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Anisotropic fractional area measures

Xiaxing Cai

TL;DR

This work introduces the anisotropic $s$-fractional area measures $\mathcal{A}_s(K,L,\cdot)$ as the first variation of the anisotropic $s$-perimeter $P_s(K,L)$ with respect to perturbations of $K$, linking fractional perimeters to classical convex-geometry invariants. It proves a sharp variational formula, derives limiting relations $s\mathcal{A}_s(K,L,\cdot)\to \frac{|L|}{2}S_{n-1}(K,\cdot)$ as $s\to 0^+$ and $(1-s)\mathcal{A}_s(K,L,\cdot)\to S_{n-2}(K,ZL,\cdot)$ as $s\to 1^-$ for smooth $K$, and solves the Minkowski problem for these measures in full generality. The paper also provides a variational route to a Monge–Ampère reformulation in the smooth setting and gives a necessary condition for the convexity of optimizers in the anisotropic fractional isoperimetric inequality, tying together dual mixed volumes, chord measures, and moment bodies. Overall, it extends classical convex-geometry concepts to a fractional, anisotropic setting, enabling new isoperimetric-type results and measure-based characterizations.

Abstract

The anisotropic $s$-fractional area measures are introduced as the first variation of the anisotropic fractional $s$-perimeter $P_s(K,L)$, with $L$ an origin symmetric convex body and $s\in(0,1)$. As $s\rightarrow 1^-$, the anisotropic $s$-fractional area measure converges to the mixed area measure of $K$ and the moment body of $L$. The Minkowski problem of these measures are solved. Finally, a necessary condition for the convexity of optimizers in the anisotropic fractional isoperimetric inequality is derived.

Anisotropic fractional area measures

TL;DR

This work introduces the anisotropic -fractional area measures as the first variation of the anisotropic -perimeter with respect to perturbations of , linking fractional perimeters to classical convex-geometry invariants. It proves a sharp variational formula, derives limiting relations as and as for smooth , and solves the Minkowski problem for these measures in full generality. The paper also provides a variational route to a Monge–Ampère reformulation in the smooth setting and gives a necessary condition for the convexity of optimizers in the anisotropic fractional isoperimetric inequality, tying together dual mixed volumes, chord measures, and moment bodies. Overall, it extends classical convex-geometry concepts to a fractional, anisotropic setting, enabling new isoperimetric-type results and measure-based characterizations.

Abstract

The anisotropic -fractional area measures are introduced as the first variation of the anisotropic fractional -perimeter , with an origin symmetric convex body and . As , the anisotropic -fractional area measure converges to the mixed area measure of and the moment body of . The Minkowski problem of these measures are solved. Finally, a necessary condition for the convexity of optimizers in the anisotropic fractional isoperimetric inequality is derived.

Paper Structure

This paper contains 10 sections, 14 theorems, 139 equations.

Key Result

Theorem 1.1

Let $s\in(0,1)$. Suppose $\mu$ is a finite Borel measure on ${\mathbb S}^{n-1}$ and $L\subset\mathbb R^n$ is an origin symmetric convex body. There is a convex body $K\subset\mathbb R^n$ such that $\mu=\mathcal{A}_s(K,L,\cdot)$ if and only if $\mu$ is not concentrated in any subsphere and

Theorems & Definitions (26)

  • Theorem 1.1
  • Definition 3.1
  • Lemma 3.2
  • Lemma 3.3
  • proof
  • Theorem 3.4
  • proof
  • Lemma 3.5
  • Lemma 3.6
  • proof
  • ...and 16 more