Characterizing generalized trade-off directions

Recently, so-called trade-off directions have been introduced for convex multiobjective optimization problems and, later, they have been generalized for convex problems. The trade-off directions are characterized with the help of tangent and contingent cones. Trade-offs give information about the interrelations of the changes in the objective function values in different Pareto optimal solutions. Such information is valuable when searching for the most preferable Pareto optimal solution. Here, we introduce characterizations of generalised trade-off directions using the tools of nonsmooth analysis. In this way, it is possible to analytically describe concepts that originally were geometrical.