# Proceedings., 33rd Annual Symposium on Foundations of Computer Science

## Filter Results

Displaying Results 1 - 25 of 78
• ### Proceedings 33rd Annual Symposium on Foundations of Computer Science (Cat. No.92CH3188-0)

Publication Year: 1992
| |PDF (83 KB)
• ### Dynamic half-space reporting, geometric optimization, and minimum spanning trees

Publication Year: 1992, Page(s):80 - 89
Cited by:  Papers (17)
| |PDF (732 KB)

The authors describe dynamic data structures for half-space range reporting and for maintaining the minima of a decomposable function. Using these data structures, they obtain efficient dynamic algorithms for a number of geometric problems, including closest/farthest neighbor searching, fixed dimension linear programming, bi-chromatic closest pair, diameter, and Euclidean minimum spanning tree View full abstract»

• ### Randomized geometric algorithms and pseudo-random generators

Publication Year: 1992, Page(s):90 - 100
Cited by:  Papers (2)
| |PDF (896 KB)

The so called randomized incremental algorithms in computational geometry can be thought of as a generalization of Quicksort to higher dimensional geometric problems. They all construct the geometric complex in the given problem, such as a Voronoi diagram or a convex polytope, by adding the objects in the input set, one at a time, in a random order. The author shows that the expected running times... View full abstract»

• ### Drawing planar graphs using the lmc-ordering

Publication Year: 1992, Page(s):101 - 110
Cited by:  Papers (3)
| |PDF (772 KB)

The author introduces a method to optimize the required area, minimum angle and number of bends of planar drawings of graphs on a grid. The main tool is a new type of ordering on the vertices and faces of triconnected planar graphs. With this method linear time and space algorithms can be designed for many graph drawing problems. He shows that every triconnected planar graph G can be drawn convexl... View full abstract»

• ### Exact analysis of hot-potato routing

Publication Year: 1992, Page(s):553 - 562
Cited by:  Papers (22)  |  Patents (1)
| |PDF (776 KB)

The authors consider a form of packet routing known as hot potato routing or deflection routing. Its striking feature is that there are no buffers at intermediate nodes. Thus packets are always moving (possibly in the wrong' direction), giving rise to the term hot potato'. They give a simple deterministic algorithm that on a n×n torus will route a random instance in 2 View full abstract»

• ### Computing in solvable matrix groups

Publication Year: 1992, Page(s):111 - 120
Cited by:  Papers (9)
| |PDF (860 KB)

The author announces methods for efficient management of solvable matrix groups over finite fields. He shows that solvability and nilpotence can be tested in polynomial-time. Such efficiency seems unlikely for membership-testing, which subsumes the discrete-log problem. However, assuming that the primes in |G| (other than the field characteristic) are polynomially-bounded, membership-testing and m... View full abstract»

• ### A theory of wormhole routing in parallel computers

Publication Year: 1992, Page(s):563 - 572
Cited by:  Papers (14)
| |PDF (744 KB)

Virtually all theoretical work on message routing in parallel computers has dwelt on packet routing: messages are conveyed as packets, an entire packet can reside at a node of the network, and a packet is sent from the queue of one node to the queue of another node until its reaches its destination. The current trend in multicomputer architecture, however, is to use wormhole routing. In wormhole r... View full abstract»

• ### Fast algorithms for matrix normal forms

Publication Year: 1992, Page(s):121 - 130
Cited by:  Papers (1)
| |PDF (720 KB)

A Las Vegas type probabilistic algorithm is presented for computing the Frobenius normal form of an n×n matrix T over any field K. The algorithm requires O~(MM(n))=MM(n).(log n)O(1) operations in K, where O(MM(n)) operations in K are sufficient to multiply two n×n matrices over K. This nearly matches the lower bound of Ω(MM(n)) operations in K for... View full abstract»

• ### Computing a shortest k-link path in a polygon

Publication Year: 1992, Page(s):573 - 582
Cited by:  Papers (7)
| |PDF (756 KB)

