By Topic

[1991] Proceedings 32nd Annual Symposium of Foundations of Computer Science

1-4 Oct. 1991

Filter Results

Displaying Results 1 - 25 of 86
  • Proceedings 32nd Annual Symposium on Foundations of Computer Science (Cat. No.91CH3062-7)

    Publication Year: 1991
    Request permission for commercial reuse | PDF file iconPDF (17 KB)
    Freely Available from IEEE
  • Randomized multidimensional search trees: further results in dynamic sampling

    Publication Year: 1991, Page(s):216 - 227
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1116 KB)

    The use of randomization in dynamic search structures by means of a technique called dynamic sampling is investigated. In particular, an efficient algorithm for dynamic (logarithmic time) point location in 3-D partitions induced by a set of possibly interesting polygons in R 3 is given. The expected running time of the algorithm on a random sequence of updates is close to optim... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Variation ranks of communication matrices and lower bounds for depth two circuits having symmetric gates with unbounded fan-in

    Publication Year: 1991, Page(s):777 - 782
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    An exponential lower bound for depth two circuits with arbitrary symmetric gates in the bottom level and with a MODm-gate in the top level is proved. This solves a problem posed by R. Smolensky (1990). The method uses the variation rank of communication matrices. A variant of this method is used for deriving lower bounds for the size of depth-two circuits having a threshold gate at the ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Reporting points in halfspaces

    Publication Year: 1991, Page(s):207 - 215
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (736 KB)

    The author considers the halfspace range reporting problem: Given a finite set P of points in Ed, preprocess it so that given a query halfspace γ, the points of p∩γ can be reported efficiently. It is shown that, with almost linear storage, this problem can be solved substantially more efficiently than the more general simplex range searching pr... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On the computational power of sigmoid versus Boolean threshold circuits

    Publication Year: 1991, Page(s):767 - 776
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (664 KB)

    The power of constant depth circuits with sigmoid (i.e., smooth) threshold gates for computing Boolean functions is examined. It is shown that, for depth 2, constant size circuits of this type are strictly more powerful than constant size Boolean threshold circuits (i.e., circuits with Boolean threshold gates). On the other hand it turns out that, for any constant depth d, polynomial size... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dynamic maintenance of geometric structures made easy

    Publication Year: 1991, Page(s):197 - 206
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (896 KB)

    The problem of dynamically maintaining geometric structures is considered. A technique is proposed that uses randomized incremental algorithms which are augmented to allow deletions of objects. A model for distributions on the possible input sequences of insertions and deletions is developed and analyzed using R. Seidel's backwards analysis. It is further shown how to apply this to maintain Vorono... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Adaptive dictionary matching

    Publication Year: 1991, Page(s):760 - 766
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (524 KB)

    Semiadaptive and fully adaptive dictionary matching algorithms are presented. In the fully adaptive algorithm, the dictionary is processed in time O(|D| log |D|). Inserting a new pattern Pk+1 into the dictionary can be done in time O |PK+1| log |D|). A dictionary pattern can be deleted in time O(log |... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Shrinkage of de Morgan formulae under restriction

    Publication Year: 1991, Page(s):324 - 333
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (616 KB)

    It is shown that a random restriction leaving only a fraction ∈ of the input variables unassigned reduces the expected de Morgan formula size of the induced function by a factor of O(∈ 1.63). This is an improvement over previous results. The new exponent yields an increased lower bound of approximately n2.63 for the de Morgan formula size of a func... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Efficient exponentiation in finite field

    Publication Year: 1991, Page(s):384 - 391
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (512 KB)

    Optimal sequential and parallel algorithms for exponentiation in a finite field extension are presented, assuming that a normal basis over the ground field is given View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Asymptotically optimal PRAM emulation on faulty hypercubes

    Publication Year: 1991, Page(s):440 - 446
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (588 KB)

    A scheme for emulating the parallel random access machine (PRAM) on a faulty hypercube is presented. All components of the hypercube, including the memory modules, are assumed to be subject to failure. The faults may occur at any time during the emulation and the system readjusts dynamically. The scheme, which rests on L.G. Valiant's BSP model (1990), is the first to achieve optimal and work-prese... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Using approximation algorithms to design parallel algorithms that may ignore processor allocation

    Publication Year: 1991, Page(s):711 - 722
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1060 KB)

    A framework is presented for designing parallel algorithms that may ignore processor allocation. A number of fast approximation algorithms are developed, and it is shown how to use these algorithms to simulate any algorithm that fits this framework in a work-preserving fashion on a randomized CRCW PRAM. Several applications of the approach to parallel computational geometry are given View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Languages that are easier than their proofs

    Publication Year: 1991, Page(s):19 - 28
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (800 KB)

    Languages in NP are presented for which it is harder to prove membership interactively than it is to decide this membership. Similarly, languages where checking is harder than computing membership are presented. Under assumptions about triple-exponential time, incoherent sets in NP are constructed. Without any assumptions, incoherent sets are constructed in DSPACE (n to the log ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Randomized multidimensional search trees: lazy balancing and dynamic shuffling

    Publication Year: 1991, Page(s):180 - 196
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1628 KB)

