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Related papers: Toric Fano manifolds with nef tangent bundles

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For a class of monadic deformations of the tangent bundles over nef-Fano smooth projective toric varieties, we study the correlators using quantum sheaf cohomology. We prove a summation formula for the correlators, confirming a conjecture…

Algebraic Geometry · Mathematics 2015-12-01 Zhentao Lu

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 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

A simple algebraic characterization of the Fano manifolds in the class of homogeneous toric bundles over a flag manifold $G^C/P$ is provided in terms of symplectic data.

Differential Geometry · Mathematics 2007-05-23 Fabio Podesta' , Andrea Spiro

We show that the complex projective space has maximal degree (volume) among all n-dimensional Kahler-Einstein Fano manifolds admitting a holomorphic C^*-action with a finite number of fixed points. The toric version of this result,…

Differential Geometry · Mathematics 2012-04-06 Robert J. Berman , Bo Berndtsson

In this paper we study the positivity of the cotangent bundle of projective manifolds. We conjecture that the cotangent bundle is pseudoeffective if and only the manifold has non-zero symmetric differentials. We confirm this conjecture for…

Algebraic Geometry · Mathematics 2020-06-11 Andreas Höring , Thomas Peternell

We show that a strong version of the geometric Merkurjev-Panin conjecture holds for the Cox category of a projective toric variety. That is, we prove that the full strong exceptional collection of Bondal-Thomsen line bundles is invariant…

Algebraic Geometry · Mathematics 2025-12-23 Daniel Erman , Andrew Hanlon , Gaku Liu , Hailun Zheng

We consider a smooth projective morphism between smooth complex projective varieties. If the source space is a weak Fano (or Fano) manifold, then so is the target space. Our proof is Hodge theoretic. We do not need mod $p$ reduction…

Algebraic Geometry · Mathematics 2010-05-03 Osamu Fujino , Yoshinori Gongyo

On a projective surface it is well-known that the set of curves orthogonal to a nef line bundle is either finite or uncountable. We show that this dichotomy fails in higher dimension by constructing a nef line bundle on a threefold which is…

Algebraic Geometry · Mathematics 2014-10-17 John Lesieutre , John Christian Ottem

Let $f\colon X\to Y$ be a surjective morphism of Fano manifolds of Picard number 1 whose VMRTs at a general point are not dual defective. Suppose that the tangent bundle $T_X$ is big. We show that $f$ is an isomorphism unless $Y$ is a…

Algebraic Geometry · Mathematics 2024-07-30 Feng Shao , Guolei Zhong

For a Fano manifold of pseudo-index at least 3 and $c_1^2-2c_2$ nef, we show irreducibility of certain spaces of curves on the Fano manifold implies the manifold is a union of rational surfaces.

Algebraic Geometry · Mathematics 2007-05-23 A. J. de Jong , Jason Michael Starr

In this paper, we prove the ampleness conjecture and Serrano's conjecture for strictly nef divisors on K-trivial fourfolds. Specifically, we show that any strictly nef divisors on projective fourfolds with trivial canonical bundle and…

Algebraic Geometry · Mathematics 2024-01-11 Haidong Liu , Shin-ichi Matsumura

In an unpublished preprint, A. King conjectured that there are tilting bundles over projective varieties which are obtained as invariant quotients of affine spaces for linear actions of reductive groups. The goal of this paper is to give…

Algebraic Geometry · Mathematics 2009-06-19 Mihai Halic

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…

Algebraic Geometry · Mathematics 2017-11-15 Philip Sieder

Let $M$ be a smooth Fano threefold such that a canonical extension of the tangent bundle is an affine manifold. We show that $M$ is rational homogeneous.

Algebraic Geometry · Mathematics 2022-11-22 Andreas Höring , Thomas Peternell

We construct full strong exceptional collections of line bundles on smooth toric Fano Deligne-Mumford stacks of Picard number at most two and of any Picard number in dimension two. It is hoped that the approach of this paper will eventually…

Algebraic Geometry · Mathematics 2008-12-24 Lev Borisov , Zheng Hua

We exhibit full exceptional collections of vector bundles on any smooth, Fano arithmetic toric variety whose split fan is centrally symmetric.

Algebraic Geometry · Mathematics 2020-06-17 Matthew R Ballard , Alexander Duncan , Patrick K. McFaddin

We prove that the tangent bundle of a generic space of planar n-gons with specified side lengths, identified under isometry, plus a trivial line bundle is isomorphic to (n-2) times a canonical line bundle. We then discuss consequences for…

Algebraic Topology · Mathematics 2018-05-09 Donald M. Davis

We give a simple combinatorial proof of the toric version of Mori's theorem that the only $n$-dimensional smooth projective varieties with ample tangent bundle are the projective spaces $\mathbb{P}^n$.

Algebraic Geometry · Mathematics 2022-10-05 Kuang-Yu Wu

We characterize building sets whose associated nonsingular projective toric varieties are Fano. Furthermore, we show that all such toric Fano varieties are obtained from smooth Fano polytopes associated to finite directed graphs.

Algebraic Geometry · Mathematics 2020-10-14 Yusuke Suyama