized Boolean Hierarchies, and we provide a complete picture of the relationships among complexity classes within and across these two hierarchies. In particular, we prove that the Randomized Boolean Hierarchy does not collapse, and we prove a query-to-communication lifting theorem for all levels of the Nondeterministic Boolean Hierarchy and use it to resolve an open problem stated in the paper by Halstenberg and Reischuk (CCC 1988) which initiated the study of this hierarchy.
      PubDate: 2021-07-02
      DOI: 10.1007/s00037-021-00210-5
       
  • Correction to: Smooth and Strong PCPs

    • Free pre-print version: Loading...

      Abstract:
      Authors would like to correct the error in their publication.
      PubDate: 2021-06-10
      DOI: 10.1007/s00037-021-00208-z
       
  • Blackbox identity testing for sum of special ROABPs and its border class

    • Free pre-print version: Loading...

      Abstract: Abstract We look at the problem of blackbox polynomial identity testing (PIT) for the model of read-once oblivious algebraic branching programs (ROABP), where the number of variables is logarithmic to the input size of ROABP. We restrict width of ROABP to a constant and study the more general sum-of-ROABPs model. This model is nontrivial due to the arbitrary individual-degree. We give the first poly( \(s\) )-time blackbox PIT for sum of constant-many, size- \(s\) , \(O(log s)\) -variate constant-width ROABPs. The previous best for this model was quasi-polynomial time (Gurjar et al, CCC'15; Computational Complexity'17) which is comparable to brute-force in the log-variate setting. We also show that we can work with unbounded-many such ROABPs if each ROABP computes a homogeneous polynomial (or more generally for degree-preserving sums). We also give poly-time PIT for the border. We introduce two new techniques, both of which also work for the border version of the stated models. (1) The leading-degree-part of an ROABP can be made syntactically homogeneous in the same width. (2) There is a direct reduction from PIT of sum-of-ROABPs to PIT of single ROABP (over any field). Our methods improve the time complexity for PIT of sum-of-ROABPs in the log-variate regime.
      PubDate: 2021-06-10
      DOI: 10.1007/s00037-021-00209-y
       
  • Reversible Pebble Games and the Relation Between Tree-Like and General
           Resolution Space

    • Free pre-print version: Loading...

      Abstract: Abstract We show a new connection between the clause space measure in tree-like resolution and the reversible pebble game on graphs. Using this connection, we provide several formula classes for which there is a logarithmic factor separation between the clause space complexity measure in tree-like and general resolution. We also provide upper bounds for tree-like resolution clause space in terms of general resolution clause and variable space. In particular, we show that for any formula F, its tree-like resolution clause space is upper bounded by space \((\pi)\) \((\log({\rm time}(\pi))\) , where \(\pi\) is any general resolution refutation of F. This holds considering as space \((\pi)\) the clause space of the refutation as well as considering its variable space. For the concrete case of Tseitin formulas, we are able to improve this bound to the optimal bound space \((\pi)\log n\) , where n is the number of vertices of the corresponding graph
      PubDate: 2021-05-01
      DOI: 10.1007/s00037-021-00206-1
       
  • Lower Bounds for Matrix Factorization

    • Free pre-print version: Loading...

      Abstract: Abstract We study the problem of constructing explicit families of matrices which cannot be expressed as a product of a few sparse matrices. In addition to being a natural mathematical question on its own, this problem appears in various incarnations in computer science; the most significant being in the context of lower bounds for algebraic circuits which compute linear transformations, matrix rigidity and data structure lower bounds. We first show, for every constant d, a deterministic construction in time \({\rm exp}(n^{1-\Omega(1/d)})\) of a family \(\{M_n\}\) of \(n \times n\) matrices which cannot be expressed as a product \(M_n = A_1 \cdots A_d\) where the total sparsity of \(A_1,\ldots,A_d\) is less than \(n^{1+1/(2d)}\) . In other words, any depth-d linear circuit computing the linear transformation \(M_n\cdot {\bf x}\) has size at least \(n^{1+\Omega(1/d)}\) . The prior best lower bounds for this problem were barely super-linear, and were obtained by a long line of research based on the study of super-concentrators. We improve these lower bounds at the cost of a blow up in the time required to construct these matrices. Previously, however, such constructions were not known even in time \(2^{O(n)}\) with the aid of an NP oracle. We then outline an approach for proving improved lower bounds through a certain derandomization problem, and use this approach to prove asymptotically optimal quadratic lower bounds for natural special cases, which generalize many of the common matrix decompositions.
      PubDate: 2021-04-02
      DOI: 10.1007/s00037-021-00205-2
       
  • Subquadratic-Time Algorithms for Normal Bases

    • Free pre-print version: Loading...

