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相关论文: On generic nefness of tangent sheaves

200 篇论文

In the first part of this note, we discuss the compact K\"ahler manifold with a strongly pseudo-effective tangent bundle. In the second part, we give new proof of the fact that the only projective manifolds with the big tangent bundle are…

微分几何 · 数学 2024-01-02 Xiaojun Wu

In this paper we study normal surfaces whose anticanonical divisors are strictly nef, i.e. (-K)C>0 for every curve C.

代数几何 · 数学 2007-05-23 Mikhail Grinenko

This paper generalises Mori's famous theorem about "Projective manifolds with ample tangent bundles" to normal projective varieties in the following way: A normal projective variety over $\mathbb{C}$ with ample tangent sheaf is isomorphic…

代数几何 · 数学 2017-11-15 Philip Sieder

Given a covering f: X \to Y of projective manifolds, we consider the vector bundle E on Y given as the dual of f_*(\O_X) / \O_Y. This vector bundles often has positivity properties, e.g. E is ample when Y is projective space by a theorem of…

代数几何 · 数学 2007-05-23 Thomas Peternell , Andrew J. Sommese

In this paper, we extend the structure theorem for smooth projective varieties with nef tangent bundle to projective klt varieties whose tangent sheaf is either positively curved or almost nef. Specifically, we show that such a variety $X$,…

代数几何 · 数学 2025-07-23 Masataka Iwai , Shin-ichi Matsumura , Guolei Zhong

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

代数几何 · 数学 2024-05-10 Snehajit Misra

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…

代数几何 · 数学 2021-08-10 Jingcao Wu

Much inspired by J. A. Wi\'sniewski's nef-value function method, we prove that in a smooth projective family over the unit disk, if the adjoint bundle of the canonical line bundle with a relatively semiample line bundle is nef on one fiber,…

代数几何 · 数学 2025-10-29 Mu-Lin Li , Sheng Rao , Kai Wang

In this paper, we investigate Murre's conjectures on the structure of rational Chow groups and exhibit explicit Chow--Kuenneth projectors for some examples. More precisely, the examples we study are the varieties which have a nef tangent…

代数几何 · 数学 2007-06-13 Jaya NN Iyer

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…

代数几何 · 数学 2019-12-11 Sho Ejiri

S. Kov\'acs proposed a conjecture on rigidity results induced by ample subsheaves of some exterior power of tangent bundles for projective manifolds. We verify the conjecture in the case of second exterior products under a rank condition.…

代数几何 · 数学 2023-12-29 Yuting Liu

We establish the Miyaoka-Yau inequality in terms of orbifold Chern classes for the tangent sheaf of any complex projective variety of general type with klt singularities and nef canonical divisor. In case equality is attained for a variety…

代数几何 · 数学 2020-06-18 Daniel Greb , Stefan Kebekus , Thomas Peternell , Behrouz Taji

In this paper, for compact K\"ahler manifolds with nef cotangent bundle, we study the abundance conjecture and the associated Iitaka fibrations. We show that, for a minimal compact K\"ahler manifold, the second Chern class vanishes if and…

代数几何 · 数学 2022-05-24 Masataka Iwai , Shin-ichi Matsumura

The purpose of this paper is to translate positivity properties of the tangent bundle (and the anti-canonical bundle) of an algebraic manifold into existence and movability properties of rational curves and to investigate the impact on the…

代数几何 · 数学 2016-09-06 Frédéric Campana , Thomas Peternell

We consider a smooth projective surjective morphism between smooth complex projective varieties. We give a Hodge theoretic proof of the following well-known fact: If the anti-canonical divisor of the source space is nef, then so is the…

代数几何 · 数学 2012-01-06 Osamu Fujino , Yoshinori Gongyo

We show that a proper algebraic n-dimensional scheme Y admits nontrivial vector bundles of rank n, even if Y is non-projective, provided that there is a modification containing a projective Cartier divisor that intersects the exceptional…

代数几何 · 数学 2015-08-25 Markus Perling , Stefan Schroeer

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.

代数几何 · 数学 2024-10-08 Paolo Cascini , Tatsuro Kawakami , Shunsuke Takagi

We prove that for smooth projective threefolds whose anticanonical divisors are nef, the second Chern classes are pseudo-effective under a weak assumption. As an application, the pseudo-effectivity of the second Chern classes implies that…

代数几何 · 数学 2007-05-23 Qihong Xie

In characteristic $0$, the Campana-Peternell conjecture claims that the only smooth Fano variety with nef tangent bundle should be homogeneous. In this paper, we study the positive characteristic version of the Campana-Peternell conjecture.…

代数几何 · 数学 2022-11-01 Yuta Takahashi , Kiwamu Watanabe

We study the positivity of exterior powers of the tangent sheaf on toric varieties in order to generalize results by Campana and Peternell about 3-folds with nef second exterior power of the tangent bundle. Using the theory of equivariant…

代数几何 · 数学 2018-11-08 David Schmitz