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Related papers: On the global log canonical threshold of Fano comp…

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It is proved that the global log canonical threshold of a Zariski general Fano complete intersection of index 1 and codimension $k$ in ${\mathbb P}^{M+k}$ is equal to one, if $M\geqslant 2k+3$ and the maximum of the degrees of defining…

Algebraic Geometry · Mathematics 2017-04-04 Aleksandr V. Pukhlikov

We study log canonical thresholds on quartic threefolds, quintic fourfolds, and double spaces. As an application, we show that they have a Kaehler-Einstein metric if they are general.

Algebraic Geometry · Mathematics 2015-01-05 Ivan Cheltsov , Jihun Park , Joonyeong Won

We relate the global log canonical threshold of a variety with torus action to the global log canonical threshold of its quotient. We apply this to certain Fano varieties and use Tian's criterion to prove the existence of Kahler-Einstein…

Algebraic Geometry · Mathematics 2013-08-13 Hendrik Süß

We compute global log canonical thresholds of certain birationally bi-rigid Fano 3-folds embedded in weighted projective spaces as complete intersections of codimension 2 and prove that they admit an orbifold K\"{a}hler-Einstein metric and…

Algebraic Geometry · Mathematics 2019-03-19 In-Kyun Kim , Takuzo Okada , Joonyeong Won

In this paper we show that the global (log) canonical threshold of $d$-sheeted covers of the $M$-dimensional projective space of index 1, where $d\geqslant 4$, is equal to one for almost all families (except for a finite set). The varieties…

Algebraic Geometry · Mathematics 2019-06-28 Aleksandr V. Pukhlikov

We prove that a Fano complete intersection of codimension $k$ and index 1 in the complex projective space ${\mathbb P}^{M+k}$ for $k\geqslant 20$ and $M\geqslant 8k\log k$ with at most multi-quadratic singularities is birationally…

Algebraic Geometry · Mathematics 2020-01-08 Daniel Evans , Aleksandr Pukhlikov

We study global log canonical thresholds on anticanonically embedded quasismooth weighted Fano threefold hypersurfaces having terminal quotient singularities to prove the existence of a Kahler-Einstein metric on most of them, and to produce…

Algebraic Geometry · Mathematics 2007-06-18 Ivan Cheltsov

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 provide enumerative formulas for the degrees of varieties parameterizing hypersurfaces and complete intersections which contain pro-jective subspaces and conics. Besides, we find all cases where the Fano scheme of the general complete…

Algebraic Geometry · Mathematics 2019-04-18 Ciro Ciliberto , M Zaidenberg

We compute global log canonical thresholds of some smooth Fano threefolds.

Algebraic Geometry · Mathematics 2009-02-08 Ivan Cheltsov , Constantin Shramov

In this paper, we study the explicit geometry of threefolds, in particular, Fano varieties. We find an explicitly computable positive integer $N$, such that all but a bounded family of Fano threefolds have $N$-complements. This result has…

Algebraic Geometry · Mathematics 2023-11-14 Caucher Birkar , Jihao Liu

We propose new types of canonical metrics on K\"ahler manifolds, called coupled K\"ahler-Einstein metrics, generalizing K\"ahler-Einstein metrics. We prove existence and uniqueness results in the cases when the canonical bundle is ample and…

Differential Geometry · Mathematics 2017-03-16 Jakob Hultgren , David Witt Nyström

We study log canonical thresholds (also called global log canonical threshold or $\alpha$-invariant) of $\mathbb{R}$-linear systems. We prove existence of positive lower bounds in different settings, in particular, proving a conjecture of…

Algebraic Geometry · Mathematics 2020-12-02 Caucher Birkar

It was conjectured by Tian that the global log canonical threshold (known as the $\alpha$-invariant) is equal to the level $k$ log canonical threshold (known as the $\alpha_k$-invariant) for all sufficiently large $k$. A weaker folklore…

Algebraic Geometry · Mathematics 2024-12-04 Chenzi Jin

Let $S$ be a minimal surface of general type with $p_g(S)=2$ and $K^2_S=1$, so called by a minimal $(1,2)$-surface. Then we obtain that the global log canonical threshold of the surface $S$ via $K_S$ is greater than equal to $\frac{1}{2}$.…

Algebraic Geometry · Mathematics 2018-05-07 In-Kyun Kim , YongJoo Shin , Joonyeong Won

We study Gorenstein almost Fano threefolds X with canonical singularities and pseudoindex > 1. We show that the maximal Picard number of X is 10 in general, 3 if X is Fano, and 8 if X is toric. Moreover, we characterize the boundary cases.…

Algebraic Geometry · Mathematics 2007-05-23 C. Casagrande , P. Jahnke , I. Radloff

We investigate the variation of log canonical thresholds in (graded) linear systems. For toric log Fano varieties, we give a sharp lower bound for log canonical thresholds of the anticanonical members in terms of the global minimal log…

Algebraic Geometry · Mathematics 2014-11-12 Florin Ambro

We prove a more general and precise version of the Noether-Fano inequalities for birational maps between Mori fiber spaces. This is applied to give descriptions of global canonical thresholds on Fano varieties of Picard number one.

Algebraic Geometry · Mathematics 2021-03-03 Charlie Stibitz

We generalize Givental's Theorem for complete intersections in smooth toric varieties in the Fano case. In particular, we find Gromov--Witten invariants of Fano varieties of dimension $\geq 3$, which are complete intersections in weighted…

Algebraic Geometry · Mathematics 2018-08-07 Victor Przyjalkowski

We prove that every smooth Fano complete intersection of index $1$ and codimension $r$ in $\mathbb{P}^{n+r}$ is birationally superrigid and K-stable if $n\ge 10r$. We also propose a generalization of Tian's criterion of K-stability and, as…

Algebraic Geometry · Mathematics 2021-02-22 Ziquan Zhuang
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