The stability of Sharp Poincaré and Brascamp--Lieb inequalities with full monomial weights
Abstract
It was known that the Gaussian measures with monomial weights satisfy the sharp pointwise curvature-dimension condition CD(1, ∞), and consequently they allow us to derive the sharp constant $1$ for the Poincaré inequality only with partial monomial weights. In this paper, we first establish the Gaussian measures with full monomial weights satisfy the integrated curvature-dimension condition ICD(2, ∞) which is sufficient for us to prove the sharp Poincaré inequalities with optimal constant $2$ and the stability of the Brascamp--Lieb inequality for full monomial Gaussian measures. Several of these results are extended to homogeneous Gaussian measures on convex cones. Using the sharp Poincaré inequality and the hypercontractivity, we obtain an improved Beckner inequality that recover the sharp Poincaré and logarithmic Sobolev constants at the endpoints. By developing a Laguerre spectral decomposition of the associated Ornstein--Uhlenbeck type generator, we derive an exact identity for the Poincaré deficit and obtain sharp gradient stability for the Poincaré inequality with full monomial weights. We further establish L2 and weighted gradient stability estimates for the Brascamp--Lieb inequality with explicit constants when all monomial exponents exceed $1$. The L2 estimate extends to log-concave homogeneous weights under a subharmonicity assumption. Finally, we obtain an improved integrated curvature-dimension bound under a scale-invariant Hessian condition and identify the sharp constant for the Poincaré inequality in the radial class.
Related
- Caffarelli-Kohn-Nirenberg and Weighted Gaussian Poincaré Inequalities: a complete characterization of sharp L2 stability and Lp extensions
- Sharp Stability of Brenier Potentials and its Link to Poincaré Inequalities
- Sharp L2-stability and gradient stability hierarchies of the L2-Poincaré inequalities on Euclidean balls and Gaussian Poincaré inequality
- A centroaffine perspective on improved Brascamp--Lieb and dimensional Brunn--Minkowski inequalities
- Ubiquity in the setting of forward-reverse Brascamp-Lieb inequalities
BibTeX
@misc{lam2026stability,
title = {{The stability of Sharp Poincaré and Brascamp--Lieb inequalities with full monomial weights}},
author = {Nguyen Lam and Guozhen Lu and Andrey Russanov},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.10337},
eprint = {2610.10337},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.10337},
}
RIS
TY - UNPB
TI - The stability of Sharp Poincaré and Brascamp--Lieb inequalities with full monomial weights
AU - Nguyen Lam
AU - Guozhen Lu
AU - Andrey Russanov
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2610.10337
UR - https://arxiv.org/abs/2610.10337
AB - It was known that the Gaussian measures with monomial weights satisfy the sharp pointwise curvature-dimension condition CD(1, ∞), and consequently they allow us to derive the sharp constant $1$ for the Poincaré inequality only with partial monomial weights. In this paper, we first establish the Gaussian measures with full monomial weights satisfy the integrated curvature-dimension condition ICD(2, ∞) which is sufficient for us to prove the sharp Poincaré inequalities with optimal constant $2$ and the stability of the Brascamp--Lieb inequality for full monomial Gaussian measures. Several of these results are extended to homogeneous Gaussian measures on convex cones. Using the sharp Poincaré inequality and the hypercontractivity, we obtain an improved Beckner inequality that recover the sharp Poincaré and logarithmic Sobolev constants at the endpoints. By developing a Laguerre spectral decomposition of the associated Ornstein--Uhlenbeck type generator, we derive an exact identity for the Poincaré deficit and obtain sharp gradient stability for the Poincaré inequality with full monomial weights. We further establish L^2 and weighted gradient stability estimates for the Brascamp--Lieb inequality with explicit constants when all monomial exponents exceed $1$. The L^2 estimate extends to log-concave homogeneous weights under a subharmonicity assumption. Finally, we obtain an improved integrated curvature-dimension bound under a scale-invariant Hessian condition and identify the sharp constant for the Poincaré inequality in the radial class.
ER -