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Related papers: Fano threefolds in positive characteristic I

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We determine the complete list of anticanonically embedded quasi smooth log Fano 3-folds in weighted projective 4-spaces. This implies that the Reid-Fletcher list of 95 types of anticanonically embedded quasi smooth terminal Fano threefolds…

Algebraic Geometry · Mathematics 2007-05-23 Jennifer M. Johnson , János Kollár

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 construct an explicit semistable degeneration of a Fano eightfold of index three and deduce its Hodge numbers, in particular we show that it has Picard rank one. The Fano variety is of K3 type and it is defined as a connected component…

Algebraic Geometry · Mathematics 2025-12-17 Vanja Zuliani

We show that a non-toric $\mathbb{Q}$-factorial terminal Fano threefold of Picard rank $1$ and Fano index $13$ is a weighted hypersurface of degree $12$ in $\mathbb{P}(3,4,5,6,7)$.

Algebraic Geometry · Mathematics 2026-01-22 Yuri Prokhorov

We prove that all smooth Fano threefolds with Picard rank 2 and degree 28 are K-polystable, except for some explicit cases which we describe. We also give a classification of the normal bundle of a rational normal quartic curve in a smooth…

Algebraic Geometry · Mathematics 2025-07-17 Joseph Malbon

We classify three-dimensional Fano varieties with canonical Gorenstein singularities of degree bigger than 64.

Algebraic Geometry · Mathematics 2015-05-13 Ilya Karzhemanov

We classify smooth Fano threefolds that admit degenerations to toric Fano threefolds with ordinary double points.

Algebraic Geometry · Mathematics 2018-09-11 Sergey Galkin

We show that the set of families of smooth well-formed Fano weighted complete intersections admits a natural partition with respect to the variance $\mathrm{var}(X) = \mathrm{coind}(X) - \mathrm{codim}(X)$. Moreover, we obtain the…

Algebraic Geometry · Mathematics 2023-10-23 Mikhail Ovcharenko

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

We prove that a smooth well formed Picard rank one Fano complete intersection of dimension at least 2 in a toric variety is a weighted complete intersection.

Algebraic Geometry · Mathematics 2023-02-08 Victor Przyjalkowski , Constantin Shramov

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

For fixed degree $d\leq 12$, we study the Hilbert scheme of degree $d$ smooth Fano threefolds in their anticanonical embeddings. We use this to classify all possible degenerations of these varieties to toric Fano varieties with at most…

Algebraic Geometry · Mathematics 2019-11-26 Jan Arthur Christophersen , Nathan Owen Ilten

Let X be a Fano manifold such that every rational curve in X has anticanonical degree at least the dimension of X. We prove that X is a projective space or a quadric.

Algebraic Geometry · Mathematics 2018-03-06 Thomas Dedieu , Andreas Höring

Let X be a complex Fano manifold of arbitrary dimension, and D a prime divisor in X. We consider the image H of N_1(D) in N_1(X) under the natural push-forward of 1-cycles. We show that the codimension c of H in N_1(X) is at most 8.…

Algebraic Geometry · Mathematics 2011-12-21 C. Casagrande

A smooth variety is said to satisfy Condition (A) if every finite abelian subgroup of its automorphism group has a fixed point. We classify smooth Fano 3-folds that satisfy Condition (A).

Algebraic Geometry · Mathematics 2025-05-21 Hamid Abban , Ivan Cheltsov , Takashi Kishimoto , Frederic Mangolte

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

T.Kishimoto raised the problem to classify all compactifications of contractible affine 3-folds into smooth Fano 3-folds with second Betti number two and classified such compactifications whose log canonical divisors are not nef. In this…

Algebraic Geometry · Mathematics 2017-08-10 Masaru Nagaoka

A Fano surface of a smooth cubic threefold X in P^4 parametrizes the lines on X. In this note, we prove that a Fano surface satisfies the Tate conjecture over a field of finite type over the prime field and characteristic not 2.

Algebraic Geometry · Mathematics 2013-04-16 Xavier Roulleau

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 investigate Fano manifolds whose Chern characters satisfy some positivity conditions. We prove that such manifolds admit long chains of higher order minimal families of rational curves and are covered by higher rational…

Algebraic Geometry · Mathematics 2024-07-19 Taku Suzuki
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