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Related papers: Fano threefolds with sections in $\Omega_V^1(1)$

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We provide a systematic method to classify all smooth weak Fano toric varieties of Picard rank $3$ in any dimension using Macaulay2, and describe the classification explicitly in dimensions $3$ and $4$. There are $28$ and $114$ isomorphism…

Algebraic Geometry · Mathematics 2025-06-03 Zhengning Hu , Rohan Joshi

This is a survey on the Fano schemes of linear spaces, conics, rational curves, and curves of higher genera in smooth projective hypersurfaces, complete intersections, Fano threefolds, etc.

Algebraic Geometry · Mathematics 2020-07-02 Ciro Ciliberto , Mikhail Zaidenberg

This note continues our previous work on special secant defective (specifically, conic connected and local quadratic entry locus) and dual defective manifolds. These are now well understood, except for the prime Fano ones. Here we add a few…

Algebraic Geometry · Mathematics 2017-02-03 Paltin Ionescu , Francesco Russo

As an application of a recent characterization of complete flag manifolds as Fano manifolds having only ${\mathbb P}^1$-bundles as elementary contractions, we consider here the case of a Fano manifold $X$ of Picard number one supporting an…

Algebraic Geometry · Mathematics 2022-02-24 Gianluca Occhetta , Luis E. Solá Conde , Jarosław A. Wiśniewski

We show boundedness of $3$-folds of $\epsilon$-Fano type with Mori fibration structures. The proof is based on the birational boundedness result in our previous work arXiv:1509.08722 combining with arguments in Kawamata \cite{K} and…

Algebraic Geometry · Mathematics 2020-09-01 Chen Jiang

We study Gorenstein almost Fano threefolds X with canonical singularities and pseudoindex > 1. We show that the maximal Picard number of X is 10 in general, 3 if X is Fano, and 8 if X is toric. Moreover, we characterize the boundary cases.…

Algebraic Geometry · Mathematics 2007-05-23 C. Casagrande , P. Jahnke , I. Radloff

We construct a deformation family for each of the 34 Hilbert series of index 2 Fano 3-folds. In 18 cases we construct two different families, distinguished by the topology of their general members.

Algebraic Geometry · Mathematics 2022-12-05 Livia Campo

We describe the geometry of K\"uchle varieties (i.e. Fano 4-folds of index 1 contained in the Grassmannians as zero loci of equivariant vector bundles) with Picard number greater than 1 and the structure of their derived categories.

Algebraic Geometry · Mathematics 2018-09-12 Alexander Kuznetsov

The elliptic curves on a surface of general type constitute an obstruction for the cotangent sheaf to be ample. In this paper, we give the classification of the configurations of the elliptic curves on the Fano surface of a smooth cubic…

Algebraic Geometry · Mathematics 2010-01-27 Xavier Roulleau

We exhibit an example of obstructed K-polystable Fano 3-fold $X$ such that the K-moduli stack of K-semistable Fano varieties and the K-moduli space of K-polystable Fano varieties have an embedded point at $[X]$.

Algebraic Geometry · Mathematics 2025-04-03 Andrea Petracci

In our series of papers, we prove that smooth Fano threefolds in positive characteristic lift to the ring of Witt vectors. Moreover, we show that they satisfy Akizuki-Nakano vanishing, $E_1$-degeneration of the Hodge to de Rham spectral…

Algebraic Geometry · Mathematics 2025-03-14 Tatsuro Kawakami , Hiromu Tanaka

We consider the classification problem of prime $\mathbb{Q}$-Fano 3-folds with at most $1/2(1,1,1)$-singularities, which was initiated in [Taka2]. We construct two distinct classes of such 3-folds with genus one and six…

Algebraic Geometry · Mathematics 2025-11-18 Hiromichi Takagi

We prove birational superrigidity of Fano cyclic covers of index 1 over hypersurfaces in the projective space.

Algebraic Geometry · Mathematics 2007-05-23 Aleksandr V. Pukhlikov

We study the geometry and the period map of nodal complex prime Fano threefolds with index 1 and degree 10. We show that these threefolds are birationally isomorphic to Verra solids (hypersurfaces of bidegree $(2,2)$ in $ \P^2\times \P^2$).…

Algebraic Geometry · Mathematics 2015-05-18 Olivier Debarre , Atanas Iliev , Laurent Manivel

In this note we consider the problem of determining which Fano manifolds can be realised as fibres of a Mori fibre space. In particular, we study the case of toric varieties, Fano manifolds with high index and some Fano manifolds with high…

Algebraic Geometry · Mathematics 2022-11-08 Giulio Codogni , Andrea Fanelli , Roberto Svaldi , Luca Tasin

This article treats smooth weak Fano 3-folds having an extremal ray of type D. Smooth weak Fano 3-folds with an extremal ray of type D except of degree 6 are classified into 47 deformation types.

Algebraic Geometry · Mathematics 2009-10-13 Kiyohiko Takeuchi

We consider Fano threefolds $V$ with canonical Gorenstein singularities. A sharp bound $-K_V^3\le 72$ of the degree is proved.

Algebraic Geometry · Mathematics 2025-11-26 Yuri G. Prokhorov

We prove the birational boundedness of Q-Fano varieties with Picard number one and dimension $n$ for every $n$. We do not use Mori theory.

Algebraic Geometry · Mathematics 2007-05-23 Hajime Tsuji

We prove that a prime Fano threefold of genus 8 over an algebraically closed field of positive characteristic is isomorphic to a linear section of the Grassmannian variety Gr(2, 6). As applications, it is shown that a prime Fano threefold…

Algebraic Geometry · Mathematics 2026-04-13 Akihiro Kanemitsu , Hiromu Tanaka

We construct new families of smooth Fano fourfolds with Picard rank $1$ which contain open $\Bbb A^1$-cylinders, that is, Zariski open subsets of the form $Z \times \Bbb A^1$, where $Z$ is a quasiprojective variety. In particular, we show…

Algebraic Geometry · Mathematics 2021-09-27 Hang Thi Anh Nguyen , Michael Hoff , Truong Le Hoang