We prove the existence of Kahler-Einstein metrics on Q-Gorenstein smoothable, K-polystable Q-Fano varieties, and we show how these metrics behave, in the Gromov-Hausdorff sense, under Q-Gorenstein smoothings.
The existence of emph{weak conical Kahler-Einstein} metrics along smooth hypersurfaces with angle between $0$ and $2pi$ is obtained by studying a smooth continuity method and a emph{local Mosers iteration} technique. In the case of negative and zero
Ricci curvature, the $C^0$ estimate is unobstructed; while in the case of positive Ricci curvature, the $C^0$ estimate obstructed by the properness of the emph{twisted K-Energy}. As soon as the $C^0$ estimate is achieved, the local Moser iteration could improve the emph{rough bound} on the approximations to a emph{uniform $C^2$ bound}, thus produce a emph{weak conical Kahler-Einstein} metric. The method used here do not depend on the bound of any background conical Kahler metrics.
We study the generalized Kahler-Ricci flow with initial data of symplectic type, and show that this condition is preserved. In the case of a Fano background with toric symmetry, we establish global existence of the normalized flow. We derive an exten
sion of Perelmans entropy functional to this setting, which yields convergence of nonsingular solutions at infinity. Furthermore, we derive an extension of Mabuchis $K$-energy to this setting, which yields weak convergence of the flow.
We study the quantization of coupled Kahler-Einstein (CKE) metrics, namely we approximate CKE metrics by means of the canonical Bergman metrics, so called the ``balanced metrics. We prove the existence and weak convergence of balanced metrics for the
negative first Chern class, while for the positive first Chern class, we introduce some algebro-geometric obstruction which interpolates between the Donaldson-Futaki invariant and Chow weight. Then we show the existence and weak convergence of balanced metrics on CKE manifolds under the vanishing of this obstruction. Moreover, restricted to the case when the automorphism group is discrete, we also discuss approximate solutions and a gradient flow method towards the smooth convergence.
In this paper, we introduce the coupled Ricci iteration, a dynamical system related to the Ricci operator and twisted Kahler-Einstein metrics as an approach to the study of coupled Kahler-Einstein (CKE) metrics. For negative first Chern class, we pro
ve the smooth convergence of the iteration. For positive first Chern class, we also provide a notion of coercivity of the Ding functional, and show its equivalence to existence of CKE metrics. As an application, we prove the smooth convergence of the iteration on CKE Fano manifolds assuming that the automorphism group is discrete.
We prove a uniform diameter bound for long time solutions of the normalized Kahler-Ricci flow on an $n$-dimensional projective manifold $X$ with semi-ample canonical bundle under the assumption that the Ricci curvature is uniformly bounded for all ti
me in a fixed domain containing a fibre of $X$ over its canonical model $X_{can}$. This assumption on the Ricci curvature always holds when the Kodaira dimension of $X$ is $n$, $n-1$ or when the general fibre of $X$ over its canonical model is a complex torus. In particular, the normalized Kahler-Ricci flow converges in Gromov-Hausdorff topolopy to its canonical model when $X$ has Kodaira dimension $1$ with $K_X$ being semi-ample and the general fibre of $X$ over its canonical model being a complex torus. We also prove the Gromov-Hausdorff limit of collapsing Ricci-flat Kahler metrics on a holomorphically fibred Calabi-Yau manifold is unique and is homeomorphic to the metric completion of the corresponding twisted Kahler-Einstein metric on the regular part of its base.
Cristiano Spotti
,Song Sun
,Chengjian Yao
.
(2014)
.
"Existence and deformations of Kahler-Einstein metrics on smoothable Q-Fano varieties"
.
Chengjian Yao
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