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An exact hierarchy for Lebesgue's universal covering constant and a certified 0.834 lower bound
Abstract
Posed by Lebesgue in 1914, the universal covering problem asks for the smallest-area planar convex set containing a congruent copy of every set of diameter at most one. We introduce an exact Reuleaux-type variational hierarchy for this constant: its monotone finite-arc values ΛM satisfy aLeb=limM→∞ΛM, and each level is a continuous finite-dimensional problem. We prove 0≤ aLeb−ΛM≤ C M−2, giving a controlled finite-arc route to the constant itself. As a certified low-order realization, an outward-rounded interval certificate for a regular finite Reuleaux subtest proves aLeb≥0.834, improving the lower-bound benchmark established by Brass and Sharifi in 2005.
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BibTeX
@misc{zeng2026exact,
title = {{An exact hierarchy for Lebesgue's universal covering constant and a certified 0.834 lower bound}},
author = {Shuai Zeng},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.01284},
eprint = {2609.01284},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.01284},
}
RIS
TY - UNPB
TI - An exact hierarchy for Lebesgue's universal covering constant and a certified 0.834 lower bound
AU - Shuai Zeng
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2609.01284
UR - https://arxiv.org/abs/2609.01284
AB - Posed by Lebesgue in 1914, the universal covering problem asks for the smallest-area planar convex set containing a congruent copy of every set of diameter at most one. We introduce an exact Reuleaux-type variational hierarchy for this constant: its monotone finite-arc values Λ_M satisfy a_Leb=lim_M→∞Λ_M, and each level is a continuous finite-dimensional problem. We prove 0≤ a_Leb−Λ_M≤ C M^−2, giving a controlled finite-arc route to the constant itself. As a certified low-order realization, an outward-rounded interval certificate for a regular finite Reuleaux subtest proves a_Leb≥0.834, improving the lower-bound benchmark established by Brass and Sharifi in 2005.
ER -