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Related papers: Notes on toric varieties from Mori theoretic viewp…

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The main purpose of this notes is to supplement the paper reid, which treated Minimal Model Program (also called Mori's Program) on toric varieties. We calculate lengths of negative extremal rays of toric varieties. As an application, we…

Algebraic Geometry · Mathematics 2007-05-23 Osamu Fujino

We present a self-contained combinatorial approach to Fujita's conjectures in the toric case. Our main new result is a generalization of Fujita's very ampleness conjecture for toric varieties with arbitrary singularities. In an appendix, we…

Algebraic Geometry · Mathematics 2007-06-23 Sam Payne

We present a counterexample to the conjecture of Bihan, Franz, McCrory, and van Hamel concerning the maximality of toric varieties. There exists a six dimensional projective toric variety X with the sum of the mod 2 Betti numbers of X(R)…

Algebraic Geometry · Mathematics 2007-05-23 Valerie Hower

In this paper, we give explicit combinatorial descriptions for toric extremal contractions under the relative setting, where varieties do not need to be complete. Fujino's completion theorem is the key to the main result. As applications,…

Algebraic Geometry · Mathematics 2007-05-23 Hiroshi Sato

Let $X$ be a smooth $n$-dimensional projective variety over an algebraically closed field $k$ such that $K_X$ is not nef. We give a characterization of non nef extremal rays of $X$ of maximal length (i.e of length $n-1$); in the case of…

Algebraic Geometry · Mathematics 2007-05-23 Marco Andreatta , Gianluca Occhetta

If a toric foliation on a projective Q-factorial toric variety has an extremal ray whose length is longer than the rank of the foliation, then the associated extremal contraction is a projective space bundle and the foliation is the…

Algebraic Geometry · Mathematics 2024-03-06 Osamu Fujino , Hiroshi Sato

We totally classify the projective toric varieties whose canonical divisors are divisible by their dimensions. In Appendix, we show that Reid's toric Mori theory implies Mabuchi's characterization of the projective space for toric…

Algebraic Geometry · Mathematics 2007-05-23 Osamu Fujino

This article is based on a series of lectures on toric varieties given at RIMS, Kyoto. We start by introducing toric varieties, their basic properties and later pass to more advanced topics relating mostly to combinatorics.

Algebraic Geometry · Mathematics 2017-02-13 Mateusz Michałek

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

Jet ampleness of line bundles generalizes very ampleness by requiring the existence of enough global sections to separate not just points and tangent vectors, but also their higher order analogues called jets. We give sharp bounds…

Algebraic Geometry · Mathematics 2021-07-13 José Luis González , Zhixian Zhu

We give a new, shorter computation of Frobenius push-forwards of line bundles on toric varieties.

Algebraic Geometry · Mathematics 2010-12-13 Piotr Achinger

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

Some diophantine aspects of projective toric varieties: We present several faces of projective toric varieties, of interest from the point of view of diophantine geometry. We make explicit the theory on a number of meaningful examples and…

Number Theory · Mathematics 2007-05-23 Patrice Philippon , Martin Sombra

We discuss lengths of extremal rational curves, Fujita's freeness, and the Kodaira vanishing theorem for log canonical toric foliated pairs.

Algebraic Geometry · Mathematics 2025-03-12 Osamu Fujino , Hiroshi Sato

We prove two theorems on the derived categories of toric varieties, the existence of an exceptional collection consisting of sheaves for a divisorial extraction and the finiteness of Fourier-Mukai partners.

Algebraic Geometry · Mathematics 2012-07-02 Yujiro Kawamata

We study extremality properties of covering families of rational curves on projective varieties. Among others, we show that on a normal and Q-factorial projective variety of dimension at most 4, every covering and quasi-unsplit family of…

Algebraic Geometry · Mathematics 2007-05-23 L. Bonavero , C. Casagrande , S. Druel

Toric geometry provides a bridge between algebraic geometry and combinatorics of fans and polytopes. For each polarized toric variety (X,L) we have associated a polytope P. In this thesis we use this correspondence to study birational…

Algebraic Geometry · Mathematics 2016-11-26 Edilaine Ervilha Nobili

We discuss an experimental approach to open problems in toric geometry: are smooth projective toric varieties (i) projectively normal and (ii) defined by degree 2 equations? We discuss the creation of lattice polytopes defining smooth toric…

Algebraic Geometry · Mathematics 2013-01-29 Winfried Bruns

We consider some conditions under which a smooth projective variety X is actually the projective space. We also extend to the case of positive characteristic some results in the theory of vector bundle adjunction. We use methods and…

Algebraic Geometry · Mathematics 2007-05-23 Marco Andreatta

We prove a relative version of the theorem of Cho, Miyaoka and Shepherd-Barron: a Mori fibre space of maximal length is birational to a projective bundle.

Algebraic Geometry · Mathematics 2017-11-27 Andreas Höring , Carla Novelli
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