The capillary Christoffel-Minkowski problem
Xinqun Mei, Guofang Wang, Liangjun Weng
TL;DR
The paper advances the capillary Christoffel-Minkowski problem by introducing a $k$-th capillary area measure for capillary convex bodies in the half-space and reformulating the problem as a Hessian equation with Robin boundary. Using the method of continuity, it proves existence and uniqueness of a strictly convex capillary hypersurface whose capillary area measure matches a prescribed function under a natural connectivity condition in a weighted function class. Central to the approach are new a priori estimates (C^0, gradient, and C^2) for the Hessian equation, convexity preservation via Guan-Ma’s constant rank theorem, and a compatibility orthogonality condition. The results extend capillary Minkowski-type theory to intermediate $k$-th measures and rely on capillary Steiner formulas and oblique boundary estimates to handle the Robin boundary.
Abstract
In this article, we introduce a $k$-th capillary area measure for capillary convex bodies in the Euclidean half-space, which serves as a boundary counterpart to the classical concept of area measure (see, e.g., \cite[Chapter 8]{Sch}). We then propose a Christoffel-Minkowski problem for capillary convex bodies, to find a capillary convex body in the Euclidean half-space with a prescribed $k$-th capillary area measure. This problem is equivalent to solving a Hessian-type equation with a Robin boundary value condition. We then establish the existence and uniqueness of a smooth solution under a natural sufficient condition.