The authors consider the problem of finding a shortest polygonal path from s to t within a simple polygon P, subject to the restriction that the path have at most k links (edges). They give an algorithm to compute a k-link path with length at most (1 + ε) times the length of a shortest k-link path, for any error tolerance ε>0. The algorithm runs in time O(n3k3 lo... View full abstract»

• ### Improved parallel polynomial division and its extensions

Publication Year: 1992, Page(s):131 - 136
Cited by:  Patents (1)
| |PDF (404 KB)

The authors compute the first N coefficients of the reciprocal r(x) of a given polynomial p(x), (r(x)p(x)=1 mod xN, p(0)≠0), by using, under the PRAM arithmetic models, O(h log N) time-steps and O((N/h)(1+2-hlog(h) N)) processors, for any h, h=1,2, . . .,log* N, provided that O(logm) steps and m processors suffice to perform DFT on m points and that l... View full abstract»

• ### Efficient minimum cost matching using quadrangle inequality

Publication Year: 1992, Page(s):583 - 592
Cited by:  Papers (2)
| |PDF (768 KB)

The authors present efficient algorithms for finding a minimum cost perfect matching, and for solving the transportation problem in bipartite graphs, G = (Red ∪ Blue, Red × Blue), where |Red| = n, |Blue| = m, n ⩽ m, and the cost function obeys the quadrangle inequality. The first results assume that all the red points and all the blue points lie on a curve that is homeomorphic to eit... View full abstract»

• ### Randomized consensus in expected O(n log2 n) operations per processor

Publication Year: 1992, Page(s):137 - 146
| |PDF (776 KB)

The paper presents a new randomized algorithm for achieving consensus among asynchronous processors that communicate by reading and writing shared registers. The fastest previously known algorithm requires a processor to perform an expected O(n2 log n) read and write operations in the worst case. In the algorithm, each processor executes at most an expected <... View full abstract»

• ### Fault-tolerant wait-free shared objects

Publication Year: 1992, Page(s):157 - 166
Cited by:  Papers (5)  |  Patents (1)
| |PDF (728 KB)

The authors classify object failures into two broad categories: responsive and non-responsive. They require that wait-free objects subject to responsive failures continue to respond (in finite time) to operation invocations. The responses may be incorrect. In contrast, wait-free objects subject to non-responsive failures are exempt from responding to operation invocations. Such objects may hang' ... View full abstract»

• ### Optimal parallel hull construction for simple polygons in O(log log n) time

Publication Year: 1992, Page(s):593 - 599
| |PDF (556 KB)

The author proposes an optimal parallel algorithm for computing the convex hull of a simple polygon. The algorithm achieves a runtime of O(log log n) using O(n/log log n) processors of a CRCW-PRAM. The data structure representing the convex hull is not the standard one, i.e. an array storing the vertices of the hull in clockwise order. Indeed, a lower bound of Ω(log n/log log n) on the runti... View full abstract»

• ### Zero-knowledge proofs of knowledge without interaction

Publication Year: 1992, Page(s):427 - 436
Cited by:  Papers (12)
| |PDF (776 KB)

A zero-knowledge proof system of knowledge is a protocol between two parties called the prover and the verifier. The prover wants to convince the verifier that he knows' the proof of a given theorem without revealing any additional information. This is different from a zero-knowledge proof system of membership where the prover convinces the verifier only of the veridicity of the statement. Zero-k... View full abstract»

• ### Hierarchies in transitive closure logic, stratified Datalog and infinitary logic

Publication Year: 1992, Page(s):167 - 176
Cited by:  Papers (1)
| |PDF (732 KB)

The authors establish a general hierarchy theorem for quantifier classes in the infinitary logic L∞ωω on finite structures. In particular, it is shown that no infinitary formula with bounded number of universal quantifiers can express the negation of a transitive closure. This implies the solution of several open problems in finite model theory: On finite s... View full abstract»

• ### On the exact learning of formulas in parallel

Publication Year: 1992, Page(s):513 - 522
Cited by:  Papers (3)
| |PDF (692 KB)

The authors investigate the parallel complexity of learning formulas from membership and equivalence queries. They consider a number of learning problems that can be solved sequentially in polynomial time. They prove some upper and lower bounds on the number of parallel steps required to solve these problems with a polynomial number of processors View full abstract»