      Abstract: Abstract For any finite Galois field extension K/F, with Galois group G = Gal (K/F), there exists an element \(\alpha \in \) K whose orbit \(G\cdot\alpha\) forms an F-basis of K. Such an \(\alpha\) is called a normal element, and \(G\cdot\alpha\) is a normal basis. We introduce a probabilistic algorithm for testing whether a given \(\alpha \in\) K is normal, when G is either a finite abelian or a metacyclic group. The algorithm is based on the fact that deciding whether \(\alpha\) is normal can be reduced to deciding whether \(\sum_{g \in G} g(\alpha)g \in\) K[G] is invertible; it requires a slightly subquadratic number of operations. Once we know that \(\alpha\) is normal, we show how to perform conversions between the power basis of K/F and the normal basis with the same asymptotic cost.
      PubDate: 2021-03-02
      DOI: 10.1007/s00037-020-00204-9
       
  • Nullstellensatz Size-Degree Trade-offs from Reversible Pebbling

    • Free pre-print version: Loading...

      Abstract: Abstract We establish an exactly tight relation between reversible pebblings of graphs and Nullstellensatz refutations of pebbling formulas, showing that a graph G can be reversibly pebbled in time t and space s if and only if there is a Nullstellensatz refutation of the pebbling formula over G in size t + 1 and degree s (independently of the field in which the Nullstellensatz refutation is made). We use this correspondence to prove a number of strong size-degree trade-offs for Nullstellensatz, which to the best of our knowledge are the first such results for this proof system.
      PubDate: 2021-02-12
      DOI: 10.1007/s00037-020-00201-y
       
  • Explicit List-Decodable Codes with Optimal Rate for Computationally
           Bounded Channels

    • Free pre-print version: Loading...

      Abstract: Abstract A stochastic code is a pair of encoding and decoding procedures (Enc, Dec) where \({{\rm Enc} : \{0, 1\}^{k} \times \{0, 1\}^{d} \rightarrow \{0, 1\}^{n}}\) . The code is (p, L)-list decodable against a class \(\mathcal{C}\) of “channel functions” \(C : \{0,1\}^{n} \rightarrow \{0,1\}^{n}\) if for every message \(m \in \{0,1\}^{k}\) and every channel \(C \in \mathcal{C}\) that induces at most pn errors, applying Dec on the “received word” C(Enc(m,S)) produces a list of at most L messages that contain m with high probability over the choice of uniform \(S \leftarrow \{0, 1\}^{d}\) . Note that both the channel C and the decoding algorithm Dec do not receive the random variable S, when attempting to decode. The rate of a code is \(R = k/n\) , and a code is explicit if Enc, Dec run in time poly(n). Guruswami and Smith (Journal of the ACM, 2016) showed that for every constants \(0 < p < \frac{1}{2}, \epsilon > 0\) and \(c > 1\) there exist a constant L and a Monte Carlo explicit constructions of stochastic codes with rate \(R \geq 1-H(p) - \epsilon\) that are (p, L)-list decodable for size \(n^c\) channels. Here, Monte Carlo means that the encoding and decoding need to share a public uniformly chosen \({\rm poly}(n^c)\) bit string Y, and the constructed stochastic code is (p, L)-list decodable with high probability over the choice of Y. Guruswami and Smith pose an open problem to give fully explicit (that is not Monte Carlo) explicit codes with the same parameters, under hardness assumptions. In this paper, we resolve this open problem, using a minimal assumption: the existence of poly-time computable pseudorandom generators for small circuits, which follows from standard complexity assumptions by Impagliazzo and Wigderson (STOC 97). Guruswami and Smith also asked to give a fully explicit unconditional constructions with the same parameters against \(O(\log n)\) -space online channels. (These are channels that have space \(O(\log n)\) and are allowed to read the input codeword in one pass.) We also resolve this open problem. Finally, we consider a tighter notion of explicitness, in which the running time of encoding and list-decoding algorithms does not increase, when increasing the complexity of the channel. We give explicit constructions (with rate approaching \(1 - H(p)\) for every \(p \leq p_{0}\) for some \(p_{0} >0\) ) for channels that are circuits of size \(2^{n^{\Omega(1/d)}}\) and depth d. Here, the running time of encoding and decoding is a polynomial that does not depend on the dept...
      PubDate: 2021-01-20
      DOI: 10.1007/s00037-020-00203-w
       
  • Resolution with Counting: Dag-Like Lower Bounds and Different Moduli

    • Free pre-print version: Loading...

