English
Related papers

Related papers: Toric Fano manifolds with nef tangent bundles

200 papers

We propose a conjectural list of Fano manifolds of Picard number $1$ with pseudoeffective normalized tangent bundles, which we prove in various situations by relating it to the complete divisibility conjecture of Russo and Zak on varieties…

Algebraic Geometry · Mathematics 2022-06-09 Baohua Fu , Jie Liu

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…

Algebraic Geometry · Mathematics 2018-11-08 David Schmitz

By using the classification of Fano 3-folds we prove: Let $X$ be Fano 3-fold. Assume that the tangent bundle $T_X$ of $X$ is not stable (i.e. semi-stable or unstable). Then $b_2\geq 2$ and a relative tangent sheaf $T_{X/Y}$ of a contraction…

alg-geom · Mathematics 2008-02-03 Andreas Steffens

In a work of Costa and Mir\'{o}-Roig state the following conjecture: Every smooth complete toric Fano variety has a full strongly exceptional collection of line bundles. The goal of this article is to prove it for toric Fano 3-folds.

Algebraic Geometry · Mathematics 2010-12-30 Alessandro Bernardi , Sofia Tirabassi

We show that some important classes of weak Fano $3$-folds of Picard rank $2$ do not satisfy Bott vanishing. Using this we show that any smooth projective $3$-fold $X$ of Picard rank $2$ with $-K_X$ nef which is the image of a projective…

Algebraic Geometry · Mathematics 2025-09-05 Supravat Sarkar

For a smooth, projective family of homogeneous varieties defined over a number field, we show that if potential density holds for the rational points of the base, then it also holds for the total space. A conjecture of Campana and…

Algebraic Geometry · Mathematics 2011-02-22 J. -L. Colliot-Thélène , J. N. Iyer

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…

Algebraic Geometry · Mathematics 2007-06-13 Jaya NN Iyer

The Manin-Peyre conjecture is established for smooth spherical Fano threefolds of semisimple rank one and type N. Together with the previously solved case T and the toric cases, this covers all types of smooth spherical Fano threefolds. The…

Number Theory · Mathematics 2024-06-14 Valentin Blomer , Jörg Brüdern , Ulrich Derenthal , Giuliano Gagliardi

We classify Fano manifolds X containing a divisor E isomorphic to projective space such that the normal bundle $N_{E/X}$ is strictly negative.

Algebraic Geometry · Mathematics 2007-05-23 Toru Tsukioka

We construct examples to show that having nef cotangent bundle is not preserved under finite ramified covers. Our examples also show that a projective manifold with Stein universal cover may not have nef cotangent bundle, disproving a…

Algebraic Geometry · Mathematics 2022-02-24 Yiyu Wang

We prove Vojta's abc conjecture for projective space ${\Bbb P}^n({\Bbb C})$, assuming that the entire curves in ${\Bbb P}^n({\Bbb C})$ are highly ramified over the coordinate hyperplanes. This extends the results of Guo Ji and the…

Complex Variables · Mathematics 2026-02-11 Min Ru , Julie Tzu-Yueh Wang

We investigate when the tangent bundle of a projective manifold has a non-trivial first order (or positive-dimensional) deformation. This leads to a new conjectural characterization of the complex projective space.

Algebraic Geometry · Mathematics 2020-07-20 Thomas Peternell

Given a Fano complete intersection defined by sections of a collection nef line bundles $L_1,\ldots, L_c$ on a Fano toric manifold $Y$, a construction of Givental/Hori-Vafa provides a mirror-dual Landau-Ginzburg model. This construction…

Algebraic Geometry · Mathematics 2021-09-17 Thomas Prince

As a natural extension of the theory of uniform vector bundles on Fano manifolds, we consider uniform principal bundles, and study them by means of the associated flag bundles, as their natural projective geometric realizations. In this…

Algebraic Geometry · Mathematics 2023-02-22 Roberto Muñoz , Gianluca Occhetta , Luis E. Solá Conde

We study non-Kaehler manifolds with trivial logarithmic tangent bundle. We show that each such manifold arises as a fiber bundle with a compact complex parallelizable manifold as basis and a toric variety as fiber.

Complex Variables · Mathematics 2007-05-23 Joerg Winkelmann

We first prove Vojta's abc conjecture over function fields for Campana points on projective toric varieties with high multiplicity along the boundary. As a consequence, we obtain a version of Campana's conjecture on finite coverings of…

Algebraic Geometry · Mathematics 2025-11-04 Carlo Gasbarri , Ji Guo , Julie Tzu-Yueh Wang

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…

Algebraic Geometry · Mathematics 2012-01-06 Osamu Fujino , Yoshinori Gongyo

We consider weak Fano manifolds with small contractions obtained by blowing up successively curves and subvarieties of codimension 2 in products of projective spaces. We give a classification result for a special case. In the process of…

Algebraic Geometry · Mathematics 2016-10-25 Toru Tsukioka

We exhibit a large class of quiver moduli spaces which are Fano varieties, by studying line bundles on quiver moduli and their global sections in general, and work out several classes of examples, comprising moduli spaces of point…

Algebraic Geometry · Mathematics 2023-06-22 Hans Franzen , Markus Reineke , Silvia Sabatini

In this paper, we prove a special case of Campana--Peternell's conjecture in dimension 4. Specifically, we show that a projective smooth fourfold $X$ with $c^2_1(X)\cdot c_2(X)\neq 0$ and strictly nef anti-canonical divisor $-K_X$ is a Fano…

Algebraic Geometry · Mathematics 2023-05-10 Haidong Liu