44th Annual IEEE Symposium on Foundations of Computer Science, 2003. Proceedings.

11-14 Oct. 2003

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Displaying Results 1 - 25 of 66
  • Towards a characterization of truthful combinatorial auctions

    Publication Year: 2003, Page(s):574 - 583
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (419 KB) | HTML iconHTML

    This paper analyzes incentive compatible (truthful) mechanisms over restricted domains of preferences, the leading example being combinatorial auctions. Our work generalizes the characterization of Roberts (1979) who showed that truthful mechanisms over unrestricted domains with at least 3 possible outcomes must be "affine maximizers". We show that truthful mechanisms for combinatorial auctions (a... View full abstract»

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  • Towards a dichotomy theorem for the counting constraint satisfaction problem

    Publication Year: 2003, Page(s):562 - 571
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (478 KB) | HTML iconHTML

    The Counting Constraint Satisfaction Problem (#CSP) over a finite domain can be expressed as follows: given a first-order formula consisting of a conjunction of predicates, determine the number of satisfying assignments to the formula. #CSP can be parametrized by the set of allowed constraint predicates. In this paper we start a systematic study of subclasses of #CSP restricted in this way. The ul... View full abstract»

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  • The complexity of homomorphism and constraint satisfaction problems seen from the other side

    Publication Year: 2003, Page(s):552 - 561
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (448 KB) | HTML iconHTML

    We give a complexity theoretic classification of homomorphism problems for graphs and, more generally, relational structures obtained by restricting the left hand side structure in a homomorphism. For every class C of structures, let HOM(C, _) be the problem of deciding whether a given structure A ∈ C has a homomorphism to a given (arbitrary) structure B. We prove that, under some comple... View full abstract»

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  • Linear upper bounds for random walk on small density random 3-CNFs

    Publication Year: 2003, Page(s):352 - 361
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (549 KB) | HTML iconHTML

    We analyze the efficiency of the random walk algorithm on random 3-CNF instances, and prove linear upper bounds on the running time of this algorithm for small clause density, less than 1.63. Our upper bound matches the observed running time to within a multiplicative factor. This is the first sub-exponential upper bound on the running time of a local improvement algorithm on random instances. Our... View full abstract»

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  • On levels in arrangements of curves. II. A simple inequality and its consequences

    Publication Year: 2003, Page(s):544 - 550
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (370 KB) | HTML iconHTML

    We give a surprisingly short proof that in any planar arrangement of n curves where each pair intersects at most a fixed number (s) of times, the k-level has subquadratic (O(n2-12s/)) complexity. This answers one of the main open problems from the author's previous paper, which provided a weaker bound for a restricted class of curves (graphs of degree-s polynomials) only. When combined ... View full abstract»

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  • Performance analysis of dynamic processes

    Publication Year: 2003
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (176 KB) | HTML iconHTML

    The article covers various approaches for modeling and analyzing dynamic processes in networks. Modeling the dynamic performance as a stochastic process, we apply tools from discrete and continuous time Markov processes theory, renewal theory and queuing theory to analyze the long term, steady state performance of the processes. Non-stochastic approaches include adversarial queuing theory, and gam... View full abstract»

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  • Algorithms and complexity results for #SAT and Bayesian inference

    Publication Year: 2003, Page(s):340 - 351
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (403 KB) | HTML iconHTML

    Bayesian inference is an important problem with numerous applications in probabilistic reasoning. Counting satisfying assignments is a closely related problem of fundamental theoretical importance. In this paper, we show that plain old DPLL equipped with memorization (an algorithm we call #DPLLCache) can solve both of these problems with time complexity that is at least as good as state-of-the-art... View full abstract»

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  • Separating the power of monotone span programs over different fields

    Publication Year: 2003, Page(s):428 - 501
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (605 KB) | HTML iconHTML

    Monotone span programs are a linear-algebraic model of computation. They are equivalent to linear secret sharing schemes and have various applications in cryptography and complexity. A fundamental question is how the choice of the field in which the algebraic operations are performed effects the power of the span program. In this paper we prove that the power of monotone span programs over finite ... View full abstract»

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  • Bounded geometries, fractals, and low-distortion embeddings

