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Computational Complexity, 2003. Proceedings. 18th IEEE Annual Conference on

Date 7-10 July 2003

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Displaying Results 1 - 25 of 34
  • Rectangle size bounds and threshold covers in communication complexity

    Publication Year: 2003, Page(s):118 - 134
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (449 KB) | HTML iconHTML

    We investigate the power of the most important lower bound technique in randomized communication complexity, which is based on an evaluation of the maximal size of approximately monochromatic rectangles, with respect to arbitrary distributions on the inputs. While it is known that the 0-error version of this bound is polynomially tight for deterministic communication, nothing in this direction is ... View full abstract»

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  • Near-optimal lower bounds on the multi-party communication complexity of set disjointness

    Publication Year: 2003, Page(s):107 - 117
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (564 KB) | HTML iconHTML

    We study the communication complexity of the set disjointness problem in the general multiparty model. For t players, each holding a subset of a universe of size n, we establish a near-optimal lower bound of Ω(n/(t log t)) on the communication complexity of the problem of determining whether their sets are disjoint. In the more restrictive one-way communication model, in which the players ar... View full abstract»

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  • Optimal separation of EROW and CROW PRAMs

    Publication Year: 2003, Page(s):93 - 104
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (370 KB) | HTML iconHTML

    We consider the problem of evaluating a Boolean function on PRAMs. We exhibit a Boolean function f:{0,1}n→{0,1} that can be evaluated in time O(log log n) in a deterministic CROW (concurrent read owner write) PRAM model, but requires time Ω(log n) in EROW (exclusive read owner write) PRAM. Our lower bound also holds in the randomized Monte Carlo EROW model. This Boolean funct... View full abstract»

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  • Quantum query complexity and semi-definite programming

    Publication Year: 2003, Page(s):179 - 193
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (426 KB) | HTML iconHTML

    We reformulate quantum query complexity in terms of inequalities and equations for a set of positive semidefinite matrices. Using the new formulation we: 1) show that the workspace of a quantum computer can be limited to at most n+k qubits (where n and k are the number of input and output bits respectively) without reducing the computational power of the model; 2) give an algorithm that on input t... View full abstract»

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  • Bounded nondeterminism and alternation in parameterized complexity theory

    Publication Year: 2003, Page(s):13 - 29
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (712 KB) | HTML iconHTML

    We give machine characterisations and logical descriptions of a number of parameterized complexity classes. The focus of our attention is the class W[P], which we characterise as the class of all parameterized problems decidable by a nondeterministic fixed-parameter tractable algorithm, whose use of nondeterminism is bounded in terms of the parameter. We give similar characterisations for AW[P], t... View full abstract»

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  • Quantum certificate complexity

    Publication Year: 2003, Page(s):171 - 178
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (524 KB) | HTML iconHTML

    Given a Boolean function f, we study two natural generalizations of the certificate complexity C(f): the randomized certificate complexity RC(f) and the quantum certificate complexity QC(f). Using Ambainis' adversary method, we exactly characterize QC(f) as the square root of RC(f). We then use this result to prove the new relation R0(f)=O(Q2(f)2Q0(f)log... View full abstract»

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  • Memoization and DPLL: formula caching proof systems

    Publication Year: 2003, Page(s):248 - 259
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (585 KB) | HTML iconHTML

    A fruitful connection between algorithm design and proof complexity is the formalization of the DPLL approach to satisfiability testing in terms of tree-like resolution proofs. We consider extensions of the DPLL approach that add some version of memoization, remembering formulas the algorithm has previously shown unsatisfiable. Various versions of such formula caching algorithms have been suggeste... View full abstract»

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  • On statistical query sampling and NMR quantum computing

    Publication Year: 2003, Page(s):194 - 205
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (614 KB) | HTML iconHTML

    We introduce a "statistical query sampling" model, in which the goal of an algorithm is to produce an element in a hidden set S⊆{0,1}n with reasonable probability. The algorithm gains information about S through oracle calls (statistical queries), where the algorithm submits a query function g(·) and receives an approximation to Prx∈S[g(x)=1]. We show how thi... View full abstract»

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  • Uniform hardness vs. randomness tradeoffs for Arthur-Merlin games

    Publication Year: 2003, Page(s):33 - 47
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1360 KB) | HTML iconHTML

    Impagliazzo and Wigderson proved a uniform hardness vs. randomness "gap result" for BPP. We show an analogous result for AM: Either Arthur-Merlin protocols are very strong and everything in E=DTIME(2O(n)) can be proved to a subexponential time verifier, or else Arthur-Merlin protocols are weak and every language in AM has a polynomial time nondeterministic algorithm in the uniform avera... View full abstract»

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  • Proceedings 18th IEEE Annual Conference on Computational Complexity

    Publication Year: 2003
    Request permission for commercial reuse | PDF file iconPDF (217 KB)
    Freely Available from IEEE
  • Author index

    Publication Year: 2003, Page(s): 339
    Request permission for commercial reuse | PDF file iconPDF (33 KB)
    Freely Available from IEEE
  • The complexity of unique k-SAT: an isolation lemma for k-CNFs

    Publication Year: 2003, Page(s):135 - 141
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (453 KB) | HTML iconHTML

    We provide some evidence that unique k-SAT is as hard to solve as general k-SAT, where k-SAT denotes the satisfiability problem for k-CNFs and unique k-SAT is the promise version where the given formula has 0 or 1 solutions. Namely, defining for each k≥1, sk=inf{δ≥0|∃aO(2δn)-time randomized algorithm for k-SAT} and, similarly, σk=inf{&... View full abstract»

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  • Minimization of decision trees is hard to approximate

    Publication Year: 2003, Page(s):84 - 92
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (501 KB) | HTML iconHTML

