Duality for Borel measurable cost functions
arXiv:0807.1468
Abstract
We consider the Monge-Kantorovich transport problem in an abstract measure theoretic setting. Our main result states that duality holds if is an arbitrary Borel measurable cost function on the product of Polish spaces . In the course of the proof we show how to relate a non - optimal transport plan to the optimal transport costs via a ``subsidy'' function and how to identify the dual optimizer. We also provide some examples showing the limitations of the duality relations.