Showing papers in "Information Processing Letters in 1989"

TL;DR: A 4 3 -approximation algorithm is given for the special case in which the underlying network is complete and all edge lengths are either 1 or 2, showing that this special case is MAX SNP-hard, which may be evidence that the Steiner problem on networks has no polynomial-time approximation scheme.

TL;DR: The method can be used to compute the upper envelope of “segments” that intersect pairwise at most k times and computes theupper envelope in O(λk + 1(n)log n) time.

TL;DR: An O(n log n) time algorithm to find an optimal ranking of an n-node tree is described.

TL;DR: The expected number of maximal vectors explicitly for any n and d is determined and the asymptotic behaviour of this quantity as n tends to infinity follows immediately from this result.

TL;DR: A new, yet very simple principle for global quiescence detection, where all active processes and all messages of the underlying computation have a share of a credit initially distributed by the environment.

TL;DR: It is proved that the Achromatic Number problem is NP-complete when restricted to connected graphs that are simultaneously a cograph and an interval graph.

TL;DR: Very simple optimal EREW PRAM algorithms for the tasks of sorting n elements and of merging two sorted sequences of total length n are described, achieving running times that are within lower-order terms of the minimum achievable.

TL;DR: It is shown how automatically specializing a fairly naive pattern matcher by partial evaluation leads to the Knuth, Morris & Pratt algorithm, a deterministic finite automaton.

TL;DR: It is shown that a perfect elimination scheme of a chordal graph can be computed in O(log n ) time with O( n 3 ) processors on CRCW PRAM once a clique tree of the graph is given.

TL;DR: The algorithm for distributed mutual exclusion is extended to enable up to K nodes to be within the critical section simultaneously and requires at most 2 * (N-1) messages per entry to thecritical section, and occasionally fewer.

TL;DR: An algorithm which, given a tree-realizable distance matrix, constructs the tree in optimal O ( n 2 ) time is presented and it is shown how the algorithm can be used to test tree- realizability of a distance matrix.

TL;DR: A new threshold scheme is presented, which is based on the definition of cross-product in an N -dimensional vector space, which provides a protection of property against problems such as abnegation incidents or betrayal incidents.

TL;DR: This work disproves a conjecture by Ibarra and Jiang that proposes a candidate for showing that the class of languages accepted in real-time by one-way cellular arrays (OCA) is not closed under concatenation and shows that their candidate and also similar languages are accepted by OCA in real time.

TL;DR: A new elementary reduction of two- way automata to one-way automata is described, based on the subset construction rather than on crossing sequence analysis.

TL;DR: A new approach to SMk is followed based on the determination of the permutations of P in T, and two algorithms for its solution are proposed, which make use of a suffix tree.

TL;DR: It is shown that the problem of finding Hamiltonian circuits in intersection graphs of chords in a circle is NP-complete.

TL;DR: The above equation is used as the definition of Hausdorff distance: the distance between pixels (xl, yl) and (x2, y2) is defined by the L1 or “Manhattan” metric.

TL;DR: A proof of the fact that determining whether or not a given binary tree has a grid embedding with edges of unit length is an NP-complete problem is given.

TL;DR: The sequential depth-first-search algorithm, distributed over processor nodes of a graph, yields a distributed depth- first- search algorithm that uses exactly 2| V | messages and 2 | V | units of time.

TL;DR: It is proved that boundedness is undecidable even for Datalog programs with a single recursive rule, which strengthens the undecidability results of Gaifman et al. (1987) for multiple recursive rule Datalogy programs.

TL;DR: Si GP={P/P est une partition de V et chaque ensemble dans P domine V} alors le nombre domatique est le maximum des cardinaux de ces P, un donne un algorithme lineaire de calcul de ce nombres.

TL;DR: The current record bound on the number of processors required in O(log2n) step parallel arithmetic algorithms over rationals for the exact evaluation of the inverse and all coefficients of the characteristic polynomial of an n × n rational, real, or complex matrix A is decreased.

TL;DR: A set of experimental results show the exact run-time improvement due to both procedure integration and the use of interprocedural data-flow information, as well as the relative impact on compilation time and object code size.

TL;DR: The symmetric quotient of two relations as a new construct in abstract relational algebra generalizing the notion of a “noyau” of Riguet is introduced and a monomorphic characterization of powersets and function domains is given.

TL;DR: An algorithm that in m⩽n iterations obtains r 1 2 m ⩽d p ⩼ min { 3 r 1, 5−2 3 r m } for k fixed, where k fixed is O(n).

TL;DR: An Ω(n log n) fixed order algebraic decision tree lower bound for determining the existence of a line stabber for a family of n line segments in the plane is presented and it is shown that this problem is equivalent to determining if the width of a set of points is less than or equal to w.

TL;DR: A new tree transformation algorithm is presented, leading to an elementary proof of the bound 2 n −6, the minimum number of rotations needed to transform T 1 into T 2.

TL;DR: It is demonstrated that a certain class of naturally occuring problems involving an oracle are solvable in random polynomial time, but not in deterministic polynometric time.

TL;DR: A new pumping lemma and a new iteration theorem for deterministic context-free languages (DCFLs) are introduced and it is conjecture that there exist languages that can be shown not to be DCFLs by this new result but cannot be shown by the existing one.