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If E is any ellipse inscribed in a convex quadrilateral, D, then we prove that Area(E)/Area(D) is less than or equal to pi/4, and equality holds if and only if D is a parallelogram and E is tangent to the sides of D at the midpoints. This…

Classical Analysis and ODEs · Mathematics 2011-07-29 Alan Horwitz

We consider triangle faced convex polyhedra inscribed in the unit sphere $S^2$ in ${\Bbb{R}}^3$. One way of measuring their deviation from regular polyhedra with triangular faces is to consider the quotient of the lengths of the longest and…

Metric Geometry · Mathematics 2019-09-09 E. Makai,

A convex quadrilateral, $Q$, is called a midpoint diagonal quadrilateral if the intersection point of the diagonals of $Q$ coincides with the midpoint of at least one of the diagonals of $Q$. A parallelogram, P, is a special case of a…

Metric Geometry · Mathematics 2021-02-24 Alan Horwitz

We investigate the problem of partitioning a rectilinear polygon $P$ with $n$ vertices and no holes % with no holes into rectangles using disjoint line segments drawn inside $P$ under two optimality criteria. In the minimum ink partition,…

Computational Geometry · Computer Science 2021-11-04 Hwi Kim , Jaegun Lee , Hee-Kap Ahn

A convex partition of a point set P in the plane is a planar partition of the convex hull of P with empty convex polygons or internal faces whose extreme points belong to P. In a convex partition, the union of the internal faces give the…

Computational Geometry · Computer Science 2020-12-16 Hadrien Cambazard , Nicolas Catusse

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

We show that every (possibly unbounded) convex polygon $P$ in $R^2$ with $m$ edges can be represented by inequalities $p_1 \ge 0,...,p_n \ge 0,$ where the $p_i$'s are products of at most $k$ affine functions each vanishing on an edge of $P$…

Metric Geometry · Mathematics 2010-02-05 Gennadiy Averkov , Christian Bey

A well-known result by Kant [Algorithmica, 1996] implies that n-vertex outerplane graphs admit embedding-preserving planar straight-line grid drawings where the internal faces are convex polygons in $O(n^2)$ area. In this paper, we present…

Computational Geometry · Computer Science 2025-08-28 Michael A. Bekos , Giordano Da Lozzo , Fabrizio Frati , Giuseppe Liotta , Antonios Symvonis

We describe a polynomial time algorithm that takes as input a polygon with axis-parallel sides but irrational vertex coordinates, and outputs a set of as few rectangles as possible into which it can be dissected by axis-parallel cuts and…

Computational Geometry · Computer Science 2025-01-08 David Eppstein

We study the problem of computing a convex region with bounded area and diameter that contains the maximum number of points from a given point set $P$. We show that this problem can be solved in $O(n^6k)$ time and $O(n^3k)$ space, where $n$…

Computational Geometry · Computer Science 2025-07-08 Gianmarco Picarella , Marc van Kreveld , Frank Staals , Sjoerd de Vries

Consider the problem of fnding the smallest area convex $k$-gon containing $n\in\mathbb{N}$ congruent disks without an overlap. By using Wegner inequality in sphere packing theory we give a lower bound for the area of such polygons. For…

Optimization and Control · Mathematics 2021-02-05 Orgil-Erdene Erdenebaatar , Uuganbaatar Ninjbat

Let $n$ be a positive integer, not a power of two. A \textit{Reinhardt polygon} is a convex $n$-gon that is optimal in three different geometric optimization problems: it has maximal perimeter relative to its diameter, maximal width…

Metric Geometry · Mathematics 2012-09-28 Kevin G. Hare , Michael J. Mossinghoff

We prove the theorem mentioned in the title, for ${\mathbb{R}}^n$, where $n \ge 3$. The case of the simplex was known previously. Also, the case $n=2$ was settled, but there the infimum was some well-defined function of the side lengths. We…

Differential Geometry · Mathematics 2017-07-28 N. V. Abrosimov , E. Makai, , A. D. Mednykh , Yu. G. Nikonorov , G. Rote

Convex polytopes are convex hulls of point sets in the $n$-dimensional space $\E^n$ that generalize 2-dimensional convex polygons and 3-dimensional convex polyhedra. We concentrate on the class of $n$-dimensional polytopes in $\E^n$ called…

Quantum Physics · Physics 2010-12-15 Colin Wilmott , Hermann Kampermann , Dagmar Bruss

Polygons are described as almost-convex if their perimeter differs from the perimeter of their minimum bounding rectangle by twice their `concavity index', $m$. Such polygons are called \emph{$m$-convex} polygons and are characterised by…

Combinatorics · Mathematics 2007-10-26 W. R. G. James , I. Jensen , A. J. Guttmann

Given a convex polyhedron $P$ of $n$ vertices inside a sphere $Q$, we give an $O(n^3)$-time algorithm that cuts $P$ out of $Q$ by using guillotine cuts and has cutting cost $O((\log n)^2)$ times the optimal.

Computational Geometry · Computer Science 2010-03-10 Syed Ishtiaque Ahmed , Masud Hasan , Md. Ariful Islam

We study the problem of minimum enclosing rectangle with outliers, which asks to find, for a given set of $n$ planar points, a rectangle with minimum area that encloses at least $(n-t)$ points. The uncovered points are regarded as outliers.…

Computational Geometry · Computer Science 2021-09-16 Zhengyang Guo , Yi Li

In the paper we prove that the number of graphs inscribed into graph of a convex polyhedron and circumscribed around another graph does not exceed 4. For this we first studied Poncelet type problem about the number of convex $n$-gons…

General Mathematics · Mathematics 2025-09-22 Yagub N. Aliyev

We give an overview of the 2024 Computational Geometry Challenge targeting the problem \textsc{Maximum Polygon Packing}: Given a convex region $P$ in the plane, and a collection of simple polygons $Q_1, \ldots, Q_n$, each $Q_i$ with a…

Computational Geometry · Computer Science 2024-03-26 Sándor P. Fekete , Phillip Keldenich , Dominik Krupke , Stefan Schirra

We study convex polyhedra in $\mathbb{R}\mathbb{P}^3$ with all their vertices on a sphere. We do not require, in particular, that the polyhedra lie in the interior of the sphere, hence the term "weakly inscribed". Such polyhedra can be…

Metric Geometry · Mathematics 2020-02-05 Hao Chen , Jean-Marc Schlenker