Stronger multi-commodity flow formulations of the (capacitated) sequential ordering problem

Letchford, Adam and Salazar Gonzalez, Juan Jose (2016) Stronger multi-commodity flow formulations of the (capacitated) sequential ordering problem. European Journal of Operational Research, 251 (1). pp. 74-84. ISSN 0377-2217

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The sequential ordering problem (SOP) is the generalisation of the asymmetric travelling salesman problem in which there are precedence relations between pairs of nodes. Hernandez & Salazar introduced a multi-commodity flow (MCF) formulation for a generalisation of the SOP in which the vehicle has a limited capacity. We strengthen this MCF formulation by fixing variables and adding valid equations. We then use polyhedral projection, together with some known results on flows, cuts and metrics, to derive new families of strong valid inequalities for both problems. Finally, we give computational results, which show that our findings yield good lower bounds in practice.

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Journal Article
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European Journal of Operational Research
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This is the author’s version of a work that was accepted for publication in European Journal of Operational Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in European Journal of Operational Research, 251, 1, 2015 DOI: 10.1016/j.ejor.2015.11.001
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Deposited On:
02 Nov 2015 14:36
Last Modified:
22 Nov 2022 02:30