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Related papers: On Fano threefolds with $\mathbb{C}^*$-action

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We characterize the birational geometry of some hyperk\"ahler fourfolds of Picard rank $3$ obtained as the Fano varieties of lines on cubic fourfolds containing pairs of cubic scrolls. In each of the two cases considered, we identify all of…

Algebraic Geometry · Mathematics 2025-09-10 Corey Brooke , Sarah Frei , Lisa Marquand , Xuqiang Qin

We study the spaces of rational curves on Fano threefolds with Gorenstein terminal singularities. We generalize the results regarding Geometric Manin's Conjecture for smooth Fano threefolds, including the classification of subvarieties with…

Algebraic Geometry · Mathematics 2025-05-23 Fumiya Okamura

We study unirationality and rationality of Fano threefolds of degree 18 over nonclosed fields.

Algebraic Geometry · Mathematics 2019-10-31 Brendan Hassett , Yuri Tschinkel

We prove that $\mathbb{Q}$-Fano threefolds of Fano index $\ge 8$ are rational.

Algebraic Geometry · Mathematics 2019-03-19 Yuri Prokhorov

For a real number $0<\epsilon<1/3$, we show that the anti-canonical volume of an $\epsilon$-klt Fano $3$-fold is at most $3200/\epsilon^4$ and the order $O(1/\epsilon^4)$ is sharp.

Algebraic Geometry · Mathematics 2024-11-20 Chen Jiang , Yu Zou

Over an algebraically closed field of positive characteristic, we classify smooth Fano threefolds of Picard number one whose anti-canonical linear systems are not very ample. Furthermore, we also prove that an anti-canonically embedded Fano…

Algebraic Geometry · Mathematics 2026-03-13 Hiromu Tanaka

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 construct a $13$-dimensional affine variety $\mathscr{H}_{\mathbb{A}}^{13}$ associated with $\mathbb{P}^{2}\times\mathbb{P}^{2}$-fibrations of relative Picard number $1$. The construction is modelled on the fact that the affine cone over…

Algebraic Geometry · Mathematics 2025-10-07 Hiromichi Takagi

General linear sections of codimension 2 of the Grassmannians G(1,4) and G(1,5) appear in the classification of Fano manifolds of high index. Unlike Grassmannians, these manifolds are not homogeneous. Nevertheless, their automorphisms…

Algebraic Geometry · Mathematics 2015-05-26 Rafael Lucas de Arruda

Fano surfaces parametrize the lines of smooth cubic threefolds. In this paper, we study their quotients by some of their automorphism sub-groups. We obtain in that way some interesting surfaces of general type.

Algebraic Geometry · Mathematics 2012-02-10 Xavier Roulleau

This paper proposes the use of $F$-split and globally $F$-regular conditions in the pursuit of BAB type results in positive characteristic. The main technical work comes in the form of a detailed study of threefold Mori fibre spaces over…

Algebraic Geometry · Mathematics 2023-02-07 Liam Stigant

We classify the possible images of the action of the group of automorphisms of a smooth Fano threefold on its Picard group. We also study the first group cohomology of the Picard group for families of smooth Fano threefolds.

Algebraic Geometry · Mathematics 2025-11-18 Shreya Sharma

We prove rationality criteria over algebraically non-closed fields of characteristic $0$ for five out of six types of geometrically rational Fano threefolds of Picard number $1$ and geometric Picard number bigger than $1$. For the last type…

Algebraic Geometry · Mathematics 2022-08-04 Alexander Kuznetsov , Yuri Prokhorov

We obtain upper bounds on the number of singular points of factorial terminal Fano threefolds.

Algebraic Geometry · Mathematics 2017-08-02 Yu. Prokhorov

We survey what is known about Fano threefold weighted complete intersections from the point of view of birational rigidity.

Algebraic Geometry · Mathematics 2025-08-20 Tiago Duarte Guerreiro , Takuzo Okada

Let X be a complex, Gorenstein, Q-factorial, toric Fano variety. We prove two conjectures on the maximal Picard number of X in terms of its dimension and its pseudo-index, and characterize the boundary cases. Equivalently, we determine the…

Algebraic Geometry · Mathematics 2007-05-23 C. Casagrande

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

We study K-stability of smooth Fano threefolds of Picard rank $2$ and degree $22$ which can be obtained by blowing up a smooth complete intersection of two quadrics in $\mathbb{P}^5$ along a conic. We also describe the automorphism groups…

We consider Fano threefolds $X$ with canonical Gorenstein singularities. Under additional assumption that $X$ has at least one non-cDV point we prove a sharp bound of the degree: $-K_X^3\le 72$.

Algebraic Geometry · Mathematics 2010-05-12 Yuri G. Prokhorov

The Picard number of a Fano manifold X obtained by blowing up a curve in a smooth projective variety is known to be at most 5, in any dimension greater than or equal to 4. We show that the Picard number attains to the maximal if and only if…

Algebraic Geometry · Mathematics 2009-04-16 Toru Tsukioka