The isometry group of Wasserstein spaces: the Hilbertian case

Fuente: arXiv
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Autores principales: Gehér, György Pál, Titkos, Tamás, Virosztek, Dániel
Formato: Preprint
Publicado: 2021
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author Gehér, György Pál
Titkos, Tamás
Virosztek, Dániel
author_facet Gehér, György Pál
Titkos, Tamás
Virosztek, Dániel
contents Motivated by Kloeckner's result on the isometry group of the quadratic Wasserstein space $\mathcal{W}_2\left(\mathbb{R}^n\right)$, we describe the isometry group $\mathrm{Isom}\left(\mathcal{W}_p (E)\right)$ for all parameters $0 < p < \infty$ and for all separable real Hilbert spaces $E.$ In particular, we show that $\mathcal{W}_p(X)$ is isometrically rigid for all Polish space $X$ whenever $0<p<1$. This is a consequence of our more general result: we prove that $\mathcal{W}_1(X)$ is isometrically rigid if $X$ is a complete separable metric space that satisfies the strict triangle inequality. Furthermore, we show that this latter rigidity result does not generalise to parameters $p>1$, by solving Kloeckner's problem affirmatively on the existence of mass-splitting isometries.
format Preprint
id arxiv_https___arxiv_org_abs_2102_02037
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle The isometry group of Wasserstein spaces: the Hilbertian case
Gehér, György Pál
Titkos, Tamás
Virosztek, Dániel
Metric Geometry
Mathematical Physics
Functional Analysis
Probability
Primary: 54E40, 46E27, Secondary: 60A10, 60B05
Motivated by Kloeckner's result on the isometry group of the quadratic Wasserstein space $\mathcal{W}_2\left(\mathbb{R}^n\right)$, we describe the isometry group $\mathrm{Isom}\left(\mathcal{W}_p (E)\right)$ for all parameters $0 < p < \infty$ and for all separable real Hilbert spaces $E.$ In particular, we show that $\mathcal{W}_p(X)$ is isometrically rigid for all Polish space $X$ whenever $0<p<1$. This is a consequence of our more general result: we prove that $\mathcal{W}_1(X)$ is isometrically rigid if $X$ is a complete separable metric space that satisfies the strict triangle inequality. Furthermore, we show that this latter rigidity result does not generalise to parameters $p>1$, by solving Kloeckner's problem affirmatively on the existence of mass-splitting isometries.
title The isometry group of Wasserstein spaces: the Hilbertian case
topic Metric Geometry
Mathematical Physics
Functional Analysis
Probability
Primary: 54E40, 46E27, Secondary: 60A10, 60B05
url https://arxiv.org/abs/2102.02037