The Pólya--Szegő conjecture for convex polygons with many sides
Abstract
For every sufficiently large N, we prove that the regular N-gon uniquely minimizes the first Dirichlet eigenvalue among convex polygons of prescribed area with at most N sides, up to rigid motions. Quantitative Faber--Krahn stability localizes minimizers near the disk but leaves their discrete geometry undetermined. We encode that geometry by a centered measure of exterior angles and prove an inverse-cubic Fourier inequality whose equality case is the uniform root configuration. Its defect gives a lower bound for the quadratic spectral excess over the regular polygon. Cyclic cancellation and a common material-coordinate comparison make the nonlinear difference small relative to the same defect. Exact constraint coordinates extend this comparison to arbitrarily small positive defects. Minimality then forces zero defect, which characterizes the regular polygon.
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BibTeX
@misc{cheng2026pólyaszegő,
title = {{The Pólya--Szegő conjecture for convex polygons with many sides}},
author = {Zhuo Cheng and Changfeng Gui and Yeyao Hu and Qinfeng Li},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.18500},
eprint = {2609.18500},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.18500},
}
RIS
TY - UNPB
TI - The Pólya--Szegő conjecture for convex polygons with many sides
AU - Zhuo Cheng
AU - Changfeng Gui
AU - Yeyao Hu
AU - Qinfeng Li
PY - 2026
DA - 2026/09/16
PB - arXiv
DO - 10.48550/arxiv.2609.18500
UR - https://arxiv.org/abs/2609.18500
AB - For every sufficiently large N, we prove that the regular N-gon uniquely minimizes the first Dirichlet eigenvalue among convex polygons of prescribed area with at most N sides, up to rigid motions. Quantitative Faber--Krahn stability localizes minimizers near the disk but leaves their discrete geometry undetermined. We encode that geometry by a centered measure of exterior angles and prove an inverse-cubic Fourier inequality whose equality case is the uniform root configuration. Its defect gives a lower bound for the quadratic spectral excess over the regular polygon. Cyclic cancellation and a common material-coordinate comparison make the nonlinear difference small relative to the same defect. Exact constraint coordinates extend this comparison to arbitrarily small positive defects. Minimality then forces zero defect, which characterizes the regular polygon.
ER -