    Decision trees are representations of discrete functions with widespread applications in, e.g., complexity theory and data mining and exploration. In these areas it is important to obtain decision trees of small size. The minimization problem for decision trees is known to be NP-hard. The problem is even hard to approximate up to any constant factor. View full abstract»

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  • Lower bounds for predecessor searching in the cell probe model

    Publication Year: 2003, Page(s):73 - 83
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (538 KB) | HTML iconHTML

    We consider a fundamental problem in data structures, static predecessor searching: Given a subset S of size n from the universe [m], store S so that queries of the form "What is the predecessor of x in S?" can be answered efficiently. We study this problem in the cell probe model introduced by Yao [1981]. Recently, Beame and Fich [2002] obtained optimal bounds on the number of probes needed by an... View full abstract»

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  • Extremal properties of polynomial threshold functions

    Publication Year: 2003, Page(s):3 - 12
    Cited by:  Papers (5)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (370 KB) | HTML iconHTML

    We give new extremal bounds on polynomial threshold function (PTF) representations of Boolean functions. Our results include the following: 1) Almost every Boolean function has PTF degree at most n/2+O(√(n log n)). Together with results of Anthony and Alon, we establish a conjecture of Wang and Williams [1991] and Aspnes, Beigel, Furst, and Rudich [1994] up to lower order terms. 2) Every Boo... View full abstract»

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  • Vertex cover might be hard to approximate to within 2-ϵ

    Publication Year: 2003, Page(s):379 - 386
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (529 KB) | HTML iconHTML

    Based on a conjecture regarding the power of unique 2-prover-1-round games presented in [S. Khot, (2002)], we show that vertex cover is hard to approximate within any constant factor better than 2. We actually show a stronger result, namely, based on the same conjecture, vertex cover on k-uniform hypergraphs is hard to approximate within any constant factor better than k. View full abstract»

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  • Hardness vs. randomness within alternating time

    Publication Year: 2003, Page(s):53 - 69
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (462 KB) | HTML iconHTML

    We study the complexity of building pseudorandom generators (PRGs) with logarithmic seed length from hard functions. We show that, starting from a function f:{0,1}l→{0,1} that is mildly hard on average, i.e. every circuit of size 2Ω(l) fails to compute f on at least a 1/poly(l) fraction of inputs, we can build a PRG: {0,1}O(logn)→{0,1}n c... View full abstract»

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  • Improved inapproximability of lattice and coding problems with preprocessing

    Publication Year: 2003, Page(s):363 - 370
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (519 KB) | HTML iconHTML

    We show that the closest vector problem with preprocessing (CVPP) is NP-hard to approximate to within √3-ε for any ε>0. In addition, we show that the nearest codeword problem with preprocessing (NCPP) is NP-hard to approximate to within 3-ε. These results improve the results of Feige and Micciancio (2002). We also present the first inapproximability result for the relatively n... View full abstract»

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  • Universal languages and the power of diagonalization

    Publication Year: 2003, Page(s):337 - 346
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (567 KB) | HTML iconHTML

    We define and study strong diagonalization and compare it to weak diagonalization, implicit in the work of D. Kozen (1980). Kozen's result shows that virtually every separation can be recast as weak diagonalization. We show that there are classes of languages, which cannot be separated by strong diagonalization and provide evidence that strong diagonalization does not relativize. We also define tw... View full abstract»

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  • List decoding with side information

    Publication Year: 2003, Page(s):300 - 309
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (593 KB) | HTML iconHTML

    Under list decoding of error-correcting codes, the decoding algorithm is allowed to output a small list of codewords that are close to the noisy received word. This relaxation permits recovery even under very high noise thresholds. We consider one possible scenario that would permit disambiguating between the elements of the list, namely where the sender of the message provides some hopefully smal... View full abstract»

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  • Parameterized complexity for the skeptic

    Publication Year: 2003, Page(s):147 - 168
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (726 KB) | HTML iconHTML

    The goal is to provide a tourist guide, with an eye towards structural issues, to what I consider some of the major highlights of parameterized complexity. View full abstract»

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  • A strong inapproximability gap for a generalization of minimum bisection

    Publication Year: 2003, Page(s):371 - 378
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (322 KB) | HTML iconHTML

    As a problem with similar properties to minimum bisection, we consider the following: given a homogeneous system of linear equations over Z2, with exactly k variables in each equation, find a balanced assignment that minimizes the number of satisfied equations. A balanced assignment is one which contains an equal number of 0s and 1s. When k=2, this is the minimum bisection problem. We c... View full abstract»

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  • Proving SAT does not have small circuits with an application to the two queries problem

    Publication Year: 2003, Page(s):347 - 350
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (260 KB) | HTML iconHTML

    We show that if SAT does not have small circuits, then there must exist a small number of formulas such that every small circuit fails to compute satisfiability correctly on at least one of these formulas. We use this result to show that if PNP[1]=PNP[2], then the polynomial-time hierarchy collapses to S2P⊆Σ2p∩Π... View full abstract»

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  • Disjoint NP-pairs

    Publication Year: 2003, Page(s):313 - 332
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (532 KB) | HTML iconHTML

    We study the question of whether the class DisNP of disjoint pairs (A, B) of NP-sets contains a complete pair. The question relates to the question of whether optimal proof systems exist, and we relate it to the previously studied question of whether there exists a disjoint pair of NP-sets that is NP-hard. We show under reasonable hypotheses that nonsymmetric disjoint NP-pairs exist, which provide... View full abstract»

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  • Inapproximability - some history and some open problems

    Publication Year: 2003, Page(s):265 - 266
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (225 KB) | HTML iconHTML

    The purpose of this talk is to give an overview of the status of some problems in approximability. View full abstract»

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