Abstract
We study an optimal transport problem with a backward martingale constraint in a pseudo-Euclidean space S. We show that the dual problem consists in the minimization of the expected values of the Fitzpatrick functions associated with maximal S-monotone sets. An optimal plan γ and an optimal maximal S-monotone set G are characterized by the condition that the support of γ is contained in the graph of the S-projection on G. For a Gaussian random variable Y, we get a unique decomposition: , where X and Z are independent Gaussian random variables taking values, respectively, in complementary positive and negative linear subspaces of the S-space.
Funding Statement
The first author also has a research position at the University of Oxford. The second author was supported in part by the National Science Foundation under Grant DMS 1908903.
Acknowledgments
We thank Dejan Slepčev for pointing out the reference [10] and the related line of research. We also thank an anonymous referee for a careful reading and thoughtful suggestions.
Citation
Dmitry Kramkov. Mihai Sîrbu. "Backward martingale transport and Fitzpatrick functions in pseudo-Euclidean spaces." Ann. Appl. Probab. 34 (1B) 1571 - 1599, February 2024. https://doi.org/10.1214/23-AAP1998
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