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Related papers: Exceptional Collections for Toric Fano Fivefolds

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For every complete toric variety, there exists a projective toric variety which is isomorphic to it in codimension one. In this paper, we show that every smooth non-projective complete toric threefold of Picard number at most five becomes…

Algebraic Geometry · Mathematics 2025-07-15 Osamu Fujino , Hiroshi Sato

Inspired by Bondal's conjecture, we study the behavior of exceptional sequences of line bundles on rational C*-surfaces under homogeneous degenerations. In particular, we provide a sufficient criterion for such a sequence to remain…

Algebraic Geometry · Mathematics 2018-01-17 Andreas Hochenegger , Nathan Owen Ilten

The purpose of this paper is to give basic tools for the classification of nonsingular toric Fano varieties by means of the notions of primitive collections and primitive relations due to Batyrev. By using them we can easily deal with…

Algebraic Geometry · Mathematics 2007-05-23 Hiroshi Sato

Split toric stacks over a number field $F$ are natural generalization of split toric varieties over $F$. Notable examples are weighted projective stacks. In our previous work, we defined heights on Deligne-Mumford stacks using so-called…

Number Theory · Mathematics 2023-11-06 Ratko Darda , Takehiko Yasuda

We prove some general results on syzygies of smooth projective varieties with numerically trivial canonical line bundle. This allows to confirm several cases of Mukai's syzygies conjecture for finite quotients of abelian varieties in any…

Algebraic Geometry · Mathematics 2025-09-22 Federico Caucci

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

Using multigraded Castelnuovo-Mumford regularity, we study the equations defining a projective embedding of a variety X. Given globally generated line bundles B_1, ..., B_k on X and integers m_1, ..., m_k, consider the line bundle L :=…

Algebraic Geometry · Mathematics 2010-03-15 Milena Hering , Hal Schenck , Gregory G. Smith

We study full exceptional collections of line bundles on surfaces. We prove that any full strong exceptional collection of line bundles on a weak del Pezzo surface of degree $\ge 3$ is an augmentation in the sense of L.Hille and M.Perling,…

Algebraic Geometry · Mathematics 2017-10-18 Alexey Elagin , Junyan Xu , Shizhuo Zhang

In this article, we study projective log smooth pairs with numerically flat normalized logarithmic tangent bundle. Generalizing works of Jahnke-Radloff and Greb-Kebekus-Peternell, we show that, passing to an appropriate finite cover and up…

Algebraic Geometry · Mathematics 2021-12-13 Stéphane Druel

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

Let $X$ be a smooth projective variety defined over an algebraically closed field of positive characteristic $p$ whose tangent bundle is nef. We prove that $X$ admits a smooth morphism $X \to M$ such that the fibers are Fano varieties with…

Algebraic Geometry · Mathematics 2020-12-18 Akihiro Kanemitsu , Kiwamu Watanabe

We present some applications of the deformation theory of toric Fano varieties to K-(semi/poly)stability of Fano varieties. First, we present two examples of K-polystable toric Fano 3-fold with obstructed deformations. In one case, the…

Algebraic Geometry · Mathematics 2021-09-02 Anne-Sophie Kaloghiros , Andrea Petracci

The main result of this paper is a structural theorem for projective Q-factorial toric varieties X in P^N, covered by lines. We prove that there exists a toric fibration f: X -> Z, locally trivial in the Zariski topology, with fiber a…

Algebraic Geometry · Mathematics 2007-05-23 C. Casagrande , S. Di Rocco

We use constructions of surfaces as abelian covers to write down exceptional collections of line bundles of maximal length for every surface $X$ in certain families of surfaces of general type with $p_g=0$ and $K_X^2=3,4,5,6,8$. We also…

Algebraic Geometry · Mathematics 2015-11-04 Stephen Coughlan

A foliation is of toric type when it has a combinatorial reduction of singularities. We show that every toric type foliation on (C3, 0), without saddle-nodes, has invariant surface. We extend the argument of Cano-Cerveau, done for the…

Algebraic Geometry · Mathematics 2020-05-19 Felipe Cano , Beatriz Molina-Samper

We study line bundles on toric DM stacks $\mathbb{P}_{\mathbf{\Sigma}}$ of dimension two. We give a combinatorial criterion of when infinitely many line bundles on $\mathbb{P}_{\mathbf{\Sigma}}$ have trivial cohomology. We further discuss…

Algebraic Geometry · Mathematics 2018-12-06 Chengxi Wang

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

Given a complex projective manifold $X$ and a divisor $D$ with normal crossings, we say that the logarithmic tangent bundle $T_X(-\log D)$ is R-flat if its pull-back to the normalization of any rational curve contained in $X$ is the trivial…

Algebraic Geometry · Mathematics 2020-08-07 Stéphane Druel , Federico Lo Bianco

This work deals with the study of embeddings of toric Calabi-Yau fourfolds which are complex cones over the smooth Fano threefolds. In particular, we focus on finding various embeddings of Fano threefolds inside other Fano threefolds and…

High Energy Physics - Theory · Physics 2016-11-23 Siddharth Dwivedi

Let X be a Fano manifold with Picard number one such that the tangent bundle T_X is big. If X admits a rational curve with trivial normal bundle, we show that X is isomorphic to the del Pezzo threefold of degree five.

Algebraic Geometry · Mathematics 2021-10-15 Andreas Höring , Jie Liu