• ### Tighter bounds on the exact complexity of string matching

Publication Year: 1992, Page(s):600 - 609
Cited by:  Papers (5)
| |PDF (860 KB)

The paper considers how many character comparisons are needed to find all occurrences of a pattern of length m in a text of length n. The main contribution is to show an upper bound of the form n + O(n/m) character comparisons, following preprocessing. Specifically, the authors show an upper bound of n+8/3(m+1)(n-m) character comparisons. This bound is achieved by an online algorithm which perform... View full abstract»

• ### On the bit extraction problem

Publication Year: 1992, Page(s):314 - 319
Cited by:  Papers (18)
| |PDF (412 KB)

Consider a coloring of the n-dimensional Boolean cube with c=2s colors in such a way that every k-dimensional subcube is equicolored, i.e. each color occurs the same number of times. The author shows that for such a coloring one necessarily has (k-1)/n⩾θ c=(c/2-1)/(c-1). This resolves the bit extraction' or t-resilient functions' problem (also a special case of th... View full abstract»

• ### Fast unimodular reduction: planar integer lattices

Publication Year: 1992, Page(s):437 - 446
Cited by:  Papers (1)
| |PDF (580 KB)

The author shows that a shortest basis for the 2-dimensional lattice Λ(u, v) generated by an input pair u, v∈Z 2 can be computed in O(M(n) log n) where n is the bit-size of the input numbers and M(n) is the complexity of multiplying two n-bit integers. This generalizes Schonhage's technique (1971) for fast integer GCD to a higher dimension View full abstract»

• ### Back to the future: towards a theory of timed regular languages

Publication Year: 1992, Page(s):177 - 186
Cited by:  Papers (7)
| |PDF (772 KB)

The authors introduce two-way timed automata-timed automata that can move back and forth while reading a timed word. Two-wayness in its unrestricted form leads, like nondeterminism, to the undecidability of language inclusion. However, if they restrict the number of times an input symbol may be revisited, then two-wayness is both harmless and desirable. The authors show that the resulting class of... View full abstract»

• ### On the completeness of object-creating query languages

Publication Year: 1992, Page(s):372 - 379
Cited by:  Papers (3)
| |PDF (556 KB)

Recently, various database query languages have been considered that have the ability to create new domain elements. These languages, however, are not complete in the sense of Abiteboul and Kanellakis (1989). They provide a precise characterization for the class of queries that can be expressed in these languages. They call this class the constructive queries and motivate this term by establishing... View full abstract»

• ### The complexity of parallel prefix problems on small domains

Publication Year: 1992, Page(s):638 - 647
Cited by:  Papers (4)
| |PDF (660 KB)

The authors study the complexity of some prefix problems in the CRCW PRAM model. The main result is an Ω(α(n)) lower bound for chaining, matching a previous upper bound and solving an open problem. They give reductions to show an Ω(α(n)) lower bound on the complexity of the prefix maxima and range maxima problems even when the domain is {1,...,n}. An interesting consequence... View full abstract»

• ### Fully dynamic biconnectivity in graphs

Publication Year: 1992, Page(s):50 - 59
Cited by:  Papers (5)
| |PDF (852 KB)

The author presents an algorithm for maintaining the bi-connected components of a graph during a sequence of edge insertions and deletions. It requires linear storage and preprocessing time. The amortized running time for insertions and for deletions is O(m2/3 ), where m is the number of edges in the graph. Each query of the form `Are the vertices u and v biconnected?' can be answered i... View full abstract»

• ### Read-thrice DNF is hard to learn with membership and equivalence queries

Publication Year: 1992, Page(s):523 - 532
Cited by:  Papers (7)
| |PDF (860 KB)

A general technique is developed to obtain nonlearnability results in the model of exact learning from equivalence and membership queries. The technique is applied to show that, assuming NP≠co-NP, there does not exist a polynomial-time membership and equivalence query algorithm for exactly learning read-thrice DNF formulas-boolean formulas in disjunctive normal form where each variable appears ... View full abstract»