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DAM
2006
136views more  DAM 2006»
13 years 4 months ago
The complexity of maximum matroid-greedoid intersection and weighted greedoid maximization,
The maximum intersection problem for a matroid and a greedoid, given by polynomialtime oracles, is shown NP-hard by expressing the satisfiability of boolean formulas in 3-conjunct...
Taneli Mielikäinen, Esko Ukkonen
DAM
2006
78views more  DAM 2006»
13 years 4 months ago
Hybrid rounding techniques for knapsack problems
We address the classical knapsack problem and a variant in which an upper bound is imposed on the number of items that can be selected. We show that appropriate combinations of ro...
Monaldo Mastrolilli, Marcus Hutter
DAM
2006
172views more  DAM 2006»
13 years 4 months ago
A Branch-and-Cut algorithm for graph coloring
In a previous work, we proposed a new integer programming formulation for the graph coloring problem which, to a certain extent, avoids symmetry. We studied the facet structure of...
Isabel Méndez-Díaz, Paula Zabala
DAM
2006
47views more  DAM 2006»
13 years 4 months ago
Trees of extremal connectivity index
The connectivity index w(G) of a graph G is the sum of the weights (d(u)d(v)) of all edges uv of G, where is a real number ( = 0), and d(u) denotes the degree of the vertex u. Le...
Huiqing Liu, Mei Lu, Feng Tian
DAM
2006
93views more  DAM 2006»
13 years 4 months ago
Update schedules of sequential dynamical systems
Sequential dynamical systems have the property, that the updates of states of individual cells occur sequentially, so that the global update of the system depends on the order of t...
Reinhard Laubenbacher, Bodo Pareigis
DAM
2006
57views more  DAM 2006»
13 years 4 months ago
The Hamiltonian problem on distance-hereditary graphs
Sun-Yuan Hsieh, Chin-Wen Ho, Tsan-sheng Hsu, Ming-...
DAM
2006
81views more  DAM 2006»
13 years 4 months ago
Equivalence-free exhaustive generation of matroid representations
Abstract. In this paper we present an algorithm for the problem of exhaustive equivalence-free generation of 3-connected matroids which are represented by a matrix over some finite...
Petr Hlinený
DAM
2006
89views more  DAM 2006»
13 years 4 months ago
First vs. best improvement: An empirical study
When applying the 2-opt heuristic to the travelling salesman problem, selecting the best improvement at each iteration gives worse results on average than selecting the first impr...
Pierre Hansen, Nenad Mladenovic
DAM
2006
66views more  DAM 2006»
13 years 4 months ago
Positivity of second order linear recurrent sequences
We give an elementary proof for the Positivity Problem for second order recurrent sequences: it is decidable whether or not a recurrent sequence defined by un = aun-1 + bun-2 has ...
Vesa Halava, Tero Harju, Mika Hirvensalo