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A general framework is developed for removing randomness from randomized NC algorithms whose analysis uses only polylogarithmic independence. Previously, no techniques were known to determinize those RNC algorithms depending on more than constant ...

A method is provided for converting randomized parallel algorithms into deterministic parallel algorithms. The approach is based on a parallel implementation of the method of conditional probabilities. Results obtained by applying the method to the set ...

The use of highly expanding bipartite multigraphs (called dispersers) to reduce greatly the error of probabilistic algorithms at the cost of few additional random bits is treated. Explicit constructions of such graphs are generalized and used to obtain ...

A mechanism is provided for constructing log-n-wise-independent hash functions that can be evaluated in O(1) time. A probabilistic argument shows that for fixed epsilon <1, a table of n/sup epsilon / random words can be accessed by a small O(1)-time ...

The problem of improving the accuracy of a hypothesis output by a learning algorithm in the distribution-free learning model is considered. A concept class is learnable (or strongly learnable) if, given access to a source of examples from the unknown ...

It is pointed out that in L.G. Valiant's learning model (Commun. ACM, vol.27, p.1134-42, 1984) many concepts turn out to be too hard to learn, whereas in practice, almost nothing we care to learn appears to be not learnable. To model the intuitive ...

The probably approximately correct (PAC) model of learning from examples is generalized. The problem of learning functions from a set X into a set Y is considered, assuming only that the examples are generated by independent draws according to an ...

The problem of designing polynomial prediction algorithms for learning binary relations is studied for an online model in which the instances are drawn by the learner, by a helpful teacher, by an adversary, or according to a probability distribution on ...

NC approximation algorithms are given for the unweighted and weighted set cover problems. The algorithms use a linear number of processors and give a cover that has at most log n times the optimal size/weight, thus matching the performance of the best ...

The complete graph induced by a set of 2n points on the boundary of a polygon is considered. The edges are assigned weights equal to the Euclidean distance between their endpoints if the endpoints see each other in the polygon, and + infinity otherwise. ...

The problem of transporting a set of objects between the vertices of a tree by a unit capacity vehicle that travels along the edges of the tree is considered. For the case in which any object can be dropped at intermediate vertices along its route and ...

Given a set S of n points, a subset X of size k is called a k-set if there is a hyperplane II that separates X from X/sup c/. It is proved that O(n square root k/log/sub */k) is an upper bound for the number of k-sets in the plane, thus improving the ...

The first known polynomial-time algorithm for computing the inverse of a K-algebra automorphism is presented. The algorithm works over a commutative ring K and is based on a polynomial decomposition algorithm. A polynomial-time algorithm for computing ...

The simple test for determining whether an arbitrary polynomial is a permutation polynomial, by producing its list of values, is considered, and it is found that off-the-shelf techniques from computer algebra improve the running time slightly, without ...

The bit complexity of computing irreducible representations of finite groups is considered. Exact computations in algebraic number fields are performed symbolically. A polynomial-time algorithm for finding a complete set of inequivalent irreducible ...

Let p be a prime and F be a polynomial with integer coefficients. Suppose that the discriminant of F is not divisible by p, and denote by m the degree of the splitting field of F over Q and by L the maximal size of the coefficients of F. Then, assuming ...

Efficient algorithms are presented for the matroid intersection problem and generalizations. The algorithm for weighted intersection works by scaling the weights. The cardinality algorithm is a special case that takes advantage of greater structure. ...

Given a planar network with many sources and sinks, the problem of computing the maximum flow from the sources to the sinks is investigated. An algorithm that runs in O(log/sup 2/n) time using O(n/sup 1.5/) processors on an exclusive-read-exclusive-...

The authors present a randomized maximum-flow algorithm, called the PLED (prudent linking excess diminishing) algorithm, whose expected running time is O(nm+n/sup 2/(log n)/sup 3/); this is O(nm) for all except relatively sparse networks. The algorithm ...

The problem of computing the chromatic number of a graph is considered. No known approximation algorithm can guarantee a better than O(n/sup 0.4/) coloring on a three-chromatic graph with n vertices. Evidence is provided that it is inherently impossible ...

An instance of the stable marriage problem of size n involves n men and n women. Each participant ranks all members of the opposite sex in order of preference. A stable marriage is a complete matching M=((m/sub 1/, w/sub i1/), (m/sub 2/, w/sub i2/), . . ...

Several constrained scheduling problems are considered. The first polynomial approximation schemes for the problem of minimizing maximum completion time in a two-machine flow shop with release dates and for the problem of minimizing maximum lateness for ...

The relation between the expressive power of datalog and that of first-order languages, is clarified. It is then proved that every first-order expressible datalog query is bounded. A form of compactness theorem for finite structure implied by this ...

Decidability and expressiveness issues for two first-order logics of probability are considered. In one the probability is on possible worlds, whereas in the other it is on the domain. It turns out that in both cases it takes very little to make ...

The authors define a simple typed while-programming language that generalizes the sort of simple language used in computability texts to define the familiar numerical computable functions and corresponds roughly to the mu -recursion of R.O. Gandy (1967)...

P. Kolaitis and M. Vardi (see Proc. 19th ACM Symp. on Theory of Computing, p.425-35 (1987), and Proc. 3rd Ann. Symp. on Logic in Computer Science, p.2-11 (1988)) proved that the 0-1 law holds for the second-order existential sentences whose first-order ...

A real-time temporal logic for the specification of reactive systems is introduced. The novel feature of the logic, TPTL, is the adoption of temporal operators as quantifiers over time variables; every modality binds a variable to the time(s) it refers ...

The problem of finding fully abstract semantic models for nondeterministic dataflow networks is discussed. The author presents a result indicating that there exist nondeterministic networks using only bounded choice for which the input-output relation ...

A classic open problem on tree pattern matching is whether the naive O(mn)-step algorithm for finding all the occurrences of a pattern tree of size m in a text tree of size n can be improved. An O(nM/sup 0.75/ polylog(m))-step algorithm for this tree ...