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We generalize the classical Hardy and Faber-Krahn inequalities to arbitrary functions on a convex body $\Omega \subset \mathbb{R}^n$, not necessarily vanishing on the boundary $\partial \Omega$. This reduces the study of the Neumann…

Spectral Theory · Mathematics 2015-08-14 Alexander V. Kolesnikov , Emanuel Milman

For a permutationally invariant unconditional convex body K in R^n we define a finite sequence (K_j), j = 1, ..., n of projections of the body K to the space spanned by first j vectors of the standard basis of R^n. We prove that the…

Functional Analysis · Mathematics 2013-03-04 Piotr Nayar , Tomasz Tkocz

We find that for any n-dimensional, compact, convex subset K of R^{n+1} there is an affinely-spherical hypersurface M in R^{n+1} with center at the relative interior of K, such that the disjoint union of M and K is the boundary of an…

Differential Geometry · Mathematics 2015-12-15 Bo'az Klartag

We prove new $L_p$ affine isoperimetric inequalities for all $ p \in [-\infty,1)$. We establish, for all $p\neq -n$, a duality formula which shows that $L_p$ affine surface area of a convex body $K$ equals $L_\frac{n^2}{p}$ affine surface…

Metric Geometry · Mathematics 2010-07-09 Elisabeth Werner , Deping Ye

We introduce an (equi-)affine invariant diffusion geometry by which surfaces that go through squeeze and shear transformations can still be properly analyzed. The definition of an affine invariant metric enables us to construct an invariant…

Computer Vision and Pattern Recognition · Computer Science 2010-12-30 Dan Raviv , Alexander M. Bronstein , Michael M. Bronstein , Ron Kimmel , Nir Sochen

In this paper, we show that the \alpha_{m,2}-invariant of a smooth cubic surface with Eckardt points is strictly bigger than 2/3. This can be used to simplify Tian's original proof of the existence of Kaehler-Einstein metrics on such…

Algebraic Geometry · Mathematics 2009-11-12 Yalong Shi

There exist several interesting results in the literature on subnormal operator tuples having their spectral properties tied to the geometry of strictly pseudoconvex domains or to that of bounded symmetric domains in $\C^n$. We introduce a…

Functional Analysis · Mathematics 2016-12-20 Ameer Athavale

We introduce f-divergence, a concept from information theory and statistics, for convex bodies in R^n. We prove that f-divergences are SL(n) invariant valuations and we establish an affine isoperimetric inequality for these quantities. We…

Functional Analysis · Mathematics 2012-05-16 Elisabeth M. Werner

It was shown in [11] that for every origin-symmetric star body $K \subseteq \mathbb R^n$ of volume $1$, every even continuous probability density $f$ on $K$ and $1 \leq k \leq n-1$, there exists a subspace $F \subseteq \mathbb R^n$ of…

Metric Geometry · Mathematics 2024-11-07 J. Haddad

Let $K \subset {\mathbb R}^2$ be an $o$-symmetric convex body, and $K^*$ its polar body. Then we have $|K|\cdot |K^*| \ge 8$, with equality if and only if $K$ is a parallelogram. ($| \cdot |$ denotes volume). If $K \subset {\mathbb R}^2$ is…

Metric Geometry · Mathematics 2015-07-07 K. J. Böröczky , E. Makai , M. Meyer , S. Reisner

Motivated by the Blaschke-Santal\'o inequality, we define for a convex body K in ${\bf R}^n$ and for $t \in {\bf R}$ the Santal\'o-regions S(K,t) of K. We investigate properties of these sets and relate them to a concept of Affine…

Metric Geometry · Mathematics 2016-09-07 Mathieu Meyer , Elisabeth Werner

This paper is devoted to the complete classification of space curves under affine transformations in the view of Cartan's theorem. Spivak has introduced the method but has not found the invariants. Furthermore, for the first time, we…

Differential Geometry · Mathematics 2012-01-11 Mehdi Nadjafikhah , Ali Mahdipour Shirayeh

Zhang's reverse affine isoperimetric inequality states that among all convex bodies $K\subseteq\mathbb{R}^n$, the affine invariant quantity $|K|^{n-1}|\Pi^*(K)|$ (where $\Pi^*(K)$ denotes the polar projection body of $K$) is minimized if…

Functional Analysis · Mathematics 2018-10-18 David Alonso-Gutiérrez , Julio Bernués , Bernardo González Merino

This paper explores equi-centro-affine extremal hypersurfaces in an ellipsoid. By analyzing the evolution of invariant submanifold flows under centro-affine unimodular transformations, we derive the first and second variational formulas for…

Differential Geometry · Mathematics 2025-01-31 Yun Yang , Changzheng Qu

Let us denote by $\mathcal K_n$ the hyperspace of all convex bodies of $\mathbb R^n$ equipped with the Hausdorff distance topology. An affine invariant point $p$ is a continuous and Aff(n)-equivariant map $p:\mathcal K_n\to \mathbb R^n$,…

Geometric Topology · Mathematics 2016-02-23 Natalia Jonard-Pérez

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

We study the arithmetic of Galois-invariant sets of points on algebraic curves with controlled reduction behavior. Let $C$ be a smooth projective curve with a smooth proper model $\mathcal{C}$ over $\mathcal{O}_{K,S}$. We define $\Omega_n$…

Number Theory · Mathematics 2026-04-02 Fatemehzahra Janbazi , Fateme Sajadi

In this work we present a theorem regarding two convex bodies $K_1, K_2\subset \mathbb{R}^{n}$, $n\geq 3$, and two families of sections of them, given by two families of tangent planes of two spheres $S_i\subset \textrm{int}\textrm{ } K_i$,…

Metric Geometry · Mathematics 2025-08-21 Efren Morales-Amaya

A Fourier restriction estimate is obtained for a broad class of conic surfaces by adding a weight to the usual underlying measure. The new restriction estimate exhibits a certain affine-invariance and implies the sharp $L^p-L^q$ restriction…

Classical Analysis and ODEs · Mathematics 2019-02-20 Jonathan Hickman

We prove new Alexandrov-Fenchel type inequalities and new affine isoperimetric inequalities for mixed $p$-affine surface areas. We introduce a new class of bodies, the illumination surface bodies, and establish some of their properties. We…

Metric Geometry · Mathematics 2010-07-09 Elisabeth Werner , Deping Ye