English
Related papers

Related papers: A question about generalized nonvanishing

200 papers

For smooth projective 3-folds of general type, we prove that the relative canonical stability $\mu_s(3)\leq 8$. This is induced from our improved result of Koll\'ar: the m-canonical map of a smooth projective 3-fold of general type is…

Algebraic Geometry · Mathematics 2007-05-23 Meng Chen

Let $X$ be a normal projective variety with only klt singularities, and $L_X$ a strictly nef $\mathbb{Q}$-divisor on $X$. In this paper, we study the singular version of Serrano's conjecture, i.e., the ampleness of $K_X+t L_X$ for…

Algebraic Geometry · Mathematics 2024-08-06 Juanyong Wang , Guolei Zhong

We prove that a holomorphic line bundle on a projective manifold is pseudo-effective if and only if its degree on any member of a covering family of curves is non-negative. This is a consequence of a duality statement between the cone of…

Algebraic Geometry · Mathematics 2007-05-23 Sébastien Boucksom , Jean-Pierre Demailly , Mihai Paun , Thomas Peternell

We prove that the non-nef locus and the restricted base locus of a pseudoeffective divisor coincide on KLT pairs. We also extend to KLT pairs F. Russo's characterization of nef and abundant divisors by means of asymptotic multiplier ideals.

Algebraic Geometry · Mathematics 2012-10-19 Salvatore Cacciola , Lorenzo Di Biagio

We show the termination of any log-minimal model program for a pair $(X,\Delta)$ of a symplectic manifold $X$ and an effective $\mathbb R$-divisor $\Delta$.

Algebraic Geometry · Mathematics 2014-05-23 Christian Lehn , Gianluca Pacienza

Let $S$ be a rational surface with $\dim|-K_S|\ge 1$ and let $\pi: X\rightarrow S$ be a ramified cyclic covering from a nonruled smooth surface $X$. We show that for any integer $k\ge 3$ and ample divisor $A$ on $S$, the adjoint divisor…

Algebraic Geometry · Mathematics 2019-04-10 Lei Song

If the log canonical divisor on a projective variety with only Kawamata log terminal singularities is numerically equivalent to some semi-ample $\mathbf{Q}$-divisor, then it is semi-ample.

Algebraic Geometry · Mathematics 2011-11-07 Shigetaka Fukuda

We prove that if $(X,\Delta)$ is a threefold pair with mild singularities such that ${-}(K_X+\Delta)$ is nef, then the numerical class of ${-}(K_X+\Delta)$ is effective.

Algebraic Geometry · Mathematics 2023-12-14 Vladimir Lazić , Shin-ichi Matsumura , Thomas Peternell , Nikolaos Tsakanikas , Zhixin Xie

Let $X$ be a smooth projective variety. The Iitaka dimension of a divisor $D$ is an important invariant, but it does not only depend on the numerical class of $D$. However, there are several definitions of ``numerical Iitaka dimension'',…

Algebraic Geometry · Mathematics 2019-04-25 John Lesieutre

Motivated by the classical Theorems of Picard and Siegel and their generalizations, we define the notion of an {\it essentially large} effective divisor and derive some of its geometric and arithmetic consequences. We then prove that on a…

Algebraic Geometry · Mathematics 2010-06-08 Gordon Heier , Min Ru

In this paper we study the positivity of the cotangent bundle of projective manifolds. We conjecture that the cotangent bundle is pseudoeffective if and only the manifold has non-zero symmetric differentials. We confirm this conjecture for…

Algebraic Geometry · Mathematics 2020-06-11 Andreas Höring , Thomas Peternell

We show that Kov\'acs' result on the cone of curves of a K3 surface generalizes to any projective irreducible holomorphic symplectic manifold $X$. In particular, we show that if $\rho(X)\geq 3$, the pseudo-effective cone…

Algebraic Geometry · Mathematics 2024-12-30 Francesco Antonio Denisi

We introduce the notion of potentially klt pairs for normal projective varieties with pseudoeffective anticanonical divisor. The potentially non-klt locus is a subset of $X$ which is birationally transformed precisely into the non-klt locus…

Algebraic Geometry · Mathematics 2016-06-10 Sung Rak Choi , Jinhyung Park

Let X be a smooth complex projective variety of dimension 4 and let L be an ample line bundle on X. In this paper, we study a natural number m such that h^{0}(m(K_{X}+L))>0 for any polarized 4-folds (X,L) with \kappa(K_{X}+L)\geq 0.

Algebraic Geometry · Mathematics 2010-10-25 Yoshiaki Fukuma

The following generalization of a result of S. Nemirovski is proved: if $X$ is either a projective or a Stein manifold and $K\subset X$ is a compact sublevel set of a strictly plurisubharmonic function $\varphi$ defined in a neighborhood of…

Complex Variables · Mathematics 2024-11-01 Blake J. Boudreaux , Purvi Gupta , Rasul Shafikov

By applying the Chen-Jiang decomposition, we prove that the non-vanishing conjecture holds for an lc pair \((X, \Delta)\), where \(X\) is an irregular variety, provided it holds for lower-dimensional varieties. In the second part, we extend…

Algebraic Geometry · Mathematics 2025-01-09 Houari Benammar Ammar

In this article we show that if $(X, \Delta)$ is a log canonical compact K\"ahler $3$-fold such that $K_X+\Delta$ is nef and the numerical dimension $\nu(K_X+\Delta)\neq 2$, then $K_X+\Delta$ is semi-ample.

Algebraic Geometry · Mathematics 2023-02-22 Omprokash Das , Wenhao Ou

Let $\mathbb{K}$ be an algebraically closed field of characteristic $p>5$. We show the existence of minimal models for pseudo-effective NQC lc generalized pairs in dimension three over $\mathbb{K}$. As a consequence, we prove the…

Algebraic Geometry · Mathematics 2024-11-21 Tianle Yang , Zelin Ye , Zhiyao Zhang

In this paper we prove that given a pair $(X,D)$ of a threefold $X$ and a boundary divisor $D$ with mild singularities, if $(K_X+D)$ is movable, then the orbifold second Chern class $c_2$ of $(X,D)$ is pseudo-effective. This generalizes the…

Algebraic Geometry · Mathematics 2022-08-04 Erwan Rousseau , Behrouz Taji

We study the complex-analytic geometry of semi-positive holomorphic line bundles on compact K\"ahler manifolds. In one of our main results, for a $\mathbb{Q}$-effective line bundle satisfying a natural torsion-type assumption, we show the…

Complex Variables · Mathematics 2026-01-23 Takayuki Koike