      Abstract: Abstract Resolution over linear equations is a natural extension of the popular resolution refutation system, augmented with the ability to carry out basic counting. Denoted \({\rm Res}({\rm lin}_R)\) , this refutation system operates with disjunctions of linear equations with Boolean variables over a ring R, to refute unsatisfiable sets of such disjunctions. Beginning in the work of Raz & Tzameret (2008), through the work of Itsykson & Sokolov (2020) which focused on tree-like lower bounds, this refutation system was shown to be fairly strong. Subsequent work (cf. Garlik & Kołodziejczyk 2018; Itsykson & Sokolov 2020; Krajícek 2017; Krajícek & Oliveira 2018) made it evident that establishing lower bounds against general \({\rm Res}({\rm lin}_R)\) refutations is a challenging and interesting task since the system captures a ``minimal'' extension of resolution with counting gates for which no super-polynomial lower bounds are known to date. We provide the first super-polynomial size lower bounds against general (dag-like) resolution over linear equations refutations in the large characteristic regime. In particular, we prove that the subset-sum principle \(1+\sum\nolimits_{i=1}^{n}2^i x_i = 0\) requires refutations of exponential size over \(\mathbb{Q}\) . We use a novel lower bound technique: We show that under certain conditions every refutation of a subset-sum instance \(f=0\) must pass through a fat clause consisting of the equation \(f=\alpha\) for every \(\alpha\) in the image of f under Boolean assignments, or can be efficiently reduced to a proof containing such a clause. We then modify this approach to prove exponential lower bounds against tree-like refutations of any subset-sum instance that depends on n variables, hence also separating tree-like from dag-like refutations over the rationals. We then turn to the finite fields regime, showing that the work of Itsykson & Sokolov (2020), where tree-like lower bounds over \(\mathbb{F}_2\) were obtained, can be carried over and extended to every finite field. We establish new lower bounds and separations as follows: (i) For every pair of distinct primes \(p,q\) , there exist CNF formulas with short tree-like refutations in \({\rm Res}({\rm lin}{\mathbb{F}_p})\) that require exponential-size tree-like \({\rm Res}({\rm lin}{\mathbb{F}_q})\) refutations; (ii) random k-CNF formulas require exponential-size tree-like \({\rm Res}({\rm lin}{\mathbb{F}_p})\) refutations, for every prime p and constant k; and (iii) exponential-size lower bounds for tree-like \({\rm Res}({\rm lin}{\mathbb{F}})\) refutations of the pigeonhole principle, for every field \(\mathbb{F}\) .
      PubDate: 2021-01-08
      DOI: 10.1007/s00037-020-00202-x
       
  • Smooth and Strong PCPs

    • Free pre-print version: Loading...

      Abstract: Abstract Probabilistically checkable proofs (PCPs) can be verified based only on a constant amount of random queries, such that any correct claim has a proof that is always accepted, and incorrect claims are rejected with high probability (regardless of the given alleged proof). We consider two possible features of PCPs: \(\circ \quad\) A PCP is strong if it rejects an alleged proof of a correct claimwith probability proportional to its distance from some correctproof of that claim. \(\circ \quad\) A PCP is smooth if each location in a proof is queried with equalprobability. We prove that all sets in \(\mathcal{NP}\) have PCPs that are both smooth andstrong, are of polynomial length and can be verified based on a constantnumber of queries. This is achieved by following the proof of thePCP theorem of Arora et al. (JACM 45(3):501–555, 1998), providing astronger analysis of the Hadamard and Reed–Muller based PCPs anda refined PCP composition theorem. In fact, we show that any set in \(\mathcal{NP}\) has a smooth strong canonical PCP of Proximity (PCPP), meaningthat there is an efficiently computable bijection of \(\mathcal{NP}\) witnesses to correct proofs. This improves on the recent construction of Dinur et al. (in: Blum (ed) 10th innovations in theoretical computer science conference, ITCS, San Diego, 2019) of PCPPs that are strong canonical but inherently non-smooth. Our result implies the hardness of approximating the satisfiability of “stable” 3CNF formulae with bounded variable occurrence, where stable means that the number of clauses violated by an assignment is proportional to its distance from a satisfying assignment (in the relative Hamming metric). This proves a hypothesis used in the work of Friggstad, Khodamoradi and Salavatipour (in: Chan (ed) Proceedings of the 30th annual ACM-SIAM symposium on discrete algorithms, SODA, San Diego, 2019), suggesting a connection between the hardness of these instances and other stable optimization problems.
      PubDate: 2021-01-06
      DOI: 10.1007/s00037-020-00199-3
       
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
 


Your IP address: 34.231.147.28
 
Home (Search)
API
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-