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Related papers: Dynamical Iitaka theory on Fano contractions

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We consider some conditions under which a smooth projective variety X is actually the projective space. We also extend to the case of positive characteristic some results in the theory of vector bundle adjunction. We use methods and…

Algebraic Geometry · Mathematics 2007-05-23 Marco Andreatta

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 develop an intersection theory for a singular hemitian line bundle with positive curvature current on a smooth projective variety and irreducible curves on the variety. And we prove the existence of a natural rational fibration structure…

Algebraic Geometry · Mathematics 2007-05-23 Hajime Tsuji

In this note, we investigate fibre space structures of a projective irreducible symplectic manifold. We prove that an 2n-dimensional projective irreducible symplectic manifold admits only an n-dimensional fibration over a Fano variety which…

alg-geom · Mathematics 2016-08-30 Daisuke Matsushita

Given a semistable fibration $f\colon X\to B$ we introduce a correspondence between foliations $\mathcal{F}$ on $X$ and local systems $\mathbb{L}$ on $B$. Building up on this correspondence we find conditions that give maximal rationally…

Algebraic Geometry · Mathematics 2022-05-31 Luca Rizzi , Francesco Zucconi

We develop the quadratic technique of proving birational rigidity of Fano-Mori fibre spaces over a higher-dimensional base. As an application, we prove birational rigidity of generic fibrations into Fano double spaces of dimension…

Algebraic Geometry · Mathematics 2017-12-15 Aleksandr V. Pukhlikov

Let $f\colon X\rightarrow X$ be a surjective endomorphism of a normal projective variety defined over a number field. The dynamics of $f$ may be studied through the dynamics of the linear action $f^*\colon Pic(X)_\mathbb{R}\rightarrow…

Algebraic Geometry · Mathematics 2020-12-03 Brett Nasserden

Let X be a projective variety with terminal singularities and let L be an ample Cartier divisor on X. We prove that if f is a birational contraction associated to an extremal ray $ R \subset \bar {NE(X)}$ such that R.(K_X+(n-2)L)<0, then f…

Algebraic Geometry · Mathematics 2018-05-16 Marco Andreatta , Luca Tasin

By applying the positivity theorem of direct images and a pluricanonical version of the structure theorem on the cohomology jumping loci \`a la Green-Lazarsfeld-Simpson, we show that the klt K\"ahler version of the Iitaka conjecture…

Algebraic Geometry · Mathematics 2019-07-17 Juanyong Wang

We show that fiberwise stable vector bundles are preserved by relative Fourier-Mukai transforms between elliptic threefolds with relative Picard number one. Using these bundles we define new invariants of elliptic fibrations, and we relate…

Algebraic Geometry · Mathematics 2007-05-23 Andrei Caldararu

In this paper we prove birational rigidity of large classes of Fano-Mori fibre spaces over a base of arbitrary dimension, bounded from above by a constant that depends on the dimension of the fibre only. In order to do that, we first show…

Algebraic Geometry · Mathematics 2015-09-30 Aleksandr V. Pukhlikov

We discuss the flatness property of some fiber type contractions of complex smooth projective varieties of arbitrary dimensions. We relate the flatness of some morphisms having one-dimensional fibers with their conic bundles structures,…

Algebraic Geometry · Mathematics 2019-06-27 Eleonora Anna Romano

We give the first examples of flat fiber type contractions of Fano manifolds onto varieties that are not weak Fano, and we prove that these morphisms are Fano conic bundles. We also review some known results about the interaction between…

Algebraic Geometry · Mathematics 2017-03-09 Eleonora Anna Romano

We give an account, in terms of fibered categories and their fibrewise duals, of aspects of the theory of bundle functors and star-bundle functors in differential geometry.

Category Theory · Mathematics 2015-05-12 Anders Kock

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

It is conjectured that the base varieties of the Iitaka fibrations are bounded when the Iitaka volumes are bounded above. We confirm this conjecture for Iitaka $\epsilon$-lc Fano type fibrations.

Algebraic Geometry · Mathematics 2023-01-26 Zhan Li

Let $f:X\to X$ be a non-isomorphic (i.e., $\text{deg } f>1$) surjective endomorphism of a smooth projective threefold $X$. We prove that any birational minimal model program becomes $f$-equivariant after iteration, provided that $f$ is…

Algebraic Geometry · Mathematics 2023-09-14 Sheng Meng , De-Qi Zhang

We construct smooth varieties admitting small contractions from arbitrary smooth projective varieties. This construction generalizes Kawamata's four-dimensional example. We also give sufficient conditions for divisors on these varieties to…

Algebraic Geometry · Mathematics 2026-01-21 Yuto Masamura , Tomoki Yoshida

In this article, we investigate Serrano's conjecture for strictly nef divisors on projective bundles over higher dimensional smooth projective varieties.

Algebraic Geometry · Mathematics 2024-05-10 Snehajit Misra

Let X ->Y be a Zariski locally trivial fibration of smooth complex projective varieties, with fiber F. We give a structure theorem for the derived category of X provided both F and Z have a full strongly exceptional collection of line…

Algebraic Geometry · Mathematics 2011-02-10 L. Costa , S. Di Rocco , R. M. Miró-Roig