    Publication Year: 2003, Page(s):534 - 543
    Cited by:  Papers (50)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (386 KB) | HTML iconHTML

    The doubling constant of a metric space (X, d) is the smallest value λ such that every ball in X can be covered by λ balls of half the radius. The doubling dimension of X is then defined as dim (X) = log2λ. A metric (or sequence of metrics) is called doubling precisely when its doubling dimension is bounded. This is a robust class of metric spaces which contains man... View full abstract»

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  • Mixing [Markov chain]

    Publication Year: 2003, Page(s):4 - 15
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB) | HTML iconHTML

    In this paper, we introduce the notion of a Markov chain and explore how it can be used to sample from a large set of configurations. Our primary focus is determining how quickly a Markov chain "mixes," or converges to its stationary distribution, as this is the key factor in the running time. We provide an overview of several techniques used to establish good bounds on the mixing time. The applic... View full abstract»

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  • On certain connectivity properties of the Internet topology

    Publication Year: 2003, Page(s):28 - 35
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (433 KB) | HTML iconHTML

    We show that random graphs in the preferential connectivity model have constant conductance, and hence have worst-case routing congestion that scales logarithmically with the number of nodes. Another immediate implication is constant spectral gap between the first and second eigenvalues of the random walk matrix associated with these graphs. We also show that the expected frugality (overpayment in... View full abstract»

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  • Approximation algorithms for orienteering and discounted-reward TSP

    Publication Year: 2003, Page(s):46 - 55
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (331 KB) | HTML iconHTML

    In this paper, we give the first constant-factor approximation algorithm for the rooted orienteering problem, as well as a new problem that we call the Discounted-Reward TSP, motivated by robot navigation. In both problems, we are given a graph with lengths on edges and prizes (rewards) on nodes, and a start node s. In the orienteering problem, the goal is to find a path that maximizes the reward ... View full abstract»

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  • The resolution complexity of random constraint satisfaction problems

    Publication Year: 2003, Page(s):330 - 339
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (569 KB) | HTML iconHTML

    We consider random instances of constraint satisfaction problems where each variable has domain size d, and each constraint contains t restrictions on k variables. For each (d, k, t) we determine whether the resolution complexity is a.s. constant, polynomial or exponential in the number of variables. For a particular range of (d, k, t) we determine a sharp threshold for resolution complexity where... View full abstract»

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  • On worst-case to average-case reductions for NP problems

    Publication Year: 2003, Page(s):308 - 317
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (345 KB) | HTML iconHTML

    We show that if an NP-complete problem has a non-adaptive self-corrector with respect to a distribution that can be sampled then coNP is contained in AM/poly and the polynomial hierarchy collapses to the third level. Feigenbaum and Fortnow show the same conclusion under the stronger assumption that an NP-complete problem has a non-adaptive random self-reduction. Our result shows it is impossible (... View full abstract»

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  • Symmetric polynomials over Zm and simultaneous communication protocols

    Publication Year: 2003, Page(s):450 - 459
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (560 KB) | HTML iconHTML

    We study the problem of representing symmetric Boolean functions as symmetric polynomials over Zm. We show an equivalence between such representations and simultaneous communication protocols. Computing a function f on 0 - 1 inputs with a polynomial of degree d modulo pq is equivalent to a two player simultaneous protocol for computing f where one player is given the first [logp View full abstract»

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  • Hardness of approximating the shortest vector problem in high Lp norms

    Publication Year: 2003, Page(s):290 - 297
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (474 KB) | HTML iconHTML

    We show that for every ε > 0, there is a constant p(ε) such that for all integers p ≥ p(ε), it is NP-hard to approximate the shortest vector problem in Lp norm within factor p1 - ε under randomized reductions. For large values of p, this improves the factor 21p/ - δ hardness shown by D. Micciancio (1998). View full abstract»

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  • Solving sparse, symmetric, diagonally-dominant linear systems in time O(m1.31

    Publication Year: 2003, Page(s):416 - 427
    Cited by:  Papers (6)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (687 KB) | HTML iconHTML

