arXiv subjects

Jesús Yepes Nicolás

Publications and source records attributed to Jesús Yepes Nicolás.

11 recordsLinked to original sources

arXiv2026

On a Brunn-Minkowski principle for first-order information functionals

In this work we present the following general principle: every positive homogeneous functional on an abstract convex cone satisfying a suitable Brunn-Minkowski inequality gives rise to an information functional -defined as the quotient of the functional by its relative surface area- that satisfies a linear Brunn-Minkowski inequality. We also establish the dual counterpart of this principle for functionals satisfying an analogous convexity property, yielding reverse linear Brunn-Minkowski inequalities for the associated information functionals. Furthermore, we show that homogeneity is necessary within this principle by providing a counterexample to the expected result for the information functional associated to the standard Gaussian measure. As applications, we recover, via a different, first-order argument, a classical result by Giannopoulos, Hartzoulaki and Paouris (2002) for the ratio of two consecutive quermassintegrals, together with a characterization of the equality case. The same argument extends to the setting of mixed discriminants of symmetric positive definite matrices. Finally, our approach also yields a new $L_p$ extension ($p \geq 1$) of the Brunn-Minkowski inequality by Dembo, Cover and Thomas for the classical information functional, where the relative surface area is expressed in terms of Lutwak's first $L_p$ quermassintegral.

math.MG↗

arXiv2025

On $L_p$ Brunn-Minkowski type inequalities for a general class of functionals

In this work, the $L_p$ version (for $p> 1$) of the dimensional Brunn-Minkowski inequality for the standard Gaussian measure $γ_n(\cdot)$ on $\mathbb{R}^n$ is shown. More precisely, we prove that for any $0$-symmetric convex sets with nonempty interior, any $p>1$, and every $λ\in (0,1)$, \[ γ_n\bigl((1-λ)\cdot K+_p λ\cdot L\bigr)^{p/n} \geqslant (1-λ) γ_n(K)^{p/n} + λγ_n(L)^{p/n}, \] with equality, for some $λ\in (0,1)$ and $p>1$, if and only if $K=L$. This result, recently established without the equality conditions by Hosle, Kolesnikov and Livshyts, by using a different and functional approach, turns out to be the $L_p$ extension of a celebrated result for the Minkowski sum (that is, for $p=1$) by Eskenazis and Moschidis (2021) on a problem by Gardner and Zvavitch (2010). Moreover, an $L_p$ Brunn-Minkowski type inequality is obtained for the classical Wills functional $\mathcal{W}(\cdot)$ of convex bodies. These results are derived as a consequence of a more general approach, which provides us with other remarkable examples of functionals satisfying $L_p$ Brunn-Minkowski type inequalities, such as different absolutely continuous measures with radially decreasing densities.

math.MG↗

arXiv2024

A general functional version of Grünbaum's inequality

A classical inequality by Grünbaum provides a sharp lower bound for the ratio $\mathrm{vol}(K^{-})/\mathrm{vol}(K)$, where $K^{-}$ denotes the intersection of a convex body with non-empty interior $K\subset\mathbb{R}^n$ with a halfspace bounded by a hyperplane $H$ passing through the centroid $\mathrm{g}(K)$ of $K$. In this paper we extend this result to the case in which the hyperplane $H$ passes by any of the points lying in a whole uniparametric family of $r$-powered centroids associated to $K$ (depending on a real parameter $r\geq0$), by proving a more general functional result on concave functions. The latter result further connects (and allows one to recover) various inequalities involving the centroid, such as a classical inequality (due to Minkowski and Radon) that relates the distance of $\mathrm{g}(K)$ to a supporting hyperplane of $K$, or a result for volume sections of convex bodies proven independently by Makai Jr. & Martini and Fradelizi.

math.MG↗

arXiv2022

On Rogers-Shephard type inequalities for the lattice point enumerator

In this paper we study various Rogers-Shephard type inequalities for the lattice point enumerator $\mathrm{G}_{n}(\cdot)$ on $\mathbb{R}^n$. In particular, for any non-empty convex bounded sets $K,L\subset\mathbb{R}^n$, we show that \[\mathrm{G}_{n}(K+L)\mathrm{G}_{n}\bigl(K\cap(-L)\bigr) \leq\binom{2n}{n} \mathrm{G}_{n}\bigl(K+(-1,1)^n\bigr)\mathrm{G}_{n}\bigl(L+(-1,1)^n\bigr). \] and \[ \mathrm{G}_{n-k}(P_{H^\perp} K)\mathrm{G}_{k}(K\cap H)\leq\binom{n}{k}\mathrm{G}_{n}\bigl(K+(-1,1)^n\bigr), \] for $H=\mathrm{lin}\{\mathrm{e}_1,\dots,\mathrm{e}_k\}$, $k\in\{1,\dots,n-1\}$. Additionally, a discrete counterpart to a classical result by Berwald for concave functions, from which other discrete Rogers-Shephard type inequalities may be derived, is shown. Furthermore, we prove that these new discrete analogues for $\mathrm{G}_{n}(\cdot)$ imply the corresponding results involving the Lebesgue measure.

