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We study global log canonical thresholds of del Pezzo surfaces.

Algebraic Geometry · Mathematics 2008-04-29 Ivan Cheltsov

We classify all the effective anticanonical divisors on weak del Pezzo surfaces. Through this classification we obtain the smallest number among the log canonical thresholds of effective anticanonical divisors on a given Gorenstein…

Algebraic Geometry · Mathematics 2015-01-08 Jihun Park , Joonyeong Won

The global log canonical threshold (or Tian's alpha-invariant) plays an important role in the geometry of Fano varieties. Tian showed that Fano manifolds with big alpha-invariant can be equipped with a Kahler-Einstein metric. In recent…

Algebraic Geometry · Mathematics 2013-09-06 Jesus Martinez-Garcia

The global log canonical threshold of each non-singular complex del Pezzo surface was computed by Cheltsov. The proof used Koll\'ar-Shokurov's connectedness principle and other results relying on vanishing theorems of Kodaira type, not…

Algebraic Geometry · Mathematics 2016-07-12 Jesus Martinez-Garcia

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 consider two classes of non-toric log del Pezzo $\mathbb{C}^*$-surfaces: on the one side the 1/3-log canonical ones and on the other side those of Picard number one and Gorenstein index at most 65. In each of the two classes we figure…

Algebraic Geometry · Mathematics 2023-06-07 Daniel Hättig , Jürgen Hausen , Hendrik Süß

The log canonical thresholds of irreducible quasi-ordinary hypersurface singularities are computed, using an explicit list of pole candidates for the motivic zeta function found by the last two authors.

Algebraic Geometry · Mathematics 2011-05-16 Nero Budur , Pedro D. González-Pérez , Manuel González Villa

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 compute global log canonical thresholds of a large class of quasismooth well-formed del Pezzo weighted hypersurfaces in $\mathbb{P}(a_{1},a_{2},a_{3},a_{4})$. As a corollary we obtain the existence of orbifold K\"ahler--Einstein metrics…

Algebraic Geometry · Mathematics 2009-04-06 Ivan Cheltsov , Jihun Park , Constantin Shramov

We use intersection theory, degeneration techniques and jet schemes to study log canonical thresholds. Our first result gives a lower bound for the log canonical threshold of a pair in terms of the log canonical threshold of the image by a…

Algebraic Geometry · Mathematics 2007-05-23 Tommaso de Fernex , Lawrence Ein , Mircea Mustata

We prove that the first gap of $\mathbb R$-complementary thresholds of surfaces is $\frac{1}{13}$. More precisely, the largest $\mathbb R$-complementary threshold for surfaces that is strictly less than $1$ is $\frac{12}{13}$. This result…

Algebraic Geometry · Mathematics 2023-05-31 Jihao Liu , V. V. Shokurov

In this paper we give an upper bound for the Picard number of the rational surfaces which resolve minimally the singularities of toric log Del Pezzo surfaces of given index $\ell$. This upper bound turns out to be a quadratic polynomial in…

Algebraic Geometry · Mathematics 2010-02-14 Dimitrios I. Dais , Benjamin Nill

We show that if a divisor centered over a point on a smooth surface computes a minimal log discrepancy, then the divisor also computes a log canonical threshold. To prove the result, we study the asymptotic log canonical threshold of the…

Algebraic Geometry · Mathematics 2017-06-08 Harold Blum

We prove an upper bound on the log canonical threshold of a hypersurface that satisfies a certain power condition and use it to prove several generalizations of Igusa's conjecture on exponential sums, with the log-canonical threshold in the…

Number Theory · Mathematics 2019-03-20 Raf Cluckers , Mircea Mustaţǎ , Kien Huu Nguyen

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

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

Motivated by the study of Fano type varieties we define a new class of log pairs that we call asymptotically log Fano varieties and strongly asymptotically log Fano varieties. We study their properties in dimension two under an additional…

Algebraic Geometry · Mathematics 2015-09-17 Ivan A. Cheltsov , Yanir A. Rubinstein

We give an optimal upper bound for the anti-canonical volume of an $\epsilon$-lc weak log del Pezzo surface. Moreover, we consider the relation between the bound of the volume and the Picard number of the minimal resolution of the surface.…

Algebraic Geometry · Mathematics 2014-05-29 Chen Jiang

In this paper we characterize two-dimensional semi-log canonical hypersurfaces in arbitrary characteristic from the viewpoint of the initial term of the defining equation. As an application, we prove a conjecture about a uniform bound of…

Algebraic Geometry · Mathematics 2020-01-03 Kohsuke Shibata

In this paper we study the problem of existence of orbifold Kaehler-Einstein metrics on del Pezzo surfaces of degree 1 with Du Val singular points. Moreover we compute global log canonical thresholds of del Pezzo surfaces of degree 1 with…

Algebraic Geometry · Mathematics 2009-04-19 Dimitra Kosta
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