English
Related papers

Related papers: Higher Codimensional Alpha Invariants and Characte…

200 papers

In this short note, we show that K-semistable Fano manifolds with the smallest alpha invariant are projective spaces. Singular cases are also investigated.

Algebraic Geometry · Mathematics 2017-11-27 Chen Jiang

We compute global log canonical thresholds, or equivalently alpha invariants, of birationally rigid orbifold Fano threefolds embedded in weighted projective spaces as codimension two or three. As an important application, we prove that most…

Algebraic Geometry · Mathematics 2016-04-04 In-Kyun Kim , Takuzo Okada , Joonyeong Won

We show that fixed dimensional klt weak Fano pairs with alpha-invariants and volumes bounded away from $0$ and the coefficients of the boundaries belong to the set of hyperstandard multiplicities $\Phi(\mathscr{R})$ associated to a fixed…

Algebraic Geometry · Mathematics 2018-10-24 Weichung Chen

A result of Kento Fujita says that the volume of a K\"ahler-Einstein Fano manifold is bounded from above by the volume of the projective space. In this short note we establish quantized versions of Fujita's result.

Algebraic Geometry · Mathematics 2025-04-15 Kewei Zhang

The representations of dimension vector $\alpha$ of the quiver Q can be parametrised by a vector space $R(Q,\alpha)$ on which an algebraic group $\Gl(\alpha)$ acts so that the set of orbits is bijective with the set of isomorphism classes…

Rings and Algebras · Mathematics 2007-05-23 Aidan Schofield , Michel Van den Bergh

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 show that the complex projective space has maximal degree (volume) among all n-dimensional Kahler-Einstein Fano manifolds admitting a holomorphic C^*-action with a finite number of fixed points. The toric version of this result,…

Differential Geometry · Mathematics 2012-04-06 Robert J. Berman , Bo Berndtsson

For an embedded Fano manifold $X$, we introduce a new invariant $S_X$ related to the dimension of covering linear spaces. The aim of this paper is to classify Fano manifolds $X$ which have large $S_X$.

Algebraic Geometry · Mathematics 2017-06-20 Taku Suzuki

In this short note we show the unboundedness of the dimension of the K-moduli space of $n$-dimensional Fano varieties, and that the dimension of the stack can also be unbounded while, simultaneously, the dimension of the corresponding…

Algebraic Geometry · Mathematics 2021-01-15 Jesus Martinez-Garcia , Cristiano Spotti

We give a purely algebro-geometric proof that if the alpha-invariant of a Q-Fano variety X is greater than dim X/(dim X+1), then (X,O(-K_X)) is K-stable. The key of our proof is a relation among the Seshadri constants, the alpha-invariant…

Algebraic Geometry · Mathematics 2012-08-10 Yuji Odaka , Yuji Sano

We study Q-Fano threefolds of large Fano index. In particular, we prove that the maximum of Fano index is attained for the weighted projective space P(3,4,5,7).

Algebraic Geometry · Mathematics 2011-01-18 Yuri Prokhorov

We prove that every birationally superrigid Fano variety whose alpha invariant is greater than (resp. no smaller than) $\frac{1}{2}$ is K-stable (resp. K-semistable). We also prove that the alpha invariant of a birationally superrigid Fano…

Algebraic Geometry · Mathematics 2019-08-15 Charlie Stibitz , Ziquan Zhuang

We define the characteristic numbers of a holomorphic k-distribution of any dimension on $mathbb P^n$ and obtain relations between these numbers and the characteristic numbers of an invariant subvariety. As an application we bound the…

Algebraic Geometry · Mathematics 2011-07-11 Maycol Falla Luza , Thiago Fassarella

For a variety $X$, a big $\mathbb{Q}$-divisor $L$ and a closed connected subgroup $G \subset \mathrm{Aut}(X, L)$ we define a $G$-invariant version of the $\delta$-threshold. We prove that for a Fano variety $(X, -K_X)$ and a connected…

Algebraic Geometry · Mathematics 2020-08-27 Aleksei Golota

This work explores the space of foliations on projective spaces over algebraically closed fields of positive characteristic, with a particular focus on the codimension one case. It describes how the irreducible components of these spaces…

Algebraic Geometry · Mathematics 2025-04-18 Wodson Mendson , Jorge Vitório Pereira

Fano varieties are 'atomic pieces' of algebraic varieties, the shapes that can be defined by polynomial equations. We describe the role of computation and database methods in the construction and classification of Fano varieties, with an…

Algebraic Geometry · Mathematics 2022-11-21 Gavin Brown , Tom Coates , Alessio Corti , Tom Ducat , Liana Heuberger , Alexander Kasprzyk

We show that $\mathbb{Q}$-Fano varieties of fixed dimension with anti-canonical degrees and alpha-invariants bounded from below form a bounded family. As a corollary, K-semistable $\mathbb{Q}$-Fano varieties of fixed dimension with…

Algebraic Geometry · Mathematics 2021-01-22 Chen Jiang

We show that any $n$-dimensional Fano manifold $X$ with $\alpha(X)=n/(n+1)$ and $n\geq 2$ is K-stable, where $\alpha(X)$ is the alpha invariant of $X$ introduced by Tian. In particular, any such $X$ admits K\"ahler-Einstein metrics and the…

Algebraic Geometry · Mathematics 2016-06-28 Kento Fujita

The global holomorphic \alpha-invariant introduced by Tian is closely related with the study in the existence of Kahler-Einstein metric. We apply the result of Tian, Lu and Zelditch on polarized Kahler metrics to approximate…

Differential Geometry · Mathematics 2007-05-23 Jian Song

In an earlier work, we investigated some consequences of the existence of a K\"ahler metric of negative holomorphic sectional curvature on a projective manifold. In the present work, we extend our results to the case of semi-negative (i.e.,…

Algebraic Geometry · Mathematics 2015-06-10 Gordon Heier , Steven S. Y. Lu , Bun Wong
‹ Prev 1 2 3 10 Next ›