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Related papers: On the uniformity of the Iitaka fibration

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For every smooth complex projective variety $W$ of dimension $d$ and nonnegative Kodaira dimension, we show the existence of a universal constant $m$ depending only on $d$ and two natural invariants of the very general fibres of an Iitaka…

Algebraic Geometry · Mathematics 2018-09-24 Caucher Birkar , De-Qi Zhang

In this paper we will prove a uniformity result for the Iitaka fibration $f:X \rightarrow Y$, provided that the generic fiber has a good minimal model and the variation of $f$ is zero or that $\kappa(X)=\rm{dim}(X)-1$.

Algebraic Geometry · Mathematics 2012-03-05 Xiaodong Jiang

We prove that for any smooth complex projective threefold of Kodaira dimension one, the $m$-th pluricanonical map is birational to the Iitaka fibration for every $m\geq5868$ and divisible by $12$.

Algebraic Geometry · Mathematics 2021-09-13 Hsin-Ku Chen

A vector bundle on a smooth projective variety, if it is generically generated by global sections, yields a rational map to a Grassmannian, called Kodaira map. We investigate the asymptotic behaviour of the Kodaira maps for the symmetric…

Algebraic Geometry · Mathematics 2017-01-27 Ernesto C. Mistretta , Stefano Urbinati

We show that the M-canonical map of an n-dimensional complex projective manifold X of Kodaira dimension two is birational to an Iitaka fibration for a computable positive integer M. M depends on the index b of a general fibre F of the…

Algebraic Geometry · Mathematics 2018-06-20 Eckart Viehweg , De-Qi Zhang

We prove the invariance of plurigenera under smooth projective deformations of varieties with nonnegative Kodaira dimensions.

Algebraic Geometry · Mathematics 2016-09-07 Hajime Tsuji

Given a fibration over a perfect field of positive characteristic, we study an Iitaka-type inequality for the anticanonical divisors. We conclude that it holds when the source of the fibration is a threefold or when the target is a curve,…

Algebraic Geometry · Mathematics 2026-03-27 Marta Benozzo

We prove that there exists a universal constant $r_3$ such that if $X$ is a smooth projective threefold over $\mathbb{C}$ with non-negative Kodaira dimension, then the linear system $|r K_X|$ admits a fibration that is birational to the…

Algebraic Geometry · Mathematics 2007-09-13 Adam Ringler

Given a (meromorphic) fibration $f:X\to Y$ where $X$ and $Y$ are compact complex manifolds of dimensions $n$ and $m$, we define $L_f$ to be the invertible subsheaf of the sheaf of holomorphic $m$-forms of $X$ given by the saturation of…

Algebraic Geometry · Mathematics 2007-05-23 Steven S. Y. Lu

In this paper, we prove that for a fibration $f:X\to Z$ from a smooth projective 3-fold to a smooth projective curve, over an algebraically closed field $k$ with $\mathrm{char} k =p >5$, if the geometric generic fiber $X_{\overline\eta}$ is…

Algebraic Geometry · Mathematics 2018-06-26 Sho Ejiri , Lei Zhang

We give effective bounds for the uniformity of the Iitaka fibration. These bounds follow from an effective theorem on the birationality of some adjoint linear series. In particular we derive an effective version of the main theorem in [17].

Algebraic Geometry · Mathematics 2011-11-30 Gabriele Di Cerbo

In this paper, we establish a structure theorem for minimal projective klt varieties $X$ that satisfiy Miyaoka's equality $3c_2(X) = c_1(X)^2$. Specifically, we prove that the canonical divisor $K_X$ is semi-ample and that the Kodaira…

Algebraic Geometry · Mathematics 2025-10-23 Masataka Iwai , Shin-ichi Matsumura , Niklas Müller

We study the Iitaka-Kodaira dimension of nef relative anti-canonical divisors. As a consequence, we prove that given a complex projective variety with klt singularities, if the anti-canonical divisor is nef, then the dimension of a general…

Algebraic Geometry · Mathematics 2019-07-10 Sho Ejiri , Yoshinori Gongyo

We give several structure theorems for certain surjective endomorphisms on Mori fibre spaces, based on the dynamical Iitaka fibration of the ramification divisor. As an application, we prove the Kawaguchi-Silverman conjecture for projective…

Algebraic Geometry · Mathematics 2025-06-23 Sheng Meng , Long Wang , Tianle Yang

We show, using [14], that a smooth projective fibration f : X $\rightarrow$ Y between connected complex quasi-projective manifolds satisfies the equality $\kappa$(X) = $\kappa$(X y) + $\kappa$(Y) of Logarithmic Kodaira dimensions if its…

Algebraic Geometry · Mathematics 2023-03-09 Frederic Bruno Campana

We explore the relationship between fibrations arising naturally from a surjective morphism to an abelian variety. These fibrations encode geometric information about the morphism. Our study focuses on the interplay of these fibrations and…

Algebraic Geometry · Mathematics 2024-07-24 Fanjun Meng

We prove several results on the additivity of Kodaira dimension under smooth morphisms of smooth projective varieties.

Algebraic Geometry · Mathematics 2024-11-27 Mihnea Popa , Christian Schnell

We express the Kodaira-Iitaka dimension and the multiplicity of graded linear series in terms of the intersection theory of the plurisubharmonic envelope associated with the linear series, and obtain two refined versions of these formulas…

Complex Variables · Mathematics 2026-03-24 Siarhei Finski

Given a fibration $f: X \to Y$ with normal general fibre $X_y$, over a field of any characteristic, we establish the Iitaka-type inequality $\kappa(X,-K_X) \leq \kappa(X_y,-K_{X_y})+\kappa(Y,-K_Y)$ whenever the $\mathbb{Q}$-linear series…

Algebraic Geometry · Mathematics 2026-03-27 Marta Benozzo , Iacopo Brivio , Chi-Kang Chang

Let X be a smooth, projective variety over the field of complex numbers. Here we focus on a conjecture attributed to Shigefumi Mori, which claims that X is uniruled if and only if the Kodaira dimension of X is negative.

Algebraic Geometry · Mathematics 2025-05-20 Gilberto Bini
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