A Green's function approach to linearized Monge-Ampère equations in divergence form and application to singular Abreu type equations
Chong Gu, Nam Q. Le
TL;DR
This work addresses regularity for linearized Monge–Ampère equations in divergence form, where the coefficient matrix arises from the cofactor of the Hessian of a convex potential with Hessian determinant bounded away from zero. The authors develop sharp Lorentz-space estimates for the Green's function and its gradient, and leverage these to obtain interior and global Harnack and Hölder estimates for solutions to $L_u v = \mathrm{div}\mathbf F + \mu$, under data in Lorentz/L^p classes. A central contribution is the transfer of Green-function bounds into robust regularity results, including global Hölder estimates up to the boundary and, crucially, solvability results for singular Abreu-type fourth-order equations in all dimensions. The results extend previous affine-invariant regularity theory to all dimensions, handle measure-right-hand sides with controlled growth, and enable solvability of challenging Abreu-type problems by providing a priori Hessian bounds and higher-order estimates.
Abstract
In this paper, we establish local and global regularity estimates for linearized Monge-Ampère equations in divergence form via critical Lorentz space estimates for the Green's function of the linearized Monge-Ampère operator and its gradient. These estimates hold under suitable conditions on the data and the convex Monge-Ampère potential is assumed to have Hessian determinant bounded between two positive constants. As an application, we obtain the solvability in all dimensions of the second boundary value problem for a class of singular fourth-order Abreu type equations that arise from the approximation analysis of variational problems subject to convexity constraints.
