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Related papers: Fano threefolds in positive characteristic IV

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We prove that the Fano variety of lines of a cuspidal cyclic cubic fourfold is a symplectic variety with transversal A2-singularities and we study the properties of the nonsymplectic order three automorphism induced by the covering…

Algebraic Geometry · Mathematics 2023-03-28 Samuel Boissiere , Tobias Heckel , Alessandra Sarti

We define instanton sheaves of higher rank on smooth Fano threefolds X of Picard rank one and show that their topological classification depends on two integers, namely the rank n (or the half of it, if the Fano index of X is odd) and the…

Algebraic Geometry · Mathematics 2025-04-21 Gaia Comaschi , Daniele Faenzi

We construct prime Fano manifolds from spin representations of $Spin_n$ for $n\le 14$. In this range, and if $n\ne 13$, the projectivizations of these representations are prehomogeneous, and we deduce that our Fano manifolds are locally…

Algebraic Geometry · Mathematics 2026-05-28 Alessandro Frassineti , Laurent Manivel

In this note, we classify smooth equivariant compactifications of $\mathbb{G}_a^n$ which are Fano manifolds with index $\geq n-2$.

Algebraic Geometry · Mathematics 2018-10-16 Baohua Fu , Pedro Montero

In this paper, we study the structure of Fano fibrations of varieties admitting an int-amplified endomorphism. We prove that if a normal $\mathbb{Q}$-factorial klt projective variety $X$ has an int-amplified endomorphism, then there exists…

Algebraic Geometry · Mathematics 2020-02-05 Shou Yoshikawa

An inductive approach to classifying toric Fano varieties is given. As an application of this technique, we present a classification of the toric Fano threefolds with at worst canonical singularities. Up to isomorphism, there are 674,688…

Algebraic Geometry · Mathematics 2019-08-15 Alexander M. Kasprzyk

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

We classify terminal simplicial reflexive d-polytopes with 3d-1 vertices. They turn out to be smooth Fano d-polytopes. When d is even there is 1 such polytope up to isomorphism, while there are 2 when d is uneven.

Combinatorics · Mathematics 2007-05-23 Mikkel Øbro

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

We show that polarized endomorphisms of rationally connected threefolds with at worst terminal singularities are equivariantly built up from those on Q-Fano threefolds, Gorenstein log del Pezzo surfaces and P^1. Similar results are obtained…

Algebraic Geometry · Mathematics 2019-02-20 De-Qi Zhang

We classify complex projective manifolds $X$ for which there exists a point $a$ such that the blow-up of $X$ at $a$ is Fano.

Algebraic Geometry · Mathematics 2007-05-23 L. Bonavero , F. Campana , J. A. Wiśniewski

We analyse the local structure of the K-moduli space of Fano varieties at a toric singular K-polystable Fano 3-fold, which deforms to smooth Fano 3-folds with anticanonical volume 28 and Picard rank 4. In particular, by constructing an…

Algebraic Geometry · Mathematics 2024-10-04 Liana Heuberger , Andrea Petracci

We study smooth, complex Fano 4-folds X with a rational contraction onto a 3-fold, namely a rational map X-->Y that factors as a sequence of flips X-->X' followed by a surjective morphism X'->Y with connected fibers, where Y is normal,…

Algebraic Geometry · Mathematics 2024-10-30 Cinzia Casagrande , Saverio Andrea Secci

We announce a factorization result for equivariant birational morphisms between toric 4-folds whose source is Fano: such a morphism is always a composite of blow-ups along smooth invariant centers. Moreover, we show with a counterexample…

Algebraic Geometry · Mathematics 2007-05-23 Cinzia Casagrande

We prove that a Fano variety (with arbitrary singularities) of dimension $n$ in positive characteristic is isomorphic to $\mathbb{P}^n$ if the Seshadri constant of the anti-canonical divisor at some smooth point is greater than $n$ and…

Algebraic Geometry · Mathematics 2020-08-06 Ziquan Zhuang

We study the deformation theory of a Fano variety X with normal crossing singularities of dimension at most three. We obtain a formula for the sheaf T^1(X) of first order deformations of X in a suitable log resolution of X and its singular…

Algebraic Geometry · Mathematics 2009-07-22 Nikolaos Tziolas

We describe the Fano scheme of lines on a general cubic threefold containing a plane over a field $k$ of characteristic different from 2. Then, we use the Fano scheme to characterize rationality for such cubic threefolds over nonclosed…

Algebraic Geometry · Mathematics 2023-06-13 Corey Brooke

We study toric G-solid Fano threefolds that have at most terminal singularities, where G is an algebraic subgroup of the normalizer of a maximal torus in their automorphism groups.

Algebraic Geometry · Mathematics 2023-02-03 Ivan Cheltsov , Adrien Dubouloz , Takashi Kishimoto

Let X be the blow-up of a smooth projective 4-fold Y along a smooth curve C and let E be the exceptional divisor. Assume that X is a Fano manifold and has an elementary extremal contraction $\phi: X \to Z$ of (3,1)-type such that E is…

Algebraic Geometry · Mathematics 2007-10-10 Toru Tsukioka

The family of smooth Fano 3-folds with Picard rank 1 and anticanonical volume 4 consists of quartic 3-folds and of double covers of the 3-dimensional quadric branched along an octic surface. They can all be parametrised as complete…

Algebraic Geometry · Mathematics 2024-04-09 Hamid Abban , Ivan Cheltsov , Alexander Kasprzyk , Yuchen Liu , Andrea Petracci
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