Independence of Singularity Type for Numerically Effective Kähler-Ricci Flows
Hosea Wondo, Zhou Zhang
TL;DR
The paper proves that for a compact Kähler manifold with nef canonical bundle, the long-time singularity type of the normalised Kähler-Ricci flow is independent of the initial metric: if one solution is Type III, all are Type III, and similarly for Type IIb. The authors develop a framework that uses a Monge–Ampère reduction to compare an arbitrary solution with a Type III reference flow, establishing metric equivalence and transferring curvature bounds. They first analyze the special case of flows starting from a scaled initial metric, then extend to general higher-order estimates via a maximum-principle argument on a tensor measuring the difference of connections, ensuring uniform curvature control. These results generalize prior semi-ample cases and bolster the understanding of the infinite-time behavior of Kähler-Ricci flows on nef manifolds, with implications for the abundance conjecture and collapsing phenomena in related geometric settings.
Abstract
In this paper, we show that the singularity type of solutions to the Käher-Ricci flow on a numerically effective manifold does not depend on the initial metric. More precisely if there exists a type III solution to the Kähler-Ricci flow, then any other solution starting from a different initial metric will also be Type III. This generalises previous results by Y. Zhang for the semi-ample case.
