A fully nonlinear locally constrained curvature flow for capillary hypersurface
Xinqun Mei, Liangjun Weng
TL;DR
The paper introduces a locally constrained fully nonlinear curvature flow for convex capillary hypersurfaces in the half-space, aiming to unify and extend Alexandrov-Fenchel-type results via an evolution approach. The flow uses the curvature function $F=H_k^{1/k}$ with capillary boundary conditions, preserves convexity, and exists for all time, with smooth convergence to a spherical cap; a high-order capillary isoperimetric ratio is shown to be monotone along the flow. Central to the analysis are derived evolution equations, reduction to a scalar oblique PDE on star-shaped hypersurfaces, and a suite of $C^0$, $C^1$, and curvature estimates that yield global existence and convergence. As a byproduct, the monotonicity of quermassintegrals along the flow yields Alexandrov-Fenchel inequalities for capillary hypersurfaces in the half-space, with equality characterized by spherical caps.
Abstract
In this article, we study a locally constrained fully nonlinear curvature flow for convex capillary hypersurfaces in half-space. We prove that the flow preserves the convexity, exists for all time, and converges smoothly to a spherical cap. This can be viewed as the fully nonlinear counterpart of the result in \cite{MWW}. As a byproduct, a high-order capillary isoperimetric ratio (1.6) evolves monotonically along this flow, which yields a class of the Alexandrov-Fenchel inequalities.
