Interior curvature estimate for curvature quotient equations on convex hypersurfaces
Jianxiang Liu
TL;DR
This work establishes interior $C^2$ estimates for convex hypersurfaces in $\mathbb{R}^{n+1}$ that satisfy the curvature quotient equation $F(\lambda)=\frac{\sigma_n}{\sigma_{n-2}}(\lambda)=f(X)>0$ with $n\ge 3$. Building on the Hessian quotient framework, the authors develop a pointwise Jacobi inequality on Riemannian manifolds and combine it with Guan–Qiu-type auxiliary functions, performing a careful case analysis to bound principal curvatures without resorting to Legendre transforms. The main result is a local bound $\sup_{B_{r/2}}|\lambda_i|\le C$ depending on $n$, $r$, and data from $f$ and the hypersurface, contributing to the regularity theory for curvature quotient equations on convex graphs. The approach broadens the toolbox for interior curvature estimates and offers a pathway toward higher-dimensional results for Hessian quotient equations.
Abstract
We study interior curvature estimates for convex graphs which satisfy the quotient equation $\frac{σ_{n}}{σ_{n-2}}(λ)=f(X)>0$ in this paper.
