Multicriteria network location problems with sum objectives

In this paper, network location problems with several objectives are discus sed, where every single objective is a classical median objective function. We will look at the problem of finding Pareto optimal locations and lexico graphically optimal locations. It is shown that for Pareto optimal location s in undirected networks no node dominance result can be shown. Structural results as well as efficient algorithms for these multicriteria problems ar e developed. In the special case of a tree network, a generalization of Gol dman's dominance algorithm for finding Pareto locations is presented. (C) 1 999 John Wiley & Sons, Inc.