Stability of Hyperkähler Flow
Kuan-Hui Lee
TL;DR
The paper studies the stability of Donaldson's hyperkähler flow (H-flow) for surfaces in hyperkähler 4-manifolds, extending dynamic stability results from mean curvature flow to this setting. It establishes the gradient-flow structure via the hyperkähler energy $E(f)=\int_S \lambda^2\,\rho$, derives evolution equations for the metric, volume form, and second fundamental form, and introduces the special H-flow constrained by $f^*(\theta)=\rho$ with $\theta=\overline{\omega}_2+i\overline{\omega}_3$. The central result shows that if a Lagrangian surface $\Gamma$ lies close to a compact, strongly stable complex Lagrangian $\Sigma$ (e.g., the zero section in the Eguchi–Hanson space), then the special H-flow exists for all time and converges smoothly to $\Sigma$, with convergence rate governed by $C^0$, $C^1$, and energy-type estimates. The analysis combines tubular-neighborhood geometry, precise control of the second fundamental form, and maximum-principle arguments to demonstrate long-time existence and smooth convergence, providing a robust stability framework for hyperkähler flows in dimension four.
Abstract
In this work, we discuss the stability of Donaldson's flow of surfaces in a hyperkähler 4-manifold. In \cite{WT2}, Wang and Tsai proved a uniqueness theorem and $C^1$ dynamic stability theorem of the mean curvature flow for minimal surface. We extend their results and obtain a similar dynamic stability theorem of the hyperkähler flow.
