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Proceedings [1990] 31st Annual Symposium on Foundations of Computer Science

22-24 Oct. 1990

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Displaying Results 1 - 25 of 92
  • No better ways to generate hard NP instances than picking uniformly at random

    Publication Year: 1990, Page(s):812 - 821 vol.2
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (712 KB)

    Distributed NP (DNP) problems are ones supplied with probability distributions of instances. It is shown that every DNP problem complete for P-time computable distributions is also complete for all distributions that can be sampled. This result makes the concept of average-case NP completeness robust and the question of the average-case complexity of complete DNP problems a natural alternative to ... View full abstract»

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  • Proceedings. 31st Annual Symposium on Foundations of Computer Science (Cat. No.90CH2925-6)

    Publication Year: 1990
    Request permission for commercial reuse | PDF file iconPDF (92 KB)
    Freely Available from IEEE
  • General weak random sources

    Publication Year: 1990, Page(s):534 - 543 vol.2
    Cited by:  Papers (23)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (656 KB)

    The following model for a weak random source is considered. The source is asked only once for R bits, and the source outputs an R-bit string such that no string has probability more than 2 -δR of being output. for some fixed δ>0. A pseudorandom generator that runs in time nO(log n) and simulates RP using as a seed a string from such a... View full abstract»

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  • Network synchronization with polylogarithmic overhead

    Publication Year: 1990, Page(s):514 - 522 vol.2
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (660 KB)

    The synchronizer is a simulation methodology for simulating a synchronous network by an asynchronous one, thus enabling the execution of a synchronous algorithm on an asynchronous network. Previously known synchronizers require each processor in the network to participate in each pulse of the synchronization process. The resulting communication overhead depends linearly on the number n of... View full abstract»

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  • Faster tree pattern matching

    Publication Year: 1990, Page(s):145 - 150 vol.1
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    Recently, R. Kosaraju (Proc. 30th IEEE Symp. on Foundations of Computer Science, 1989, p.178-83) gave an O(nm0.75 polylog(m))-step algorithm for tree pattern matching. The authors improve this result by designing a simple O(nm polylog (m )) algorithm View full abstract»

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  • Sparse partitions

    Publication Year: 1990, Page(s):503 - 513 vol.2
    Cited by:  Papers (60)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (900 KB)

    A collection of clustering and decomposition techniques that make possible the construction of sparse and locality-preserving representations for arbitrary networks is presented. The representation method considered is based on breaking the network G(V,E) into connected regions, or clusters, thus obtaining a cover for the network, i.e. a collection of clusters that cover... View full abstract»

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  • Efficient distribution-free learning of probabilistic concepts

    Publication Year: 1990, Page(s):382 - 391 vol.1
    Cited by:  Papers (13)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (980 KB)

    A model of machine learning in which the concept to be learned may exhibit uncertain or probabilistic behavior is investigated. Such probabilistic concepts (or p-concepts) may arise in situations such as weather prediction, where the measured variables and their accuracy are insufficient to determine the outcome with certainty. It is required that learning algorithms be both efficient and general ... View full abstract»

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  • Randomized online graph coloring

    Publication Year: 1990, Page(s):464 - 469 vol.2
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB)

    It is shown that randomization helps in coloring graphs online, and a simple randomized online algorithm is presented. For 3-colorable graphs the expected number of colors the algorithm uses is O(( n log n)1/2). The algorithm runs in polynomial time and compares well with the best known polynomial-time offline algorithms. A lower bound is proved for the random... View full abstract»

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  • The complexity of finding medians

    Publication Year: 1990, Page(s):778 - 787 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (624 KB)

    PF(#P) is characterized in a manner similar to M.W. Krentel's (1988) characterization of Pf(NP). If MidP is the class of functions that give the medians in the outputs of metric Turing machines, then it is shown that every function in PF(#P) is polynomial time 1-Turing reducible to a function in MidP and MidP⊆PF(#P); that is, PF(#P)=PF(MidP[1]). Intuitively, finding medians is as hard computa... View full abstract»

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  • On the exact complexity of string matching

    Publication Year: 1990, Page(s):135 - 144 vol.1
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (784 KB)

    The maximal number of character comparisons made by a linear-time string matching algorithm, given a text string of length n and a pattern string of length m over a general alphabet, is investigated. The number is denoted by c(n,m) or approximated by (1+C)n, where C is a universal constant. The subscript `online' is added when... View full abstract»

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  • Communication-optimal maintenance of replicated information

    Publication Year: 1990, Page(s):492 - 502 vol.2
    Cited by:  Papers (9)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (800 KB)

    It is shown that keeping track of history allows significant improvements in the realistic model of communication complexity of dynamic network protocols. The communication complexity for solving an arbitrary graph problem is improved from Θ(E) to Θ( V), thus achieving the lower bound. Moreover, O(V) is also the amortized complexity of solving an arbitrary fu... View full abstract»

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  • Augmenting graphs to meet edge-connectivity requirements

    Publication Year: 1990, Page(s):708 - 718 vol.2
    Cited by:  Papers (18)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (716 KB)

    The problem of determining the minimum number γ of edges to be added to a graph G so that in the resulting graph the edge-connectivity between every pair {u,v} of nodes is at least a prescribed value r(u,v) is treated. A min-max formula for γ is derived, and a polynomial-time algorithm for computing γ is described. The directe... View full abstract»

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  • Private computations over the integers

    Publication Year: 1990, Page(s):335 - 344 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (656 KB)

