Oct. 30 1989Nov. 1 1989
Filter Results

30th Annual Symposium on Foundations of Computer Science (Cat. No.89CH28084)
Publication Year: 1989 PDF (78 KB) 
Testing permutation polynomials
Publication Year: 1989, Page(s):88  92The 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 offtheshelf techniques from computer algebra improve the running time slightly, without requiring any new insights into the problem. A probabilistic variant of the Hermite test that reduces its running time is given. A criterion for per... View full abstract»

The inverse of an automorphism in polynomial time
Publication Year: 1989, Page(s):82  87
Cited by: Papers (1)The first known polynomialtime algorithm for computing the inverse of a
K algebra automorphism is presented. The algorithm works over a commutative ringK and is based on a polynomial decomposition algorithm. A polynomialtime algorithm for computing the left composition factor of a multivariate decomposition is also presented. Two related open problems are stated View full abstract» 
Generalizing the PAC model: sample size bounds from metric dimensionbased uniform convergence results
Publication Year: 1989, Page(s):40  45
Cited by: Papers (19)The probably approximately correct (PAC) model of learning from examples is generalized. The problem of learning functions from a set
X into a setY is considered, assuming only that the examples are generated by independent draws according to an unknown probability measure onX ×Y . The learner's goal is to find a function in a given hypothesis space of fun... View full abstract» 
Structure in locally optimal solutions
Publication Year: 1989, Page(s):216  221
Cited by: Papers (15)A class of local search problems, PLS (polynomialtime local search), as defined by D.S. Johnson et al. (see J. Comput. Syst. Sci., vol.37, no.1, p.79100 (1988)) is considered. PLS captures much of the structure of NP problems at the level of their feasible solutions and neighborhoods. It is first shown that CNF (conjunctive normal form) satisfiability is PLScomplete, even with simultaneously bo... View full abstract»

Full abstraction for nondeterministic dataflow networks
Publication Year: 1989, Page(s):170  175
Cited by: Papers (2)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 inputoutput relation is not compositional. It is shown that the trace semantics is fully abstract for all nondeterministic as well as deterministic networks View full abstract»

Conductance and convergence of Markov chainsa combinatorial treatment of expanders
Publication Year: 1989, Page(s):526  531
Cited by: Papers (23)A direct combinatorial argument is given to bound the convergence rate of Markov chains in terms of their conductance (these are statements of the nature `random walks on expanders converge fast'). In addition to showing that the linear algebra in previous arguments for such results on timereversible Markov chains was unnecessary, the direct analysis applies to general irreversible Markov chains View full abstract»

A randomized maximumflow algorithm
Publication Year: 1989, Page(s):118  123
Cited by: Papers (2)The authors present a randomized maximumflow algorithm, called the PLED (prudent linking excess diminishing) algorithm, whose expected running time is
O (nm +n ^{2}(logn )^{3}); this isO (nm ) for all except relatively sparse networks. The algorithm is always correct, and in the worst case, which occurs with negligible probability... View full abstract» 
An upper bound on the number of planar
Publication Year: 1989, Page(s):72  79k sets
Cited by: Papers (4)Given a set
S ofn points, a subsetX of sizek is called ak set if there is a hyperplane II that separatesX fromX ^{c}. It is proved thatO (n √k /log_{*}k ) is an upper bound for the number ofk sets in the plane, thus improving the previous bound of P. Erdos et al. (A ... View full abstract» 
A theory of learning simple concepts under simple distributions and average case complexity for the universal distribution
Publication Year: 1989, Page(s):34  39
Cited by: Papers (5)It is pointed out that in L.G. Valiant's learning model (Commun. ACM, vol.27, p.113442, 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 notion of learning more closely, it is assumed that learning happens under an arbitrary distribution, rather than under an arbitrary simple distribution... View full abstract»

On the power of 2way probabilistic finite state automata
Publication Year: 1989, Page(s):480  485
Cited by: Papers (3)The recognition power of twoway probabilistic finitestate automata (2PFAs) is studied. It is shown that any 2PFA recognizing a nonregular language must use exponential expected time infinitely often. The power of interactive proof systems (IPSs) where the verifier is a 2PFA is also investigated. It is shown that (1) IPSs in which the verifier uses private randomization are strictly more powerful... View full abstract»

Efficient cryptographic schemes provably as secure as subset sum
Publication Year: 1989, Page(s):236  241
Cited by: Papers (3)Very efficient constructions, based on the intractability of the subset sum problem for certain dimensions, are shown for a pseudorandom generator and for a universal oneway hash function. (Pseudorandom generators can be used for private key encryption, and universal oneway hash functions for signature schemes). The increase in efficiency in the construction is due to the fact that many bits can... View full abstract»

