Showing papers in "Journal of Computer and System Sciences in 1997"

TL;DR: This work presents anO(m) time randomized (Monte Carlo) algorithm that estimates, with small relative error, the sizes of all reachability sets and the transitive closure.

TL;DR: In this article, the authors proved the following about the Nearest Lattice Vector Problem (NLPV) and the NLPV problem for binary codes: the problem of learning a half-space in the presence of errors, and the problems of finding the nearest code word for any binary code.

TL;DR: The strong learning algorithm utilizes one of Freund's boosting techniques and relies on the fact that boosting does not require a completely distribution-independent weak learner, and it is shown that DNF is weakly learnable with respect to uniform from noisy examples.

TL;DR: A new method is introduced for proving explicit upper bounds on the VC dimension of general functional basis networks and it is proved as an application, for the first time, that theVC dimension of analog neural networks with the sigmoidal activation function is bounded by a quadratic polynomialO((lm)2) in both the numberlof programmable parameters, and the numbermof nodes.

TL;DR: Theoretical foundations for querying databases based on bags, and the expressive power of BQL and related languages, are investigated in depth and it is proved that these languages possess the conservative extension property.

TL;DR: It is shown that an NP optimization problem is fixed-parameter tractable if it admits a fully polynomial-time approximation scheme, or if it belongs to the class MAX SNP or to theclass MIN F+?1, providing strong evidence that noW1-hard NP optimization problems belong to these optimization classes.

TL;DR: It is shown that in this context queries are intractable even under the data complexity measure, but identify a number of PTIME subproblems.

TL;DR: It is shown that ORD is L-complete (via quantifier-free projections), and there are no pseudo-sparse NP-complete properties unless the polynomial time hierarchy collapses (to?3), revealing a structural property on which L and NP apparently differ.

TL;DR: It is shown that neural networks which use continuous activation functions have VC dimension at least as large as the square of the number of weightsw, which settles a long-standing open question.

TL;DR: In this article, the authors study infinite but finitely representable databases based on constraints, motivated by new database applications such as those involving spatio-temporal information, and illustrate the use of Ehrenfeucht?Frai?sse games on the expressive power of query languages over finite databases.

TL;DR: A non-deterministic semantics is also proposed for total stable models and its expressive power is fully characterized as well.

TL;DR: This work forms a minimal model of a program component including aggregate operators, rather than insisting that the aggregate apply to atoms that have been fully determined or that aggregate functions are rewritten in terms of negation, based on a notion of minimality.

TL;DR: This work studies the problem of determining whether a given recursive Datalog program is equivalent to a given nonrecursive Datalogs program, and proves triply exponential upper and lower time bounds for this problem.

TL;DR: It is proved that certain standard complete problems for static complexity classes, such as REACHafor P, remain complete via these new reductions, and that other such problems, including REACH for NL and REACHdfor L, are no longer complete via bounded-expansion reductions.

TL;DR: The best asymptotic bound known so far is O(nlogn·min{n,nlogC{, wheren=|V| andC=?a?Aca].

TL;DR: An interactive model in which the learner has the ability to ask queries as in the query learning model of Angluin is presented, and it is shown that anything learnable with queries, even by a randomized learner, is teachable in this model.

TL;DR: It is proved that only an amortized constant amount of rebalancing is necessary after an update in a chromatic search tree, and it is shown that the amount ofRebalancing done at any particular level decreases exponentially, going from the leaves toward the root.

TL;DR: This work provides the first analysis of R-trees for skewed distributions of points, and develops a formula that estimates the number of disk accesses for range queries, given only the fractal dimension of the point set and its count.

TL;DR: A weak version of the Blum?Shub?Smale model of computation over the real numbers, where only a “moderate” usage of multiplications and divisions is allowed, and the class of boolean languages recognizable in polynomial time is shown to be the complexity class P/poly.

TL;DR: This paper provides the first parallel parallel (NC) algorithm for constructing a compact distribution that satisfies the constraints up to a small relative error and suggests new proof techniques which might be useful in general probabilistic analysis.

TL;DR: It is shown that the class of sets that Turing reduce to hasp2-measure 0 (therefore, measure 0 inEXP), giving a natural example of a language that is not weakly complete forEXPand that reduces to a measure 0 class inEXP.

TL;DR: The following theorem is proved that there exists a solution of the Steiner tree problem such that all Steiner points are on the intersections of grid lines formed by passing lines at directionsi?/2,i=0,1, through all demand points.

TL;DR: Sharpupper bounds are obtained for the complexity of the most difficultn-variable function over certain bases and explicit nonlinear lower bounds for the formula sizeof analog circuits over bases containing addition, subtraction, multiplication, the sign function and all real constants are proved.

TL;DR: A direct, polynomial-time analog of effective operation in which the time bounding on computations is modeled after Kapron and Cook's scheme for their basic polynometric-time functionals is developed.

TL;DR: The aim of this paper is to prove that if if L is a context-free language, then the language Min(L) context- free.

TL;DR: A model of gate failure for Boolean circuits in which a faulty gate is restricted to output one of its input values, which allows Boolean circuits that can tolerate worst-case faults, as well as circuits that have arbitrarily high success probability in the case of random faults to be designed.

TL;DR: This paper investigates global states shared by all such observations, and an algorithm that computes shared global states is described that accepts several consistent observations.

TL;DR: Borders suggest the possibility that even relatively low levels of the polynomial hierarchy cannot be accepted via large numbers of simple tasks that can be scheduled arbitrarily, and show that the class of languages so accepted is exactly NPPP.

TL;DR: It is proved that fixed subgraph homeomorphism queries require width of recursively defined predicates which is at least equal to the number of arcs in the pattern graph.

TL;DR: An oracle relative to which there are one-way functions but every paddable 1-li-degree collapses to an isomorphism type is demonstrated, thus yielding a relativized failure of the Joseph?Young Conjecture.