Improved fixed point optimality conditions for mixed norms minisum location

We improve and extend sufficient conditions for an optimal solution to happen at a fixed point in a single facility minisum location model with mixed transportation modes recently proposed and studied by Brimberg, Love and Mladenović. In particular, conditions are derived that are valid for general mixed metrics, while for mixed ℓ <Subscript> p </Subscript>-norms, possibly with rotated axes, much stronger conditions are obtained. An example demonstrates the superiority of the new conditions. Copyright Sociedad de Estadística e Investigación Operativa 2014