Finding extremal graphs for expressions involving one or more invariants is viewed as a problem of combinatorial optimization. The recent Variable Neighborh...

We study the set of lower bounds which have been proposed for the numbering of a complete graph. We first show that the computation of most of them can be ...

Good heuristic solutions for large Multisource Weber problems can be obtained by solving related <i>p</i>-median problems in which potential locations of th...

Systematic change of neighborhood within a local search algorithm yields a simple and effective metaheuristic for combinatorial optimization. We present a ...

The multisource Weber problem is to locate simultaneously <i>m</i> facilities in the Euclidean plane in order to minimize the total transportation cost for ...

A hypergraph <i>H=(X,E)</i> is <i>nested</i> if its edges are pairwise disjoint or included one into the other. The <i>nesticity</i> of <i>H</i> is defined...

Given a set of entities, Cluster Analysis aims at finding subsets, called clusters, which are homogeneous and/or well separated. As many types of clusterin...

La méthode de génération de colonnes est couramment utilisée pour résoudre des problèmes d'optimisation de grande taille. En pratique, on observe fréquemmen...

We study both the continuous and discrete problems of maximizing the product of two linear functions subject to all variables being between 0 and~1. We fir...

It is shown that the anytime deduction procedure for probabilistic entailment of Frisch and Haddawy does not have the correctness property when the probabil...

Clustering with a criterion which minimizes the sum of squared distances to cluster centroids is usually done in a heuristic way. An exact polynomial algori...

Two new path problems in graphs are studied: MINRANGE, i.e., find a path from a vertex <i>s</i> to a vertex <i>t</i> with the smallest possible range of a...

Two new algorithms are proposed for the problem of positioning a new product in attribute space in order to attract the maximum number of consumers. Each c...

A review is made of models and algorithms for probabilistic satisfiability and its extensions. The basic probabilistic satisfiability problem, in decision f...

Extension of input-output functions for generating units allows simultaneous solution of the static unit commitment and economic dispatch problems by dynami...

Zone pricing consists in determining simultaneously several delivered prices together with the zones where they are applied. A model and algorithm are prop...

The column generation approach to large-scale linear programming is extended to the mixed-integer case. Two general algorithms, a dual and a primal one, are...

We give lower and upper bounds for the number of reducible ears as well as upper bounds for the number of perfect matchings in an elementary bipartite graph...

The maxmin problem models a game sequentially played by two players having opposite objective. Before making his move, the first player must anticipate the...

A mixed graph <i>G_{<img src="theta.gif">}</i> contains both undirected edges and directed arcs. A <i>k</i>-coloring of <i>G<sub><img src="theta.g...