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

1-4 Oct. 1991

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Displaying Results 1 - 25 of 86
  • Approximating clique is almost NP-complete

    Publication Year: 1991, Page(s):2 - 12
    Cited by:  Papers (81)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (703 KB)

    The computational complexity of approximating omega (G), the size of the largest clique in a graph G, within a given factor is considered. It is shown that if certain approximation procedures exist, then EXPTIME=NEXPTIME and NP=P.<<ETX>> View full abstract»

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  • Fully parallelized multi prover protocols for NEXP-time

    Publication Year: 1991, Page(s):13 - 18
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (482 KB)

    A major open problem in the theory of multiprover protocols is to characterize the languages which can be accepted by fully parallelized protocols which achieve an exponentially low probability of cheating in a single round. The problem was motivated by the observation that the probability of cheating the n parallel executions of a multiprover protocol can be exponentially higher than the probabil... View full abstract»

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  • 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 (793 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 n), yielding the fi... View full abstract»

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  • An optimal convex hull algorithm and new results on cuttings

    Publication Year: 1991, Page(s):29 - 38
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1847 KB)

    An optimal algorithm for computing hyperplane cuttings is given. It results in a new kind of cutting, which enjoys all the properties of the previous ones and, in addition, can be refined by composition. An optimal algorithm for computing the convex hull of a finite point set in any fixed dimension is also given.<<ETX>> View full abstract»

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  • The art gallery theorem for polygons with holes

    Publication Year: 1991, Page(s):39 - 48
    Cited by:  Papers (23)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (589 KB)

    Art gallery problems which have been extensively studied over the last decade ask how to station a small (minimum) set of guards in a polygon such that every point of the polygon is watched by at least one guard. The graph-theoretic formulation and solution to the gallery problem for polygons in standard form is given. A complexity analysis is carried out, and open problems are discussed.<<E... View full abstract»

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  • Fat triangles determine linearly many holes (computational geometry)

    Publication Year: 1991, Page(s):49 - 58
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (723 KB)

    It is shown that for every fixed delta >0 the following holds: if F is a union of n triangles, all of whose angles are at least delta , then the complement of F has O(n) connected components, and the boundary of F consists of O(n log log n) segments. This latter complexity becomes linear if all triangles are of roughly the same size or if they are all infinite wedges. A randomized algorithm tha... View full abstract»

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  • Quantifying knowledge complexity

    Publication Year: 1991, Page(s):59 - 68
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (818 KB)

    Several alternative ways of defining knowledge complexity are presented, and the relationships between them are explored. The discussion covers inclusion results, separation results, properties of knowledge complexity of languages in the Hint sense, and the knowledge complexity of constant round AM proofs.<<ETX>> View full abstract»

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  • Subquadratic zero-knowledge

    Publication Year: 1991, Page(s):69 - 78
    Cited by:  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (870 KB)

    The communication complexity of zero-knowledge proof systems is improved. Let C be a Boolean circuit of size n. Previous zero-knowledge proof systems for the satisfiability of C require the use of Omega (kn) bit commitments in order to achieve a probability of undetected cheating not greater than 2/sup -k/. In the case k=n, the communication complexity of these protocols is therefore Omega (n/sup ... View full abstract»

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  • Simulating BPP using a general weak random source

    Publication Year: 1991, Page(s):79 - 89
    Cited by:  Papers (30)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (925 KB)

    It is shown how to simulate BPP and approximation algorithms in polynomial time using the output from a delta -source. A delta -source is a weak random source that is asked only once for R bits, and must output an R-bit string according to some distribution that places probability no more than 2/sup - delta R/ on any particular string. Also given are two applications: one to show the difficulty of... View full abstract»

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  • Checking the correctness of memories

    Publication Year: 1991, Page(s):90 - 99
    Cited by:  Papers (31)  |  Patents (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (797 KB)

    The notion of program checking is extended to include programs that alter their environment, in particular, programs that store and retrieve data from memory. The model considered allows the checker a small amount of reliable memory. The checker is presented with a sequence of requests (online) to a data structure which must reside in a large but unreliable memory. The data structure is viewed as ... View full abstract»

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  • On-line scheduling in the presence of overload

    Publication Year: 1991, Page(s):100 - 110
    Cited by:  Papers (52)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (856 KB)

    The preemptive scheduling of sporadic tasks on a uniprocessor is considered. A task may arrive at any time, and is characterized by a value that reflects its importance, an execution time that is the amount of processor time needed to completely execute the task, and a deadline by which the task is to complete execution. The goal is to maximize the sum of the values of the completed tasks. An onli... View full abstract»

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  • Dynamic scheduling on parallel machines

    Publication Year: 1991, Page(s):111 - 120
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (775 KB)

