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Related papers: Fano varieties with large Seshadri constants

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Let $X$ be a complex smooth Fano variety of dimension $n$. In this paper, we give a classification of such $X$ when the pseudoindex is equal to $\dfrac{\dim X+1}{2}$ and the Picard number greater than one.

Algebraic Geometry · Mathematics 2024-09-23 Kiwamu Watanabe

We give a classification of smooth Fano fourfolds such that the base scheme of the anticanonical system is a smooth surface. As a consequence we show that there are exactly 22 deformation families of such manifolds and they are all obtained…

Algebraic Geometry · Mathematics 2025-10-27 Andreas Höring , Saverio Andrea Secci

A Fano variety of Picard number $1$ is said to be \textit{birationally solid} if it is not birational to a Mori fiber space over a positive dimensional base. In this paper we complete the classification of quasi-smooth birationally solid…

Algebraic Geometry · Mathematics 2023-09-12 Takuzo Okada

A Mukai variety is a Fano n-fold of index n-2. In this paper we study the fundamental divisor of a Mukai variety with at worst log terminal singularities. The main result is a complete classification of log terminal Mukai varieties which…

alg-geom · Mathematics 2008-02-03 Massimiliano Mella

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

Fano varieties are subvarieties of the Grassmannian whose points parametrize linear subspaces contained in a given projective variety. These expository notes give an account of results on Fano varieties of complete intersections, with a…

Algebraic Geometry · Mathematics 2012-12-05 Paul Larsen

We prove that the Fano variety of lines of a generic cubic fourfold containing a plane is isomorphic to a moduli space of twisted stable complexes on a K3 surface. On the other hand, we show that the Fano varieties are always birational to…

Algebraic Geometry · Mathematics 2011-12-26 Emanuele Macri , Paolo Stellari

We give a necessary and sufficient condition for the nonsingular projective toric variety associated to the graph cubeahedron of a finite simple graph to be Fano or weak Fano in terms of the graph.

Algebraic Geometry · Mathematics 2018-04-30 Yusuke Suyama

The notion of asymptotically log Fano varieties was given by Cheltsov and Rubinstein. We show that, if an asymptotically log Fano variety $(X, D)$ satisfies that $D$ is irreducible and $-K_X-D$ is big, then $X$ does not admit…

Algebraic Geometry · Mathematics 2015-09-10 Kento Fujita

Let X be a Fano manifold of pseudoindex i_X whose Picard number is at least two and let R be an extremal ray of X with exceptional locus Exc(R). We prove an inequality which bounds the length of R in terms of i_X and of the dimension of…

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

We prove semicontinuity properties for local positivity invariants of big and nef divisors. The usual definition of Seshadri constant and asymptotic order of vanishing along a subvariety is extended to include all seminorms in the Berkovich…

Algebraic Geometry · Mathematics 2026-05-12 Joaquim Roé , Stefano Urbinati

In this article we prove the following version of the Weak-BAB conjecture for $3$-folds in char $p>5$: Fix a DCC set $I\subset [0, 1)$ and an algebraically closed field $k$ of characteristic $p>5$. Let $\mathfrak{D}$ be a collection of klt…

Algebraic Geometry · Mathematics 2019-02-22 Omprokash Das

We classify Fano manifolds X containing a divisor E isomorphic to projective space such that the normal bundle $N_{E/X}$ is strictly negative.

Algebraic Geometry · Mathematics 2007-05-23 Toru Tsukioka

In this paper we classify n-dimensional Fano manifolds with index >=n-2 and positive second Chern character.

Algebraic Geometry · Mathematics 2012-06-08 Carolina Araujo , Ana-Maria Castravet

Given a nef and big line bundle $L$ on a projective variety $X$ of dimension $d \geq 2$, we prove that the Seshadri constant of $L$ at a very general point is larger than $(d+1)^{\frac{1}{d}-1}$. This slightly improves the lower bound $1/d$…

Algebraic Geometry · Mathematics 2022-03-15 François Ballaÿ

We prove divisorial canonicity of Fano double hypersurfaces of general position.

Algebraic Geometry · Mathematics 2009-11-13 Aleksandr Pukhlikov

Fano varieties are basic building blocks in geometry - they are `atomic pieces' of mathematical shapes. Recent progress in the classification of Fano varieties involves analysing an invariant called the quantum period. This is a sequence of…

Algebraic Geometry · Mathematics 2023-09-12 Tom Coates , Alexander M. Kasprzyk , Sara Veneziale

We give several examples of pairs of non-isomorphic cubic fourfolds whose Fano varieties of lines are birationally equivalent (and in one example isomorphic). Two of our examples, which are special families of conjecturally irrational…

Algebraic Geometry · Mathematics 2024-12-20 Corey Brooke , Sarah Frei , Lisa Marquand

In this paper we explore the connection between Seshadri constants and the generation of jets. It is well-known that one way to view Seshadri constants is to consider them as measuring the rate of growth of the number of jets that multiples…

Algebraic Geometry · Mathematics 2009-02-18 Thomas Bauer , Tomasz Szemberg

Let $X$ be a Fano type variety and $(X,\Delta)$ be a log Calabi-Yau pair with $\Delta$ a Weil divisor. If $(X,\Delta)$ admits a polarized endomorphism, then we show that $(X,\Delta)$ is a finite quotient of a toric pair. Along the way, we…

Algebraic Geometry · Mathematics 2024-03-14 Joaquín Moraga , José Ignacio Yáñez , Wern Yeong