    A randomized technique, called dynamic shuffling, is given for multidimensional dynamic search. This technique, when specialized to the problem of searching in sorted lists, yields the previously known randomized binary trees (treaps). The crux of the technique is a multidimensional generalization of the rotation operation on binary search trees. Simultaneously, it is shown how to dynamize the ran... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Progress measures for complementation ω-automata with applications to temporal logic

    Publication Year: 1991, Page(s):358 - 367
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (656 KB)

    A new approach to complementing ω-automata, which are finite-state automata defining languages of infinite words, is given. Instead of using usual combinatorial or algebraic properties of transition relations, it is shown that a graph-theoretic approach based on the notion of progress measures is a potent tool for complementing ω-automata. Progress measures are applied to the classical... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • How to pack better than best fit: tight bounds for average-case online bin packing

    Publication Year: 1991, Page(s):752 - 759
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (644 KB)

    An O(n log n)-time online algorithm is given for packing items i.i.d. uniform on [0, 1] into bins of size 1 with expected wasted space Θ(n1/2 log 1/2 n). This matches the lowest bound that no online algorithm can achieve O(n1/2 log 1/2 n) wasted space. It is done by analyzing ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Lower bounds for data structure problems on RAMs

    Publication Year: 1991, Page(s):622 - 631
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (720 KB)

    A technique is described for deriving lower bounds and tradeoffs for data structure problems. Two quantities are defined. The output variability depends only on the model of computation. It characterizes in some sense the power of a model. The problem variability depends only on the problem under consideration. It characterizes in some sense the difficulty of the problem. The first theorem states ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Better bounds for threshold formulas

    Publication Year: 1991, Page(s):314 - 323
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (708 KB)

    The computation of threshold functions using formulas over the basis {AND, OR, NOT} is considered. It is shown that every monotone formula that computes the threshold function Tkn/2⩽kn2, has size Ω(nk log (n/(k-1))). The same lower bound is shown to hold even in the stronger monotone contact networks model. ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A parallel algorithmic version of the local lemma

    Publication Year: 1991, Page(s):586 - 593
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    The Lovasz local lemma (1975) is a tool that enables one to show that certain events hold with positive, though very small probability. It often yields existence proofs of results without supplying any efficient way of solving the corresponding algorithmic problems. J. Beck has recently found a method for converting some of these existence proofs into efficient algorithmic procedures, at the cost ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An asynchronous two-dimensional self-correcting cellular automaton

    Publication Year: 1991, Page(s):278 - 285
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (760 KB)

    Earlier work of P. Gacs and J. Reif (see J. Comput. Syst. Sci., vol.36, no.2, p.125-147 (1988)) on reliable computation using cellular automata is extended to asynchronous cellular automata. The goal is to find ways to implement computations of arbitrary size by a homogeneous asynchronous array of unreliable elementary components. An asynchronous two-dimensional cellular automaton is constructed s... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optimal file sharing in distributed networks

    Publication Year: 1991, Page(s):515 - 525
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (836 KB)

    Given a distributed network of processors represented by an undirected graph G=(V, E) and a file size k, the problem of distributing an arbitrary file w of k bits among all nodes of the network G is considered. Memory devices are to be assigned to the node of G such that, by accessing the memory of its own and of its adjacent ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Better expansion for Ramanujan graphs

    Publication Year: 1991, Page(s):398 - 404
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (460 KB)

    The expansion properties of regular graphs are investigated. The best previously known expansion of subsets of linear size of explicit k-regular graphs is k/4. This bound is achieved by nonbipartite Ramanujan graphs of degree k=p+1, which have the property that all but the largest eigenvalue have absolute value at most 2√p. The expansion coefficie... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Lower bounds for polynomial evaluation and interpolation problems

    Publication Year: 1991, Page(s):378 - 383
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (392 KB)

    It is shown that there is a set of points p1, p2,. . .,pn such that any algebraic program of depth d for polynomial evaluation (or interpolation) at these points has size Ω(n log n/log d). Moreover, if d is a constant, then a lower bound of Ω(n1+1/d) is obtained View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Faster uniquely represented dictionaries

    Publication Year: 1991, Page(s):642 - 649
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (484 KB)

    The authors present a solution to the dictionary problem where each subset of size n of an ordered universe is represented by a unique structure, containing a (unique) binary search tree. The structure permits the execution of search, insert, and delete operations in O(n1/3) time in the worst case. They also give a general lower bound, stating that for any uni... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A unified geometric approach to graph separators

    Publication Year: 1991, Page(s):538 - 547
    Cited by:  Papers (44)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (688 KB)

    A class of graphs called k-overlap graphs is proposed. Special cases of k-overlap graphs include planar graphs, k-nearest neighbor graphs, and earlier classes of graphs associated with finite element methods. A separator bound is proved for k-overlap graphs embedded in d dimensions. The result unifies several earlier separator results. All the arguments are base... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A quadratic time algorithm for the minmax length triangulation

    Publication Year: 1991, Page(s):414 - 423
    Cited by:  Papers (5)  |  Patents (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (920 KB)

    It is shown that a triangulation of a set of n points in the plane that minimizes the maximum edge length can be computed in time O(n2). The algorithm is reasonably easy to implement and is based on the theorem that there is a triangulation with minmax edge length that contains the relative neighborhood graph of the points as a subgraph. With minor modificatio... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.