    The problem of online job scheduling on various parallel architectures is studied. An O((log log n)/sup 1/2/)-competitive algorithm for online dynamic scheduling on an n*n mesh is given. It is proved that this algorithm is optimal up to a constant factor. The algorithm is not greedy, and the lower bound proof shows that no greedy-like algorithm can be very good. The upper bound result can be gener... View full abstract»

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  • 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
  • Optimal prefetching via data compression

    Publication Year: 1991, Page(s):121 - 130
    Cited by:  Papers (26)  |  Patents (49)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (768 KB)

    A form of the competitive philosophy is applied to the problem of prefetching to develop an optimal universal prefetcher in terms of fault ratio, with particular applications to large-scale databases and hypertext systems. The algorithms are novel in that they are based on data compression techniques that are both theoretically optimal and good in practice. Intuitively, in order to compress data e... View full abstract»

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  • Scheduling parallel machines on-line

    Publication Year: 1991, Page(s):131 - 140
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (826 KB)

    The authors study the problem of scheduling jobs on parallel machines when the existence of a job is not known until an unknown release date and the processing requirement of a job is not known until the job is processed to completion. They demonstrate two general algorithmic techniques for converting existing polynomial-time algorithms that require complete knowledge about the input data into alg... View full abstract»

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  • Concentrated regular data streams on grids: sorting and routing near to the bisection bound

    Publication Year: 1991, Page(s):141 - 150
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (793 KB)

    Sorting and routing on r-dimensional n*. . .*n grids of processors is studied. Deterministic algorithms are presented for h-h problems, h>or=1, where each processor initially and finally contains h elements. It is shown that the classical 1-1 sorting can be solved with (2r-1.5)n+o(n) transport steps, i.e. in about 2.5n steps for r=2. The general h-h sorting problem, h>or=4r-4 can be solved w... View full abstract»

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  • Communication complexity for parallel divide-and-conquer

    Publication Year: 1991, Page(s):151 - 162
    Cited by:  Papers (13)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (883 KB)

    The relationship between parallel computation cost and communication cost for performing divide-and-conquer (D&C) computations on a parallel system of p processors is studied. The parallel computation cost is the maximal number of the D&C nodes that any processor in the parallel system may expand, whereas the communication cost is the total number of cross nodes (nodes generated by one pro... View full abstract»

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  • On selecting a satisfying truth assignment

    Publication Year: 1991, Page(s):163 - 169
    Cited by:  Papers (31)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (517 KB)

    The complexity of certain natural generalizations of satisfiability, in which one of the possibly exponentially many satisfying truth assignments must be selected, is studied. Two natural selection criteria, default preference and minimality (circumscription), are considered. The thrust of the complexity results seems to be that hard problems become harder, while easy problems remain easy. This co... View full abstract»

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  • Exact learning of read-twice DNF formulas

    Publication Year: 1991, Page(s):170 - 179
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (833 KB)

    A polynomial-time algorithm is presented for exactly learning the class of read-twice DNF formulas, i.e. Boolean formulas in disjunctive normal form where each variable appears at most twice. The (standard) protocol used allows the learning algorithm to query whether a given assignment of Boolean variables satisfies the DNF formula to be learned (membership queries), as well as to obtain counterex... View full abstract»

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  • 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 (1620 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»

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  • 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 (888 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»

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  • Reporting points in halfspaces

    Publication Year: 1991, Page(s):207 - 215
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (728 KB)

    The author considers the halfspace range reporting problem: Given a finite set P of points in E/sup d/, preprocess it so that given a query halfspace gamma , the points of p intersection gamma 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 problem. A data structure fo... View full abstract»

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  • 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 (1110 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/sup 3/ is given. The expected running time of the algorithm on a random sequence of updates is close to optimal. Efficient a... View full abstract»

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  • Interactive communication: balanced distributions, correlated files, and average-case complexity

    Publication Year: 1991, Page(s):228 - 238
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (871 KB)

    Suppose (X,Y) is a pair of random variables distributed over a support set S. Person P/sub x/ knows X, person P/sub y/ knows Y, and both know S. Using a predetermined protocol, they exchange binary messages in order for P/sub y/ to learn X. P/sub x/ may or may not learn Y. Bounds on communication complexity are obtained and used to obtain efficient protocols for the correlated files problem where ... View full abstract»

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  • Amortized communication complexity

    Publication Year: 1991, Page(s):239 - 248
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (705 KB)

    The authors study the direct sum problem with respect to communication complexity: Consider a function f: D to (0, 1), where D contained in (0, 1)/sup n/*(0, 1)/sup n/. The amortized communication complexity of f, i.e. the communication complexity of simultaneously computing f on l instances, divided by l is studied. The authors present, both in the deterministic and the randomized model, function... View full abstract»

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