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Related papers: On foliations with nef anti-canonical bundle

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We describe the structure of regular codimension $1$ foliations with numerically projectively flat tangent bundle on complex projective manifolds of dimension at least $4$. Along the way, we prove that either the normal bundle of a regular…

Algebraic Geometry · Mathematics 2024-01-09 Stéphane Druel

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

Up to finite \'etale cover, any smooth complex projective variety $X$ with nef anti-canonical bundle is a holomorphic fibre bundle over a $K$-trivial variety with locally constant transition functions. We show that this result is optimal by…

Algebraic Geometry · Mathematics 2025-03-26 Niklas Müller

Let X be a compact K\"ahler manifold such that the anticanonical bundle $-K_X$ is nef. A classical conjecture claims that the Albanese map is submersive. We prove this conjecture if the general fibre is a weak Fano manifold. If X is…

Algebraic Geometry · Mathematics 2017-10-30 Junyan Cao , Andreas Höring

In continuation of our paper in Math. Ann. 333 we classify smooth complex projective threefolds X with -K_X big and nef but not ample and Picard number 2, whose anticanonical map is small. We assume also that the Mori contraction of X and…

Algebraic Geometry · Mathematics 2007-10-16 Priska Jahnke , Thomas Peternell , Ivo Radloff

In this paper, we prove that a non-projective compact K\"ahler three-fold with nef anti-canonical bundle is, up to a finite \'etale cover, one of the following: a manifold with vanishing first Chern class; the product of a K3 surface and…

Algebraic Geometry · Mathematics 2025-01-09 Shin-ichi Matsumura , Xiaojun Wu

Let $X$ a projective manifold equipped with a codimension $1$ (maybe singular) distribution whose conormal sheaf is assumed to be pseudoeffective. By a theorem of Jean-Pierre Demailly, this distribution is actually integrable and thus…

Algebraic Geometry · Mathematics 2014-04-29 Frederic Touzet

We prove that a smooth complex projective threefold with a K\"ahler metric of negative holomorphic sectional curvature has ample canonical line bundle. In dimensions greater than three, we prove that, under equal assumptions, the nef…

Algebraic Geometry · Mathematics 2009-09-02 Gordon Heier , Steven S. Y. Lu , Bun Wong

In this paper, we study the structure of projective space bundles whose relative anti-canonical line bundle is nef. As an application, we get a characterization of abelian varieties up to finite etale covering.

Algebraic Geometry · Mathematics 2011-10-10 Kazunori Yasutake

We show that an everywhere regular foliation $\mathcal F$ with compact canonically polarized leaves on a quasi-projective manifold $X$ has isotrivial family of leaves when the orbifold base of this family is special. By a recent work of…

Algebraic Geometry · Mathematics 2017-09-22 Ekaterina Amerik , Frédéric Campana

In this note, we describe the structure of regular foliations with semi-positive anti-canonical bundle on smooth projective varieties.

Algebraic Geometry · Mathematics 2018-10-17 Stéphane Druel

We show that the orbifold fundamental group of an effective compact K{\"a}hler orbifold with nef anticanonical bundle has polynomial growth, which generalizes M.P \u{a}un's results for manifolds [P \u{a}u97, Theorem 1,Theorem 2]

Algebraic Geometry · Mathematics 2022-01-25 Zhining Liu

We study the geometry of projective manifolds whose tangent bundles are nef on sufficiently general curves (i.e. the tangent bundle is generically nef) and show that manifolds whose anticanonical bundles are semi-ample have this property.…

Algebraic Geometry · Mathematics 2008-07-08 Thomas Peternell

The cotangent bundle of a non-uniruled projective manifold is generically nef, due to a theorem of Miyaoka. We show that the cotangent bundle is actually generically ample, if the manifold is of general type and study in detail the case of…

Algebraic Geometry · Mathematics 2011-06-22 Thomas Peternell

We show that a compact Kahler manifold with nonpositive holomorphic sectional curvature has nef canonical bundle. If the holomorphic sectional curvature is negative then it follows that the canonical bundle is ample, confirming a conjecture…

Differential Geometry · Mathematics 2017-10-24 Valentino Tosatti , Xiaokui Yang

We start the classification of smooth projective threefolds X whose anticanonical bundles -K_X are big and nef but not ample. In this paper we treat the case b_2(X) = 2 and the morphism associated with the base point free linear system…

Algebraic Geometry · Mathematics 2007-05-23 Priska Jahnke , Thomas Peternell , Ivo Radloff

In this paper, we prove that a compact K\"ahler manifold $X$ with the nef anti-canonical bundle $-K_{X}$ admits a locally trivial fibration $\phi \colon X \to Y$, where the fiber $F$ is a rationally connected manifold and the base $Y$ is a…

Algebraic Geometry · Mathematics 2025-07-01 Shin-ichi Matsumura , Juanyong Wang , Xiaojun Wu , Qimin Zhang

We study holomorphic foliations of codimension $k\geq 1$ on a complex manifold $X$ of dimension $n+k$ from the point of view of the exceptional minimal set conjecture. For $n\geq 2$ we show in particular that if the holomorphic normal…

Complex Variables · Mathematics 2021-07-07 Judith Brinkschulte

We consider a holomorphic foliation $\mathcal{F}$ of codimension $k\geq 1$ on a homogeneous compact K\"ahler manifold $X$ of dimension $n>k$. Assuming that the singular set $Sing(\mathcal{F})$ of $\mathcal{F}$ is contained in an absolutely…

Algebraic Geometry · Mathematics 2018-10-15 Mauricio Corrêa , Arturo Fernández-Pérez

We prove the following result that was conjectured by Brunella: Let $X$ be a compact complex manifold of dimension $\geq 3$. Let $\mathcal{F}$ be a codimension one holomorphic foliation on $X$ with ample normal bundle. Then every leaf of…

Complex Variables · Mathematics 2023-11-08 Masanori Adachi , Judith Brinkschulte
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