English
Related papers

Related papers: On bodies with congruent sections or projections

200 papers

In 1959, Klee proved that a convex body $K$ is a polyhedron if and only if all of its projections are polygons. In this paper, a new proof of this theorem is given for convex bodies in $\mathbb{R}^3$.

Metric Geometry · Mathematics 2015-03-06 John J. Zanazzi

A $\sqrt{n}$ estimate in the hyperplane problem with arbitrary measures has recently been proved in \cite{K3}. In this note we present analogs of this result for sections of lower dimensions and in the complex case. We deduce these…

Metric Geometry · Mathematics 2013-09-26 Alexander Koldobsky

We obtain a new extension of Rogers-Shephard inequality providing an upper bound for the volume of the sum of two convex bodies $K$ and $L$. We also give lower bounds for the volume of the $k$-th limiting convolution body of two convex…

Metric Geometry · Mathematics 2013-12-23 David Alonso-Gutiérrez , Bernardo González , Carlos Hugo Jiménez

Let $K$ and $L$ be two convex bodies in $\mathbb R^n$, $n\geq 3$, with $L\subset \text{int}\, K$. In this paper we prove the following result: if every two parallel chords of $K$, supporting $L$ have the same length, then $K$ and $L$ are…

We survey results on the problem of covering the space ${\mathbb R}^n$, or a convex body in it, by translates of a convex body. Our main goal is to present a diverse set of methods. A theorem of Rogers is a central result, according to…

Metric Geometry · Mathematics 2016-03-16 Márton Naszódi

The covariogram g_K(x) of a convex body K \subseteq E^d is the function which associates to each x \in E^d the volume of the intersection of K with K+x. Matheron asked whether g_K determines K, up to translations and reflections in a point.…

Metric Geometry · Mathematics 2007-05-23 Gennadiy Averkov , Gabriele Bianchi

One of the most important problems in Geometric Tomography is to establish properties of a given convex body if we know some properties over its sections or its projections. There are many interesting and deep results that provide…

It is proved that if $C$ is a convex body in ${\Bbb R}^n$ then $C$ has an affine image $\widetilde C$ (of non-zero volume) so that if $P$ is any 1-codimensional orthogonal projection, $$|P\widetilde C| \ge |\widetilde C|^{n-1\over n}.$$ It…

Metric Geometry · Mathematics 2016-09-06 Keith Ball

Two conjectures recently proposed by one of the authors are disproved

Metric Geometry · Mathematics 2011-05-25 P. G. L. Porta Mana , P. G. Lewis

We study relations of some classes of $k$-convex, $k$-visible bodies in Euclidean spaces. We introduce and study \textrm{circular projections} in normed linear spaces and classes of bodies related with families of such maps, in particular,…

Metric Geometry · Mathematics 2015-12-31 V. Golubyatnikov V. Rovenski

The main goal of this paper is to present a series of inequalities connecting the surface area measure of a convex body and surface area measure of its projections and sections. We present a solution of a question from S. Campi, P.…

Metric Geometry · Mathematics 2017-08-29 Alexander Koldobsky , Christos Saroglou , Artem Zvavitch

We prove several stability and volume difference inequalities for projections of convex bodies and apply them to prove a hyperplane inequality for surface area of projection bodies.

Metric Geometry · Mathematics 2015-06-16 Alexander Koldobsky

In this paper we study the following geometric problem: given $2^n-1$ real numbers $x_A$ indexed by the non-empty subsets $A\subset \{1,..,n\}$, is it possible to construct a body $T\subset \mathbb{R}^n$ such that $x_A=|T_A|$ where $|T_A|$…

Combinatorics · Mathematics 2019-10-29 Imre Leader , Žarko Ranđelović , Eero Räty

We provide an affirmative answer to a problem posed by Barvinok and Veomett, showing that in general an n-dimensional convex body cannot be approximated by a projection of a section of a simplex of a sub-exponential dimension. Moreover, we…

Functional Analysis · Mathematics 2012-09-28 Alexander E. Litvak , Mark Rudelson , Nicole Tomczak-Jaegermann

Let $\mathcal{P}$ be a set of points in the plane, and $\mathcal{S}$ a strictly convex set of points. In this note, we show that if $\mathcal{P}$ contains many translates of $\mathcal{S}$, then these translates must come from a generalized…

Combinatorics · Mathematics 2023-02-28 Gabriel Currier , Jozsef Solymosi , Ethan Patrick White

We introduce the problem of partitioning 2D regions (usually convex regions) into mutually congruent pieces ('tiles').

Combinatorics · Mathematics 2010-08-03 R. Nandakumar

We discuss a construction that gives counterexamples to various questions of unique determination of convex bodies.

Metric Geometry · Mathematics 2012-01-04 Dmitry Ryabogin , Vlad Yaskin

We prove the following theorem. Let $\mu$ be a measure on $R^n$ with even continuous density, and let $K,L$ be origin-symmetric convex bodies in $R^n$ so that $\mu(K\cap H)\le \mu(L\cap H)$ for any central hyperplane H. Then $\mu(K)\le…

Functional Analysis · Mathematics 2014-05-22 Alexander Koldobsky , Artem Zvavitch

Let $K$ be a convex body in an affine chart of the $n$ dimensional real Projective space $\mathbb{RP}^n$, $n \geq 3$, let $H$ be a hyperplane which is not a support hyperplane of $K$ and let $p_1,p_2 \in \mathbb{RP}^n \setminus H$ be two…

Metric Geometry · Mathematics 2026-05-07 Efrén Morales-Amaya

The illumination conjecture is a classical open problem in convex and discrete geometry, asserting that every compact convex body~$K$ in $\mathbb R^n$ can be illuminated by a set of no more than $2^n$ points. If $K$ has smooth boundary, it…

Metric Geometry · Mathematics 2025-03-31 Lenny Fukshansky