Sorting on a parallel pointer machine with applications to set expression evaluation
Publication Year: 1989, Page(s):190  195
Cited by: Papers (6)Optimal algorithms for sorting on parallel CREW (concurrent read, exclusive write) and EREW (exclusive read, exclusive write) versions of the pointer machine model are presented. Intuitively, these methods can be viewed as being based on the use of linked lists rather than arrays (the usual parallel data structure). It is shown how to exploit the `locality' of the approach to solve a problem with ... View full abstract»

On the complexity of fixed parameter problems
Publication Year: 1989, Page(s):210  215
Cited by: Papers (5)The authors address the question of why some fixedparameter problem families solvable in polynomial time seem to be harder than others with respect to fixedparameter tractability: whether there is a constant α such that all problems in the family are solvable in time
O (n ^{α}). The question is modeled by considering a class of polynomially indexed relations. ... View full abstract» 
A really temporal logic
Publication Year: 1989, Page(s):164  169
Cited by: Papers (48)A realtime 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 to. TPTL is demonstrated to be both a natural specification language and a suitable formalism for verification and synthesis. A tableaubased decis... View full abstract»

Decidability and expressiveness for firstorder logics of probability
Publication Year: 1989, Page(s):148  153
Cited by: Papers (1)Decidability and expressiveness issues for two firstorder 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 reasoning about probability highly undecidable. It is shown that, when the probability is on the domain, if the language contains only unary predicates, t... View full abstract»

Every polynomialtime 1degree collapses iff P=PSPACE
Publication Year: 1989, Page(s):624  629
Cited by: Papers (2)A set
A ism reducible (or Karpreducible) toB if and only if there is a polynomialtime computable functionf such that for allx ,x ∈A if and only iff (x )∈B . Two sets are 1equivalent if each ism reducible to the other by oneone reductions;p invertible equivalent iff each is ... View full abstract» 
On obstructions in relation to a fixed viewpoint
Publication Year: 1989, Page(s):592  597
Cited by: Papers (2)108 Efficient, randomized algorithms are given for the following problems: (1) construction of levels of order 1 to
k in an arrangement of hyperplanes in any dimension; (2) construction of higher order Voronoi diagrams of order 1 tok in any dimension; (3) hidden surface removal for completely general scenes (intersecting and curved faces are allowed). A combinatorial tool in the... View full abstract» 
An analogue of the MyhillNerode theorem and its use in computing finitebasis characterizations
Publication Year: 1989, Page(s):520  525
Cited by: Papers (13)A theorem that is a graphtheoretic analog of the MyhillNerode characterization of regular languages is proved. The theorem is used to establish that for many applications obstruction sets are computable by known algorithms. The focus is exclusively on what is computable (by a known algorithm) in principle, as opposed to what is computable in practice View full abstract»

Simplification of nested radicals
Publication Year: 1989, Page(s):314  319
Cited by: Papers (1)Radical simplification is a fundamental mathematical question, as well as an important part of symbolic computation systems. The general denesting problem had not been known to be decidable. Necessary and sufficient conditions for a radical α over a field
k to be denested, as well as the first algorithm to decide whether the expression can be denested, are given. The algorithm compu... View full abstract» 
Incremental planarity testing
Publication Year: 1989, Page(s):436  441
Cited by: Papers (16)The incremental planarity testing problem consists of performing the following operations on a planar graph
G withn vertices: (1) testing whether a new edge can be added toG so that the resulting graph is itself planar; (2) adding vertices and edges such that planarity is preserved. An efficient technique for incremental planarity testing that usesO (... View full abstract» 
Flow in planar graphs with multiple sources and sinks
Publication Year: 1989, Page(s):112  117
Cited by: Papers (5)  Patents (1)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^{2}n ) time usingO (n ^{1.5}) processors on an exclusivereadexclusivewrite parallel randomaccess machine (EREW PRAM) is obtained, when the amount of flow (demand) at each s... View full abstract» 
Ensemble motion planning in trees
Publication Year: 1989, Page(s):66  71The 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 picked up later, the authors present algorithms for finding a minimum cost transportation that run in
O (k +qn ) time and in... View full abstract» 
Spaceefficient static trees and graphs
Publication Year: 1989, Page(s):549  554
Cited by: Papers (102)  Patents (6)Data structures that represent static unlabeled trees and planar graphs are developed. The structures are more space efficient than conventional pointerbased representations, but (to within a constant factor) they are just as time efficient for traversal operations. For trees, the data structures described are asymptotically optimal: there is no other structure that encodes
n node trees ... View full abstract» 
On the complexity of learning from counterexamples
Publication Year: 1989, Page(s):262  267
Cited by: Papers (12)The complexity of learning concepts belonging to various concrete concept classes
C ⊆2^{X} over a finite domainX is analyzed in terms of the number of counterexamples that are needed in the worst case. It turns out that for many interesting concept classes there exist exponential differences between the number of counterexamples that are required by a `naive' learni... View full abstract»