On a generalized Monge-Ampère equation on closed almost Kähler surfaces
Ken Wang, Zuyi Zhang, Tao Zheng, Peng Zhu
TL;DR
This work extends Calabi-Yau theory to closed almost Kähler surfaces by formulating a generalized Monge-Ampère equation $(\omega + \mathcal{D}_J^+(\varphi))^2 = e^{f}\omega^2$ and solving for a smooth potential $\varphi$. The central tool is the operator $\mathcal{D}_J^+$, a generalization of $\partial_J\bar{\partial}_J$, enabling a Yau-type existence and uniqueness theory in the almost Kähler setting. The authors develop a full a priori estimate program, including a $C^0$ bound and higher-order estimates, via the continuity method and local Darboux coordinates, to obtain a smooth solution with $\varphi \in C^{\infty}(M,J)_0$. As an application, they verify Donaldson's tameness conjecture for certain taming symplectic forms on almost complex 4-manifolds by producing uniform bounds along the solution path. The results broaden Calabi-Yau theory beyond Kähler geometry and provide new tools for the study of tamed almost complex 4-manifolds.
Abstract
We show the existence and uniqueness of solutions to a generalized Monge-Ampère equation on closed almost Kähler surfaces, where the equation depends only on the underlying almost Kähler structure. As an application, we prove Donaldson's conjecture for tamed almost complex 4-manifolds.
