Proof of the local version of the Pólya--Szegö conjecture for the torsional rigidity of polygons
Abstract
We prove the local version of the Pólya--Szegö conjecture for the torsional rigidity of polygons: for every n≥5, the regular n-gon is a strict local maximizer of torsional rigidity among convex n-gons of prescribed area. Our proof is entirely analytic. It builds on a locally stable proportional triangular covering inspired by Solynin and Zalgaller and an associated weighted Voronoi-type partition, together with a quantitative asymptotic analysis of the loss produced by truncating the overlapping triangles to the partition cells. The result is then obtained by establishing two key ingredients: the optimality of isosceles triangles for mixed torsional rigidity at fixed area and vertex angle, and a strict concavity property of the mixed torsional rigidity of isosceles triangles.
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BibTeX
@misc{bogosel2026proof,
title = {{Proof of the local version of the Pólya--Szegö conjecture for the torsional rigidity of polygons}},
author = {Beniamin Bogosel and Dorin Bucur and Ilaria Fragalà},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.23051},
eprint = {2609.23051},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.23051},
}
RIS
TY - UNPB
TI - Proof of the local version of the Pólya--Szegö conjecture for the torsional rigidity of polygons
AU - Beniamin Bogosel
AU - Dorin Bucur
AU - Ilaria Fragalà
PY - 2026
DA - 2026/09/19
PB - arXiv
DO - 10.48550/arxiv.2609.23051
UR - https://arxiv.org/abs/2609.23051
AB - We prove the local version of the Pólya--Szegö conjecture for the torsional rigidity of polygons: for every n≥5, the regular n-gon is a strict local maximizer of torsional rigidity among convex n-gons of prescribed area. Our proof is entirely analytic. It builds on a locally stable proportional triangular covering inspired by Solynin and Zalgaller and an associated weighted Voronoi-type partition, together with a quantitative asymptotic analysis of the loss produced by truncating the overlapping triangles to the partition cells. The result is then obtained by establishing two key ingredients: the optimality of isosceles triangles for mixed torsional rigidity at fixed area and vertex angle, and a strict concavity property of the mixed torsional rigidity of isosceles triangles.
ER -