English

On Strassen's Theorem for support functions

Probability 2025-06-04 v2

Abstract

Strassen established that there exists a two step martingale with marginal distributions μ\mu, ν\nu if and only if μ\mu, ν\nu are in convex order. Recently Chon\'e-Gozlan-Kramarz obtained a transport characterization of the stochastic order defined by convex positively 1-homogeneous functions, in the spirit of Strassen's theorem under certain technical assumptions. In this note we prove the Chon\'e-Gozlan-Kramarz result in full generality. We also observe that the restriction of the result to the case where μ,ν\mu, \nu are supported on a half space is equivalent to Strassen's classical theorem.

Keywords

Cite

@article{arxiv.2310.20402,
  title  = {On Strassen's Theorem for support functions},
  author = {Stefan Schrott and Daniel Toneian},
  journal= {arXiv preprint arXiv:2310.20402},
  year   = {2025}
}
R2 v1 2026-06-28T13:07:19.744Z