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A covering problem posed by Henri Lebesgue in 1914 seeks to find the convex shape of smallest area that contains a subset congruent to any point set of unit diameter in the Euclidean plane. Methods used previously to construct such a…

Metric Geometry · Mathematics 2018-10-25 Philip Gibbs

In 1914 Lebesgue defined a "universal covering" to be a convex subset of the plane that contains an isometric copy of any subset of diameter 1. His challenge of finding a universal covering with the least possible area has been addressed by…

Metric Geometry · Mathematics 2017-08-22 John C. Baez , Karine Bagdasaryan , Philip Gibbs

In this paper, we provide a lower bound for an area of the convex hull of points and a rectangle in a plane. We then apply this estimate to establish a lower bound for a universal cover problem. We showed that a convex universal cover for a…

Metric Geometry · Mathematics 2015-03-18 Tirasan Khandhawit , Dimitrios Pagonakis , Sira Sriswasdi

We improve a lower bound for the smallest area of convex covers for closed unit curves from 0.0975 to 0.1, which makes it substantially closer to the current best upper bound 0.11023. We did this by considering the minimal area of convex…

Metric Geometry · Mathematics 2020-04-08 Bogdan Grechuk , Sittichoke Som-am

We combine geometric methods with numerical box search algorithm to show that the minimal area of a convex set on the plane which can cover every closed plane curve of unit length is at least 0.0975. This improves the best previous lower…

Metric Geometry · Mathematics 2019-05-02 Bogdan Grechuk , Sittichoke Som-Am

Universal cover in $\mathbb{E}^{n}$ is a measurable set that contains a congruent copy of any set of diameter 1. Lebesgue's universal covering problem, posed in 1914, asks for the convex set of smallest area that serves as a universal cover…

Metric Geometry · Mathematics 2025-12-04 Andrii Arman , Andriy Bondarenko , Andriy Prymak , Danylo Radchenko

In this paper, we consider the problem of covering a plane region with unit discs. We present an improved upper bound and the first nontrivial lower bound on the number of discs needed for such a covering, depending on the area and…

Computational Geometry · Computer Science 2021-08-03 Shai Gul , Reuven Cohen , Simi Haber

We give two new upper bounds on the covering minima of convex bodies, depending on covering minima of certain projections and intersections with linear subspaces. We show one bound to be sharp for direct sums of two convex bodies,…

Combinatorics · Mathematics 2026-05-12 Katarina Krivokuća

We consider the smallest-area universal covering of planar objects of perimeter 2 (or equivalently closed curves of length 2) allowing translation and discrete rotations. In particular, we show that the solution is an equilateral triangle…

Computational Geometry · Computer Science 2022-11-29 Mook Kwon Jung , Sang Duk Yoon , Hee-Kap Ahn , Takeshi Tokuyama

The Blaschke-Lebesgue Theorem states that among all planar convex domains of given constant width B the Reuleaux triangle has minimal area. It is the purpose of the present note to give a direct proof of this theorem by analyzing the…

Metric Geometry · Mathematics 2007-05-23 Evans M. Harrell

We raise and investigate the following problem that one can regard as a very close relative of the densest sphere packing problem. If the Euclidean 3-space is partitioned into convex cells each containing a unit ball, how should the shapes…

Metric Geometry · Mathematics 2013-02-13 Karoly Bezdek

We give a review of results on the minimum convex cover and maximum hidden set problems. In addition, we give some new results. First we show that it is NP-hard to determine whether a polygon has the same convex cover number as its hidden…

Computational Geometry · Computer Science 2026-04-30 Reilly Browne

We prove bounds for the covering numbers of classes of convex functions and convex sets in Euclidean space. Previous results require the underlying convex functions or sets to be uniformly bounded. We relax this assumption and replace it…

Information Theory · Computer Science 2014-10-24 Adityanand Guntuboyina

We give a universal upper bound for the total curvature of minimizing geodesic on a convex surface in the Euclidean space.

Differential Geometry · Mathematics 2019-01-08 Nina Lebedeva , Anton Petrunin

We obtain new upper bounds on the minimal density of lattice coverings of Euclidean space by dilates of a convex body K. We also obtain bounds on the probability (with respect to the natural Haar-Siegel measure on the space of lattices)…

Number Theory · Mathematics 2020-06-03 Or Ordentlich , Oded Regev , Barak Weiss

The Honeycomb Conjecture states that among tilings with unit area cells in the Euclidean plane, the average perimeter of a cell is minimal for a regular hexagonal tiling. This conjecture was proved by L. Fejes T\'oth for convex tilings, and…

Metric Geometry · Mathematics 2025-12-15 Zsolt Lángi , Shanshan Wang

We show that any convex region which contains a unit segment, an equilateral triangle of sides 1/2, and a square of side 1/3 always has area at least 0.227498. Using grid-search algorithm, we attempt to find a configuration of these three…

Metric Geometry · Mathematics 2009-06-05 Tirasan Khandhawit , Sira Sriswasdi

We present a method to obtain upper bounds on covering numbers. As applications of this method, we reprove and generalize results of Rogers on economically covering Euclidean $n$-space with translates of a convex body, or more generally,…

Metric Geometry · Mathematics 2015-10-12 Márton Naszódi

Let $H_n$ be the minimal number such that any $n$-dimensional convex body can be covered by $H_n$ translates of interior of that body. Similarly $H_n^s$ is the corresponding quantity for symmetric bodies. It is possible to define $H_n$ and…

Metric Geometry · Mathematics 2024-04-02 Andrii Arman , Andriy Bondarenko , Andriy Prymak

A central problem in discrete geometry, known as Hadwiger's covering problem, asks what the smallest natural number $N\left(n\right)$ is such that every convex body in ${\mathbb R}^{n}$ can be covered by a union of the interiors of at most…

Metric Geometry · Mathematics 2022-07-12 Han Huang , Boaz A. Slomka , Tomasz Tkocz , Beatrice-Helen Vritsiou
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