Perelman's entropy and Gromov-Hausdorff versus dynamical stability of round spheres
Abstract
We study the Gromov-Hausdorff stability of round spheres under perturbations of Perelman's nu-entropy. We show that in dimension two almost maximal entropy, together with an area normalisation, implies Gromov-Hausdorff closeness to the round two-sphere. In contrast, in dimensions at least three, we construct smooth metrics on the sphere whose entropies converge to that of the round sphere, but which remain a definite Gromov-Hausdorff distance away from it. These metrics can be chosen conformal and uniformly bi-Lipschitz equivalent to the round metric, with the same volume as the round sphere. Finally, in dimension three, we contrast this Gromov-Hausdorff instability with a dynamical stability result: metrics with nu-entropy above that of the round shrinking cylinder converge exponentially fast to round metrics under the volume-normalised Ricci flow.
Related
- Gromov-Hausdorff distance and stability of dynamical systems
- Gromov-Hausdorff Distances Between Spheres: Asymptotics and Vietoris-Rips Coindex Bounds
- Flexibility of topological entropy and factor persistence in the C0-Gromov Hausdorff topology
- The entropy production is not always monotone for hard spheres or for Maxwell molecules
- Maximum Entropy Probability Distributions on Spheres with Fixed Mean Busemann Function and Holomorphic-Information-Geometric Model of Cognition
BibTeX
@misc{buzano2026perelmans,
title = {{Perelman's entropy and Gromov-Hausdorff versus dynamical stability of round spheres}},
author = {Reto Buzano and Shengwen Wang},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.06678},
eprint = {2611.06678},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.06678},
}
RIS
TY - UNPB
TI - Perelman's entropy and Gromov-Hausdorff versus dynamical stability of round spheres
AU - Reto Buzano
AU - Shengwen Wang
PY - 2026
DA - 2026/11/04
PB - arXiv
DO - 10.48550/arxiv.2611.06678
UR - https://arxiv.org/abs/2611.06678
AB - We study the Gromov-Hausdorff stability of round spheres under perturbations of Perelman's nu-entropy. We show that in dimension two almost maximal entropy, together with an area normalisation, implies Gromov-Hausdorff closeness to the round two-sphere. In contrast, in dimensions at least three, we construct smooth metrics on the sphere whose entropies converge to that of the round sphere, but which remain a definite Gromov-Hausdorff distance away from it. These metrics can be chosen conformal and uniformly bi-Lipschitz equivalent to the round metric, with the same volume as the round sphere. Finally, in dimension three, we contrast this Gromov-Hausdorff instability with a dynamical stability result: metrics with nu-entropy above that of the round shrinking cylinder converge exponentially fast to round metrics under the volume-normalised Ricci flow.
ER -