Complete Classification of the Symmetry Group of $L_p$-Minkowski Problem on the Sphere
Huan-Jie Chen, Shi-Zhong Du
TL;DR
The paper addresses the symmetry classification of the $L_p$-Minkowski problem on the sphere by projecting the spherical equation to a Euclidean Monge–Ampère form and applying Lie group analysis to determine all invariant transformations. The main approach combines a semi-spherical projection to reduce to $\det D^2u=(1+|x|^2)^{-(p+n+1)/2}u^{p-1}$, a thorough Lie symmetry study to extract infinitesimal generators, and a reconstruction of corresponding convex-body transformations. The key contributions are an explicit, complete classification of the symmetry group across all real $p$: rotations and scalings for $p=n+1$, rotations and translations for $p=1$, centro-affine for $p=-n-1$, and rotations for other $p$, together with a global–local compatibility framework. This symmetry atlas enhances understanding of the geometric structure of the $L_p$-Minkowski problem and informs symmetry-based solution strategies in convex geometry.
Abstract
In Convex Geometry, a core topic is the $L_p$-Minkowski problem \begin{equation}\label{e0.1} \det(\nabla^2h+hI)=fh^{p-1}, \ \ \forall X\in{\mathbb{S}}^n, \ \ \forall p\in \mathbb{R} \end{equation} of Monge-Ampère type. By the transformation $u(x)=h(X)\sqrt{1+|x|^2}$ and semi-spherical projection, equation \eqref{e0.1} can be reformulated by the Monge-Ampère type equation \begin{equation}\label{e0.2} \det D^2u=(1+|x|^2)^{-\frac{p+n+1}{2}}u^{p-1}, \ \ \forall x\in{\mathbb{R}}^n, \ \ \forall p\in \mathbb{R} \end{equation} on the Euclidean space. In this paper, we will firstly determine the symmetric groups of $n$-dimensional fully nonlinear equation \eqref{e0.2} without asymptotic growth assumption. After proving several key resolution lemmas, we thus completely classify the symmetric groups of the $L_p$-Minkowski problem. Our method develops the Lie theory to fully nonlinear PDEs in Convex Geometry.
