An iterative construction of complete Kähler--Einstein metrics
Quang-Tuan Dang, Tat Dat Tô
TL;DR
The paper develops a noncompact counterpart to Tsuji's iterative construction for complete Kähler–Einstein metrics with negative curvature under bounded geometry. By leveraging a uniform Bergman kernel expansion, it proves convergence of the iteration to a solution of $(dd^c phi_infty)^n = e^{phi_infty-phi_L}\u039f$ and obtains explicit rates, with faster convergence in the Kähler–Einstein case. It then shows that fiberwise KE metrics induce a positively curved metric on the relative canonical bundle $K_{X/Y}$ and that this positivity extends across singular fibers; the framework also handles cusp and mixed cone singularities and yields plurisubharmonic variation in families, including bounded pseudoconvex domains. Collectively, the results broaden KE metric variation theory to noncompact, bounded-geometry settings and provide tools for canonical metric constructions in fibred and degenerating settings.
Abstract
We extend Tsuji's iterative construction of complete Kähler--Einstein metrics with negative scalar curvature to noncompact Kähler manifolds with bounded geometry, using Berndtsson's method from the compact setting. Consequently, given a holomorphic surjective map $p:X\to Y$, where $X$ is a weakly pseudoconvex Kähler manifold and $Y$ is a complex manifold, and where the smooth fibers admit Kähler--Einstein metrics with negative scalar curvature and bounded geometry, we show that the fiberwise Kähler--Einstein metrics induce a semipositively curved metric on the relative canonical bundle $K_{X/Y}$. Moreover, our approach also applies to the plurisubharmonic variation of cusp Kähler--Einstein metrics.
