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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

In this paper we extend to the singular setting the theory of Fano foliations developed in our previous paper. A Q-Fano foliation on a complex projective variety X is a foliation F whose anti-canonical class is an ample Q-Cartier divisor.…

Algebraic Geometry · Mathematics 2014-04-16 Carolina Araujo , Stéphane Druel

We address the following question: When an affine cone over a smooth Fano threefold admits an effective action of the additive group? In this paper we deal with Fano threefolds of index 1 and Picard number 1. Our approach is based on a…

Algebraic Geometry · Mathematics 2011-06-08 Takashi Kishimoto , Yuri Prokhorov , Mikhail Zaidenberg

We classify all links whose Khovanov homology have ranks no greater than 8, and all three-component links whose Khovanov homology have ranks no greater than 12, where the coefficient ring is Z/2. The classification is based on the previous…

Geometric Topology · Mathematics 2020-05-12 Yi Xie , Boyu Zhang

General hyperplane sections of a Fano threefold $Y$ of index 2 and Picard rank 1 are del Pezzo surfaces, and their Picard group is related to a root system. To the corresponding roots, we associate objects in the Kuznetsov component of $Y$…

Algebraic Geometry · Mathematics 2025-08-06 Matteo Altavilla , Marin Petkovic , Franco Rota

We show that the $\mathbb{Q}$-Fano index of a canonical weak Fano $3$-fold is at most $66$. This upper bound is optimal and gives an affirmative answer to a conjecture of Chengxi Wang in dimension $3$. During the proof, we establish a new…

Algebraic Geometry · Mathematics 2025-10-21 Chen Jiang , Haidong Liu

We classify Fano fivefolds of index two which are projectivization of rank two vector bundles over four dimensional manifolds.

Algebraic Geometry · Mathematics 2017-09-29 Carla Novelli , Gianluca Occhetta

Mukai proved that most prime Fano fourfolds of degree 10 and index 2 are contained in a Grassmannian G(2,5). They are all unirational and some are rational, as remarked by Roth in 1949. We show that their middle cohomology is of K3 type and…

Algebraic Geometry · Mathematics 2014-02-26 Olivier Debarre , Atanas Iliev , Laurent Manivel

If L is an oriented link with $n$ components, then the rank of its Khovanov homology is at least $2^n$. We classify all the links whose Khovanov homology with Z/2-coefficients achieves this lower bound, and show that such links can be…

Geometric Topology · Mathematics 2021-03-16 Yi Xie , Boyu Zhang

We study the moduli spaces of rational curves on prime Fano threefolds of index 1. For general threefolds of most genera we compute the dimension and the number of irreducible components of these moduli spaces. Our results confirm Geometric…

Algebraic Geometry · Mathematics 2019-08-26 Brian Lehmann , Sho Tanimoto

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

K{\"u}chle classified the Fano fourfolds that can be obtained as zero loci of global sections of homogeneous vector bundles on Grassmannians. Surprisingly, his classification exhibits two families of fourfolds with the same discrete…

Algebraic Geometry · Mathematics 2015-02-03 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

We completely classify the Q-factorial terminal toric Fano three-folds such that the sum of the squared torus invariant prime divisors is non-negative.

Algebraic Geometry · Mathematics 2023-02-22 Hiroshi Sato , Ryota Sumiyoshi

In continuation of our paper in Math. Ann. 333 we classify smooth complex projective threefolds X with -K_X big and nef but not ample and Picard number 2, whose anticanonical map is small. We assume also that the Mori contraction of X and…

Algebraic Geometry · Mathematics 2007-10-16 Priska Jahnke , Thomas Peternell , Ivo Radloff

In this paper we study Fano threefolds with a torsion divisor (Fano--Enriques). Due to this torsion divisor, they can be described as quotients of Fano threefolds by a finite abelian group action. We start from lists of Fano threefolds by…

Algebraic Geometry · Mathematics 2007-05-23 Jorge Caravantes

In this article, we prove the Sarkisov Program for co-rank one foliations with suitable singularities on normal projective threefolds. We also exibit a weaker version of birational super-rigidity between two foliated Mori fiber spaces with…

Algebraic Geometry · Mathematics 2026-04-01 Roktim Mascharak

We find all K-stable smooth Fano threefolds in the family No. 2.22.

Algebraic Geometry · Mathematics 2022-07-15 Ivan Cheltsov , Jihun Park

For each smooth Fano threefold $X$ with Picard number 1 we consider a weak Landau--Ginzburg model, that is a fibration over $\mathbb C^1$ given by a certain Laurent polynomial. In the spirit of L. Katzarkov's program we prove that the…

Algebraic Geometry · Mathematics 2012-10-24 Victor Przyjalkowski

Following a suggestion in a footnote of the paper \cite {Fa} by Fano, we give a direct proof of the fact that one of the two Fano threefolds of maximal degree 72 in $\p^{38}$ is isomorphic to the anticanonically embedded weighted projective…

Algebraic Geometry · Mathematics 2023-06-12 Ciro Ciliberto