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Let $G$ be a connected, complex reductive Lie group and $X$ a $\mathbb Q$-Fano $G$-spherical variety. In this paper we compute the weighed non-Archimedean functionals of a $G$-equivariant normal test configurations of $X$ via combinatory…

Differential Geometry · Mathematics 2022-11-08 Yan Li , ZhenYe Li , Feng Wang

We show that certain Galois covers of K-semistable Fano varieties are K-stable. We use this to give some new examples of Fano manifolds admitting K\"ahler-Einstein metrics, including hypersurfaces, double solids and threefolds.

Algebraic Geometry · Mathematics 2018-05-16 Ruadhaí Dervan

We give a survey of the recent progress on the study of K-stability of Fano varieties by an algebro-geometric approach.

Algebraic Geometry · Mathematics 2020-11-23 Chenyang Xu

We introduce a notion of K-stability for adjoint foliated structures via test configurations and the foliated Donaldson-Futaki invariant. We prove reduction to special test configurations for adjoint Fano foliated structures by showing that…

Algebraic Geometry · Mathematics 2026-05-22 Theodoros Stylianos Papazachariou

In this article we introduce a family of valuative invariants defined in terms of the $p$-th moment of the expected vanishing order. These invariants lie between $\alpha$ and $\delta$-invariants. They vary continuously in the big cone and…

Algebraic Geometry · Mathematics 2021-08-03 Kewei Zhang

We generalize the definition of alpha invariant to arbitrary codimension. We also give a lower bound of these alpha invariants for K-semistable Q-Fano varieties and show that we can characterize projective spaces among all K-semistable Fano…

Algebraic Geometry · Mathematics 2020-01-28 Ziwen Zhu

It is shown that any, possibly singular, Fano variety X admitting a Kahler-Einstein metric is K-polystable, thus confirming one direction of the Yau-Tian-Donaldson conjecture in the setting of Q-Fano varieties equipped with their…

Differential Geometry · Mathematics 2015-06-10 Robert J. Berman

To any projective pair $(X,B)$ equipped with an ample $\mathbb{Q}$-line bundle $L$ (or even any ample numerical class), we attach a new invariant $\beta(\mu)\in\mathbb{R}$, defined on convex combinations $\mu$ of divisorial valuations on…

Algebraic Geometry · Mathematics 2023-08-31 Sebastien Boucksom , Mattias Jonsson

We prove that for every $\epsilon>0$, there is a birationally super-rigid Fano variety $X$ such that $\frac{1}{2}\leqslant\alpha(X)\leqslant \frac{1}{2}+\epsilon$. Also we show that for every $\epsilon>0$, there is a Fano variety $X$ and a…

Algebraic Geometry · Mathematics 2023-04-25 Ivan Cheltsov , Arman Sarikyan , Ziquan Zhuang

Let $X$ be a Fano type variety and $(X,\Delta)$ be a log Calabi-Yau pair with $\Delta$ a Weil divisor. If $(X,\Delta)$ admits a polarized endomorphism, then we show that $(X,\Delta)$ is a finite quotient of a toric pair. Along the way, we…

Algebraic Geometry · Mathematics 2024-03-14 Joaquín Moraga , José Ignacio Yáñez , Wern Yeong

We define the relative stability threshold of a family of Fano varieties over a DVR and show that it is computed by a divisorial valuation. In the case when the special fiber is K-unstable, but the generic fiber is K-semistable, we use the…

Algebraic Geometry · Mathematics 2025-10-08 Harold Blum , Yuchen Liu , Chenyang Xu , Ziquan Zhuang

Let X be a normal complex projective variety with at worst klt singularities, and L a big line bundle on X. We use valuations to study the log canonical threshold of L, as well as another invariant, the stability threshold. The latter…

Algebraic Geometry · Mathematics 2020-02-11 Harold Blum , Mattias Jonsson

We prove the following result: if a $\mathbb{Q}$-Fano variety is uniformly K-stable, then it admits a K\"{a}hler-Einstein metric. We achieve this by modifying Berman-Boucksom-Jonsson's strategy with appropriate perturbative arguments and…

Differential Geometry · Mathematics 2021-03-30 Chi Li , Gang Tian , Feng Wang

Let $X$ be a nonsingular complex projective toric variety. We address the question of semi-stability as well as stability for the tangent bundle $T{X}$. In particular, a complete answer is given when $X$ is a Fano toric variety of dimension…

Algebraic Geometry · Mathematics 2021-12-17 Indranil Biswas , Arijit Dey , Ozhan Genc , Mainak Poddar

In this note, we discuss a number of open problems in K-stability theory.

Algebraic Geometry · Mathematics 2026-01-23 Chenyang Xu , Ziquan Zhuang

Let $(X, \Delta)$ be a log Fano pair with standard coefficients endowed with a singular K\"ahler--Einstein metric. We show that the adapted tangent sheaf $\mathcal{T}_{X, \Delta, f}$ and the adapted canonical extension $\mathcal{E}_{X,…

Differential Geometry · Mathematics 2026-01-28 Louis Dailly

We show that the anti-canonical volume of an $n$-dimensional K\"ahler-Einstein $\mathbb{Q}$-Fano variety is bounded from above by certain invariants of the local singularities, namely $\mathrm{lct}^n\cdot\mathrm{mult}$ for ideals and the…

Algebraic Geometry · Mathematics 2019-02-20 Yuchen Liu

We prove that the stability condition for Fano manifolds defined by Saito-Takahashi, given in terms of the sum of the Ding invariant and the Chow weight, is equivalent to the existence of anticanonically balanced metrics. Combined with the…

Differential Geometry · Mathematics 2024-01-18 Yoshinori Hashimoto

We study Fano varieties endowed with a faithful action of a symmetric group, as well as analogous results for Calabi--Yau varieties, and log terminal singularities. We show the existence of a constant $m(n)$, so that every symmetric group…

Algebraic Geometry · Mathematics 2025-02-05 Louis Esser , Lena Ji , Joaquín Moraga

We present some applications of the deformation theory of toric Fano varieties to K-(semi/poly)stability of Fano varieties. First, we present two examples of K-polystable toric Fano 3-fold with obstructed deformations. In one case, the…

Algebraic Geometry · Mathematics 2021-09-02 Anne-Sophie Kaloghiros , Andrea Petracci