    We present a linear-system solver that, given an n-by-n symmetric positive semi-definite, diagonally dominant matrix A with m non-zero entries and an n-vector b, produces a vector x˜ within relative distance ε of the solution to Ax = b in time O(m1.31log(n/ε)bO(1)), where b is the log of the ratio of the largest to smallest non-zero entry of A. If the graph of... View full abstract»

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  • Simulated annealing in convex bodies and an O*(n4) volume algorithm

    Publication Year: 2003, Page(s):650 - 659
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (522 KB) | HTML iconHTML

    We present a new algorithm for computing the volume of a convex body in Rn. The main ingredient of the algorithm is a "morphing" technique that can be viewed as a variant of simulated annealing. Its complexity is O*(n4), improving on the previous best algorithm by a factor of n. View full abstract»

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  • Clustering with qualitative information

    Publication Year: 2003, Page(s):524 - 533
    Cited by:  Papers (26)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (342 KB) | HTML iconHTML

    We consider the problem of clustering a collection of elements based on pairwise judgments of similarity and dissimilarity. N. Bansal et al. (2002) cast the problem thus: given a graph G whose edges are labeled "+" (similar) or "-" (dissimilar), partition the vertices into clusters so that the number of pairs correctly (resp. incorrectly) classified with respect to the input labeling is maximized ... View full abstract»

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  • The cost of cache-oblivious searching

    Publication Year: 2003, Page(s):271 - 282
    Cited by:  Papers (5)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (387 KB) | HTML iconHTML

    Tight bounds on the cost of cache-oblivious searching are proved. It is shown that no cache-oblivious search structure can guarantee that a search performs fewer than lg e logBN block transfers between any two levels of the memory hierarchy. This lower bound holds even if all of the block sizes are limited to be powers of 2. A modified version of the van Emde Boas layout is proposed, wh... View full abstract»

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  • General composition and universal composability in secure multi-party computation

    Publication Year: 2003, Page(s):394 - 403
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (342 KB) | HTML iconHTML

    Concurrent general composition relates to a setting where a secure protocol is run in a network concurrently with other, arbitrary protocols. Clearly, security in such a setting is what is desired, or even needed, in modern computer networks where many different protocols are executed concurrently. Our main result is a proof that security under concurrent general composition is equivalent to a rel... View full abstract»

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  • The Ising model on trees: boundary conditions and mixing time

    Publication Year: 2003, Page(s):628 - 639
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (723 KB) | HTML iconHTML

    We give the first comprehensive analysis of the effect of boundary conditions on the mixing time of the Glauber dynamics for the Ising model. Specifically, we show that the mixing time on an n-vertex regular tree with (+) boundary remains O(n log n) at all temperatures (in contrast to the free boundary case, where the mixing time is not bounded by any fixed polynomial at low temperatures). We also... View full abstract»

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  • Switch scheduling via randomized edge coloring

    Publication Year: 2003, Page(s):502 - 512
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (442 KB) | HTML iconHTML

    The essence of an Internet router is an n × n switch which routes packets from input to output ports. Such a switch can be viewed as a bipartite graph with the input and output ports as the two vertex sets. Packets arriving at input port i and destined for output port j can be modeled as an edge from i to j. Current switch scheduling algorithms view the routing of packets at each time step a... View full abstract»

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  • Breaking a time-and-space barrier in constructing full-text indices

    Publication Year: 2003, Page(s):251 - 260
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (501 KB) | HTML iconHTML

    Suffix trees and suffix arrays are the most prominent full-text indices, and their construction algorithms are well studied. It has been open for a long time whether these indices can be constructed in both O(n log n) time and O(n log n)-bit working space, where n denotes the length of the text. In the literature, the fastest algorithm runs in O(n) time, while it requires O(n log n)-bit working sp... View full abstract»

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  • Quantum search of spatial regions

    Publication Year: 2003, Page(s):200 - 209
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1040 KB) | HTML iconHTML

    Can Grover's quantum search algorithm speed up search of a physical region - for example a 2D grid of size √n x √n? The problem is that √n time seems to be needed for each query, just to move amplitude across the grid. Here we show that this problem can be surmounted, refuting a claim to the contrary by Benioff. In particular, we show how to search a d-dimensional hypercube in ti... View full abstract»

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