This paper studies the classical tomographical problem of the reconstruction of a binary matrix from projections in presence of absorption. In particular, we consider two projections along the horizontal and vertical ...
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In this paper we show that every simple cubic graph on n vertices has a set of at least [n/4] disjoint 2-edge paths and that this bound is sharp. Our proof provides a polynomial time algorithm for finding such a set i...
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In this paper we show that every simple cubic graph on n vertices has a set of at least [n/4] disjoint 2-edge paths and that this bound is sharp. Our proof provides a polynomial time algorithm for finding such a set in a simple cubic graph. (C) 2003 Wiley Periodicals, Inc.
We investigate a curious problem from additive number theory: Given two positive integers S and Q, does there exist a sequence of positive integers that add up to S and whose squares add up to Q? We show that this pro...
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We investigate a curious problem from additive number theory: Given two positive integers S and Q, does there exist a sequence of positive integers that add up to S and whose squares add up to Q? We show that this problem can be solved in timepolynomially bounded in the logarithms of S and Q. As a consequence, also the following question can be answered in polynomialtime: For given numbers n and m, do there exist n lines in the Euclidean plane with exactly m points of intersection? (C) 2004 Published by Elsevier B.V.
We consider a hierarchical optimization problem for imprecise computation tasks, where each task is weighted with two weights, w and w'. The primary criterion is to minimize the total w-weighted error of all optio...
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We consider a hierarchical optimization problem for imprecise computation tasks, where each task is weighted with two weights, w and w'. The primary criterion is to minimize the total w-weighted error of all optional parts of tasks and the secondary criterion is to minimize the maximum w-weighted error. An algorithm is given with time complexity O(kn(3) log(2)n) for parallel and identical processors and O(kn(2)) for a single processor, where k is the number of distinct w-weights.
A recent paper [Eur. J. Operat. Res. 127 (2000) 120] addresses a flow-shop scheduling problem, where (i) each of the it jobs is limited to at most two operations, and (ii) one of these operations is common for all the...
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A recent paper [Eur. J. Operat. Res. 127 (2000) 120] addresses a flow-shop scheduling problem, where (i) each of the it jobs is limited to at most two operations, and (ii) one of these operations is common for all the jobs. The paper introduces a polynomialtime solution algorithm for the problem, which appears to be surprisingly simple. Our short note contains several comments related to the correctness of the algorithm, to its complexity, to the proof of optimality and to a possible extension. (C) 2003 Elsevier B.V. All rights reserved.
We study the multiobjective control of time-discrete systems with given starting and final states. The dynamics of the system is controled by p actors (players) which intend to minimize their integral-time costs of sy...
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n this paper, a polynomialalgorithm for a special case of knapsack sharingproblem is presented by decomposing it into a series of multidimentional knapsackproblems, without the assumption that the number of the const...
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n this paper, a polynomialalgorithm for a special case of knapsack sharingproblem is presented by decomposing it into a series of multidimentional knapsackproblems, without the assumption that the number of the constraints is a *** solve optimally this special version of the problem, which extends the presentwork.
The security of the RSA cryptosystems is based on the difficulty of factoring a large composite integer. In 1994, Shor showed that factoring a large composite is executable in polynomialtime if we use a quantum Turin...
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The security of the RSA cryptosystems is based on the difficulty of factoring a large composite integer. In 1994, Shor showed that factoring a large composite is executable in polynomialtime if we use a quantum Turing machine. Since this algorithm is complicated, straightforward implementations seem impractical judging from current technologies. In this paper, we propose simple and efficient algorithms for factoring and discrete logarithm problem based on NMR quantum computers. Our algorithms are easier to implement if we consider NMR quantum computers with small qubits.
We introduce a series of new polynomially computable implicit operations on the class of all finite semigroups. These new operations enable us to construct a finite pro-identity basis for the pseudovariety (H) over ba...
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We introduce a series of new polynomially computable implicit operations on the class of all finite semigroups. These new operations enable us to construct a finite pro-identity basis for the pseudovariety (H) over bar of all finite semigroups whose subgroups belong to a given finitely based pseudovariety H of finite groups.
A formula (in conjunctive normal form) is said to be minimal unsatisfiable if it is unsatisfiable and deleting any clause makes it satisfiable. The deficiency of a formula is the difference of the number of clauses an...
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A formula (in conjunctive normal form) is said to be minimal unsatisfiable if it is unsatisfiable and deleting any clause makes it satisfiable. The deficiency of a formula is the difference of the number of clauses and the number of variables. It is known that every minimal unsatisfiable formula has positive deficiency. Until recently, polynomial-timealgorithms were known to recognize minimal unsatisfiable formulas with deficiency 1 and 2. We state an algorithm which recognizes minimal unsatisfiable formulas with any fixed deficiency in polynomialtime. (C) 2002 Elsevier Science B.V. All rights reserved.
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