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Related papers: On foliations with nef anti-canonical bundle

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To any compact K\"ahler manifold $(X, \omega)$ one may associate a bundle of affine spaces $Z_X\rightarrow X$ called a \emph{canonical extension} of $X$. In this paper we prove that if the tangent bundle of $X$ is nef, then the total space…

Algebraic Geometry · Mathematics 2026-01-22 Niklas Müller

This article studies codimension one foliations on projective man-ifolds having a compact leaf (free of singularities). It explores the interplay between Ueda theory (order of flatness of the normal bundle) and the holo-nomy representation…

Classical Analysis and ODEs · Mathematics 2018-08-31 Benoît Claudon , Frank Loray , Jorge Pereira , Frédéric Touzet

As a special case of a conjecture by Schwede and Smith, we prove that a smooth complex projective threefold with nef anti-canonical divisor is weak Fano if it is of globally $F$-regular type.

Algebraic Geometry · Mathematics 2024-10-08 Paolo Cascini , Tatsuro Kawakami , Shunsuke Takagi

We aim to classify codimension 1 foliations $\mathscr{F}$ with canonical singularities and $\nu(K_{\mathscr{F}}) < 3$ on threefolds of general type. We prove a classification result for foliations satisfying these conditions and having…

Algebraic Geometry · Mathematics 2023-03-22 Aleksei Golota

In this article we prove new results on projective normality and normal presentation of adjunction bundle associated to an ample and globally generated line bundle on higher dimensional smooth projective varieties with nef canonical bundle.…

Algebraic Geometry · Mathematics 2019-09-10 Jayan Mukherjee , Debaditya Raychaudhury

Given a fibration $f$ between two projective manifolds $X$ and $Y$, we provide a sufficient condition such that the direct images $f_{\ast}(K_{X/Y}\otimes L\otimes\mathscr{I}(f,\|L\|))$ is nef, where $L$ is a holomorphic line bundle with…

Algebraic Geometry · Mathematics 2021-08-10 Jingcao Wu

We prove that the Albanese map of a smooth projective threefold, whose anticanonical bundle is nef, is a surjective submersion. We also investigate morphisms of threefolds to curves and surfaces whose relative anticanonical bundle are nef.

Algebraic Geometry · Mathematics 2007-05-23 Thomas Peternell , Fernando Serrano

Let $f:M\to M$ be a dynamically coherent partially hyperbolic diffeomorphism whose center foliation has all its leaves compact. We prove that if the unstable bundle of $f$ is one-dimensional, then the volume of center leaves must be bounded…

Dynamical Systems · Mathematics 2019-01-01 Verónica De Martino , Santiago Martinchich

Let $X$ be a general conic bundle over the projective plane with branch curve of degree at least 19. We prove that there is no normal projective variety $Y$ that is birational to $X$ and such that some multiple of its anticanonical divisor…

Algebraic Geometry · Mathematics 2023-06-22 János Kollár

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

In this article, we first describe codimension two regular foliations with numerically trivial canonical class on complex projective manifolds whose canonical class is not numerically effective. Building on a recent algebraicity criterion…

Algebraic Geometry · Mathematics 2023-06-22 Stéphane Druel

Let X be a simply connected projective manifold with nef anticanonical bundle. We prove that X is a product of a rationally connected manifold and a manifold with trivial canonical bundle. As an application we describe the MRC fibration of…

Algebraic Geometry · Mathematics 2017-06-28 Junyan Cao , Andreas Höring

We investigate the accumulation to singular points of leaves of codimension one foliations whose normal bundle is ample, with emphasis on the nonexistence of Levi-flat hypersurfaces.

Complex Variables · Mathematics 2007-06-12 Marco Brunella

In this work we consider compact K\"ahler manifolds with non-positive mixed curvature which is a "convex combination" of Ricci curvature and holomorphic sectional curvature. We show that in this case, the canonical line bundle is nef.…

Differential Geometry · Mathematics 2022-05-03 Jianchun Chu , Man-Chun Lee , Luen-Fai Tam

We show that the tangent bundle of a projective manifold with nef anticanonical class is generically nef. That is, its restriction to a curve cut out by general sufficiently ample divisors is a nef vector bundle. This confirms a conjecture…

Algebraic Geometry · Mathematics 2021-08-03 Wenhao Ou

Let $(X, \omega_X)$ be a compact K\"ahler manifold such that the anticanonical bundle $-K_X$ is nef. We prove that the slopes of the Harder-Narasimhan filtration of the tangent bundle with respect to a polarization of the form…

Algebraic Geometry · Mathematics 2014-02-27 Junyan Cao

We study holomorphic geometric structures on non-K\"ahler compact complex manifolds with trivial canonical line bundle. For Vaisman Calabi-Yau manifolds we prove that all holomorphic geometric structures of affine type on them are locally…

Differential Geometry · Mathematics 2026-05-22 Indranil Biswas , Sorin Dumitrescu

Any ample Cartier divisor D on a projective variety X is strictly nef (i.e. D.C>0 for any effective curve C on X). In general, the converse statement does not hold. But this is conjectured to be true for anticanonical divisors. The present…

Algebraic Geometry · Mathematics 2016-09-07 H. Uehara

In this paper, we prove that given a flat generically smooth morphism between smooth projective varieties with $F$-pure closed fibers, if the source space is Fano, weak Fano or a variety with the nef anti-canonical divisor, then so is the…

Algebraic Geometry · Mathematics 2019-12-11 Sho Ejiri

On compact K\"{a}hler manifolds, we classify regular holomorphic foliations of codimension 1 whose canonical bundle is numerically trivial.

Differential Geometry · Mathematics 2007-05-23 Frederic Touzet