math.MG↗

arXiv2021

On discrete $L_p$ Brunn-Minkowski type inequalities

$L_p$ Brunn-Minkowski type inequa\-li\-ties for the lattice point enumerator $\mathrm{G}_n(\cdot)$ are shown, both in a geometrical and in a functional setting. In particular, we prove that \[\mathrm{G}_n\bigl((1-λ)\cdot K +_p λ\cdot L + (-1,1)^n\bigr)^{p/n}\geq (1-λ)\mathrm{G}_n(K)^{p/n}+λ\mathrm{G}_n(L)^{p/n}\] for any $K, L\subset\mathbb{R}^n$ bounded sets with integer points and all $λ\in(0,1)$. We also show that these new discrete analogues (for $\mathrm{G}_n(\cdot)$) imply the corresponding results concerning the Lebesgue measure.

math.MG↗

arXiv2020

Brunn-Minkowski type inequalities for the lattice point enumerator

Geometric and functional Brunn-Minkowski type inequalities for the lattice point enumerator $\mathrm{G}_n(\cdot)$ are provided. In particular, we show that $$\mathrm{G}_n((1-λ)K + λL + (-1,1)^n)^{1/n}\geq (1-λ)\mathrm{G}_n(K)^{1/n}+λ\mathrm{G}_n(L)^{1/n}$$ for any non-empty bounded sets $K, L\subset\mathbb{R}^n$ and all $λ\in(0,1)$. We also show that these new discrete versions imply the classical results, and discuss some links with other related inequalities.

math.MG↗

arXiv2020

On a reverse isoperimetric inequality for relative outer parallel bodies

We show a reverse isoperimetric inequality within the class of relative outer parallel bodies, with respect to a general convex body $E$, along with its equality condition. Based on the convexity of the sequence of quermassintegrals of Minkowski sums we also prove further inequalities.

math.MG↗

arXiv2020

Further inequalities for the (generalized) Wills functional

The Wills functional $\mathcal{W}(K)$ of a convex body $K$, defined as the sum of its intrinsic volumes $\mathrm{V}_i(K)$, turns out to have many interesting applications and properties. In this paper we make profit of the fact that it can be represented as the integral of a log-concave function, which, furthermore, is the Asplund product of other two log-concave functions, and obtain new properties of the Wills functional (indeed, we will work in a more general setting). Among others, we get upper bounds for $\mathcal{W}(K)$ in terms of the volume of $K$, as well as Brunn-Minkowski and Rogers-Shephard type inequalities for this functional. We also show that the cube of edge-length 2 maximizes $\mathcal{W}(K)$ among all $0$-symmetric convex bodies in John position, and we reprove the well-known McMullen inequality $\mathcal{W}(K)\leq e^{\mathrm{V}_1(K)}$ using a different approach.

math.MG↗

arXiv2018

On Rogers-Shephard type inequalities for general measures

In this paper we prove a series of Rogers-Shephard type inequalities for convex bodies when dealing with measures on the Euclidean space with either radially decreasing densities, or quasi-concave densities attaining their maximum at the origin. Functional versions of classical Rogers-Shephard inequalities are also derived as consequences of our approach.

math.MG↗

arXiv2017

Brunn-Minkowski inequalities in product metric measure spaces

Given one metric measure space $X$ satisfying a linear Brunn-Minkowski inequality, and a second one $Y$ satisfying a Brunn-Minkowski inequality with exponent $p\ge -1$, we prove that the product $X\times Y$ with the standard product distance and measure satisfies a Brunn-Minkowski inequality of order $1/(1+p^{-1})$ under mild conditions on the measures and the assumption that the distances are strictly intrinsic. The same result holds when we consider restricted classes of sets. We also prove that a linear Brunn-Minkowski inequality is obtained in $X\times Y$ when $Y$ satisfies a Prékopa-Leindler inequality. In particular, we show that the classical Brunn-Minkowski inequality holds for any pair of weakly unconditional sets in $\mathbb{R}^n$ (i.e., those containing the projection of every point in the set onto every coordinate subspace) when we consider the standard distance and the product measure of $n$ one-dimensional real measures with positively decreasing densities. This yields an improvement of the class of sets satisfying the Gaussian Brunn-Minkowski inequality. Furthermore, associated isoperimetric inequalities as well as recently obtained Brunn-Minkowski's inequalities are derived from our results.

math.MG↗

arXiv2015

On a linear refinement of the Prékopa-Leindler inequality

If $f,g:\mathbb{R}^n\longrightarrow\mathbb{R}_{\geq0}$ are non-negative measurable functions, then the Prékopa-Leindler inequality asserts that the integral of the Asplund sum (provided that it is measurable) is greater or equal than the $0$-mean of the integrals of $f$ and $g$. In this paper we prove that under the sole assumption that $f$ and $g$ have a common projection onto a hyperplane, the Prékopa-Leindler inequality admits a linear refinement. Moreover, the same inequality can be obtained when assuming that both projections (not necessarily equal as functions) have the same integral. An analogous approach may be also carried out for the so-called Borell-Brascamp-Lieb inequality.

math.FA↗