On the rigidity of Wasserstein contraction along heat flows

Fuente: arXiv
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Main Author: Li, Zhenhao
Format: Preprint
Published: 2025
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author Li, Zhenhao
author_facet Li, Zhenhao
contents We establish an equivalence between the rigidity of Wasserstein contraction along heat flows and the rigidity of Bakry--Émery gradient estimates for Lipschitz functions. Applying results of Ambrosio--Brué--Semola and Han, we show that if an $\rcd$ space with Ricci lower bound $K\in[0,\infty)$ admits two distinct points $x,y$ such that the $2$-Wasserstein distance between the associated heat kernels satisfies \[ W_2(p_t(x,\cdot), p_t(y,\cdot)) = e^{-Kt} d(x,y), \] then the space splits off a line. Moreover, for weighted smooth manifolds, we provide a direct proof of the rigidity theorem for all curvature bounds $K \in \mathbb{R}$. In particular, we characterize a class of weighted Euclidean spaces as the only spaces where the Wasserstein contraction is sharp for all pairs of points.
format Preprint
id arxiv_https___arxiv_org_abs_2505_02280
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the rigidity of Wasserstein contraction along heat flows
Li, Zhenhao
Metric Geometry
Differential Geometry
53C23, 49Q22, 53C24
We establish an equivalence between the rigidity of Wasserstein contraction along heat flows and the rigidity of Bakry--Émery gradient estimates for Lipschitz functions. Applying results of Ambrosio--Brué--Semola and Han, we show that if an $\rcd$ space with Ricci lower bound $K\in[0,\infty)$ admits two distinct points $x,y$ such that the $2$-Wasserstein distance between the associated heat kernels satisfies \[ W_2(p_t(x,\cdot), p_t(y,\cdot)) = e^{-Kt} d(x,y), \] then the space splits off a line. Moreover, for weighted smooth manifolds, we provide a direct proof of the rigidity theorem for all curvature bounds $K \in \mathbb{R}$. In particular, we characterize a class of weighted Euclidean spaces as the only spaces where the Wasserstein contraction is sharp for all pairs of points.
title On the rigidity of Wasserstein contraction along heat flows
topic Metric Geometry
Differential Geometry
53C23, 49Q22, 53C24
url https://arxiv.org/abs/2505.02280