Polyhedral results for some constrained arc-routing problems

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Lower Bounds for the Minimum Linear Arrangement of a Graph

Minimum Linear Arrangement is a classical basic combinatorial optimization problem from the 1960s, which turns out to be extremely challenging in practice. In particular, for most of its benchmark instances, even the order of magnitude of the optimal solution value is unknown, as testified by the surveys on the problem that contain tables in which the best known solution value often has one more digit than the best known lower bound value. In this paper, we propose a linear-programming based approach to compute lower bounds on the optimum. This allows us, for the first time, to show that the best known solutions are indeed not far from optimal for most of the benchmark instances

New techniques for cost sharing in combinatorial optimization games

Combinatorial optimization games form an important subclass of cooperative games. In recent years, increased attention has been given to the issue of finding good cost shares for such games. In this paper, we define a very general class of games, called integer minimization games, which includes the combinatorial optimization games in the literature as special cases. We then present new techniques, based on row and column generation, for computing good cost shares for these games. To illustrate the power of these techniques, we apply them to traveling salesman and vehicle routing games. Our results generalize and unify several results in the literature. The main underlying idea is that suitable valid inequalities for the associated combinatorial optimization problems can be used to derive improved cost shares

Manual de autoprotección escolar del I.E.S. Mare Nostrum (Alicante)

Bocanegra García, F. (2007). Manual de autoprotección escolar del I.E.S. Mare Nostrum (Alicante). http://hdl.handle.net/10251/32875.Archivo delegad

Worst-case analysis of maximal dual feasible functions

Dual feasible functions have been used to compute fast lower bounds and valid inequalities for integer linear problems. In this paper, we analyze the worst-case performance of the lower bounds provided by some of the best functions proposed in the literature. We describe some worst-case examples for these functions, and we report on new results concerning the best parameter choice for one of these functions