    The possibility of private distributed computations of n-argument functions defined over the integers is considered. A function f is t-private if there exists a protocol for computing f so that no coalition of ⩽t participants can infer any additional information from the execution of the protocol. It is shown that certain results for private computa... View full abstract»

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  • Finite-memory automata

    Publication Year: 1990, Page(s):683 - 688 vol.2
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    A model of computation dealing with infinite alphabets is proposed. The model is based on replacing the equality test by unification. It appears to be a natural generalization of the classical Rabin-Scott finite-state automata and possesses many of their properties View full abstract»

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  • Some triply-logarithmic parallel algorithms

    Publication Year: 1990, Page(s):871 - 881 vol.2
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (912 KB)

    It is established that several natural problems have triply logarithmic, or even faster, optimal parallel algorithms. These problems include: merging two sorted lists, where the values are drawn from a large, but restricted, domain on a CREW PRAM; finding all prefix minima, where the values are drawn from a restricted domain; and top-bottom global routing around a rectangle, a well-investigated pr... View full abstract»

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  • Permuting

    Publication Year: 1990, Page(s):372 - 379 vol.1
    Cited by:  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (612 KB)

    The fundamental problem of permuting the elements of an array according to some given permutation is addressed. The goal is to perform the permutation quickly using only a polylogarithmic number of bits of extra storage. The main result is an O(n log n)-time, O(log2n)-space worst case method. A simpler method is presented for the case in whic... View full abstract»

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  • Competitive k-server algorithms

    Publication Year: 1990, Page(s):454 - 463 vol.2
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (800 KB)

    Deterministic competitive k-server algorithms are given for all k and all metric spaces. This settles the k-server conjecture of M.S. Manasse et al. (1988) up to the competitive ratio. The best previous result for general metric spaces was a three-server randomized competitive algorithm and a nonconstructive proof that a deterministic three-server competitive algorithm e... View full abstract»

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  • A characterization of #P by arithmetic straight line programs

    Publication Year: 1990, Page(s):26 - 34 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (580 KB)

    #P functions are characterized by certain straight-line programs of multivariate polynomials. The power of this characterization is illustrated by a number of consequences. These include a somewhat simplified proof of S. Toda's (1989) theorem that PH⊆P#P, as well as an infinite class of potentially inequivalent checkable functions View full abstract»

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  • Multiple non-interactive zero knowledge proofs based on a single random string

    Publication Year: 1990, Page(s):308 - 317 vol.1
    Cited by:  Papers (8)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (784 KB)

    The authors solve the two major open problems associated with noninteractive zero-knowledge proofs: how to enable polynomially many provers to prove in writing polynomially many theorems based on the basis of a single random string, and how to construct such proofs under general (rather than number-theoretic) assumptions. The constructions can be used in cryptographic applications in which the pro... View full abstract»

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  • Hidden surface removal for axis-parallel polyhedra

    Publication Year: 1990, Page(s):252 - 261 vol.1
    Cited by:  Patents (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (812 KB)

    An efficient, output-sensitive method for computing the visibility map of a set of axis-parallel polyhedra (i.e. polyhedra with their faces and edges parallel to the coordinate axes) as seen from a given viewpoint is introduced. For nonintersecting polyhedra with n edges in total, the algorithm runs in time O((n+k )log n), where k is the comple... View full abstract»

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  • Bounds on tradeoffs between randomness and communication complexity

    Publication Year: 1990, Page(s):766 - 775 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (592 KB)

    A quantitative investigation of the power of randomness in the context of communication complexity is initiated. The authors prove general lower bounds on the length of the random input of parties computing a function f, depending on the number of bits communicated and the deterministic communication complexity of f. Four standard models for communication complexity are considere... View full abstract»

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  • Towards a DNA sequencing theory (learning a string)

    Publication Year: 1990, Page(s):125 - 134 vol.1
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (644 KB)

    Mathematical frameworks suitable for massive automated DNA sequencing and for analyzing DNA sequencing algorithms are studied under plausible assumptions. The DNA sequencing problem is modeled as learning a superstring from its randomly drawn substrings. Under certain restrictions, this may be viewed as learning a superstring in L.G. Valiant's (1984) learning model, and in this case the author giv... View full abstract»

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  • A tree-partitioning technique with applications to expression evaluation and term matching

    Publication Year: 1990, Page(s):163 - 172 vol.1
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (656 KB)

    A tree-partitioning technique is proposed and applied to expression evaluation and term matching. It was shown recently that the problem of evaluating an arithmetic expression is in NC1, and an O(log N)-depth, O(N2 log N)-size circuit for this problem was described. The size is reduced to O(N logk N... View full abstract»

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  • On threshold circuits for parity

    Publication Year: 1990, Page(s):397 - 404 vol.1
    Cited by:  Papers (10)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (452 KB)

    Motivated by, the problem of understanding the limitations of neural networks for representing Boolean functions, the authors consider size-depth tradeoffs for threshold circuits that compute the parity function. They give an almost optimal lower bound on the number of edges of any depth-2 threshold circuit that computes the parity function with polynomially bounded weights. The main technique use... View full abstract»

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  • Online algorithms for finger searching

    Publication Year: 1990, Page(s):480 - 489 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (720 KB)

    The technique of speeding up access into search structures by maintaining fingers that point to various locations of the search structure is considered. The problem of choosing, in a large search structure, locations at which to maintain fingers is treated. In particular, a server problem in which k servers move along a line segment of length m, where m is the number of ... View full abstract»

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