The biobjective inventory routing problem – problem solution and decision support Martin Josef Geiger and Marc Sevaux Abstract The article presents a study on a biobjective generalization of the inventory routing problem, an important optimization problem found in logistical networks in which aspects of inventory management and vehicle routing intersect. A compact solution representation and a heuristic optimization approach are presented, and experimental investigations involving novel benchmark instances are carried out. As the investigated problem is computationally very demanding, only a small subset of solutions can be computed within reasonable time. Decision support is nevertheless obtained by means of a set of reference points, which guide the search towards the Pareto-front. Keywords: Inventory routing, computational logistics, multi-objective optimiza- tion, heuristic approaches, decision support system. 1 Introduction Many logistical activities are commonly concerned with moving required items through a graph, often referred to as a “supply chain” or “supply network”. Natu- rally, numerous aspects influence the way in which such processes are organized, in- cluding macro- and microeconomical conditions, the objectives of the players along the supply chain, their interrelations, and their technical abilities of communicating and thus exchanging the required information. Consequently, different implementa- M.J. Geiger Helmut Schmidt University – Logistics Management Department – Hamburg, Germany. e-mail: m.j.geiger@hsu-hh.de M. Sevaux Helmut Schmidt University – Logistics Management Department – Hamburg, Germany. Universit´ e de Bretagne-Sud – Lab-STICC, Lorient, France. e-mail: marc.sevaux@ univ-ubs.fr 1