English

Reverse Loomis-Whitney inequalities via isotropicity

Metric Geometry 2020-02-03 v1 Functional Analysis

Abstract

Given a centered convex body KRnK\subseteq\mathbb{R}^n, we study the optimal value of the constant Λ~(K)\tilde{\Lambda}(K) such that there exists an orthonormal basis {wi}i=1n\{w_i\}_{i=1}^n for which the following reverse dual Loomis-Whitney inequality holds: Kn1Λ~(K)i=1nKwi. |K|^{n-1}\leqslant \tilde{\Lambda}(K)\prod_{i=1}^n|K\cap w_i^\perp|. We prove that Λ~(K)(CLK)n\tilde{\Lambda}(K)\leqslant(CL_K)^n for some absolute C>1C>1 and that this estimate in terms of LKL_K, the isotropic constant of KK, is asymptotically sharp in the sense that there exists another absolute constant c>1c>1 and a convex body KK such that (cLK)nΛ~(K)(CLK)n(cL_K)^n\leqslant\tilde{\Lambda}(K)\leqslant(CL_K)^n. We also prove more general reverse dual Loomis-Whitney inequalities as well as reverse restricted versions of Loomis-Whitney and dual Loomis-Whitney inequalities.

Keywords

Cite

@article{arxiv.2001.11876,
  title  = {Reverse Loomis-Whitney inequalities via isotropicity},
  author = {David Alonso-Gutiérrez and Silouanos Brazitikos},
  journal= {arXiv preprint arXiv:2001.11876},
  year   = {2020}
}
R2 v1 2026-06-23T13:26:40.440Z