English
Related papers

Related papers: Fano threefolds as equivariant compactifications o…

200 papers

We show that for a weak $\mathbb{Q}$-Fano threefold $X$ ($\mathbb{Q}$-factorial with terminal singularities and $-K_X$ is nef and big) of Picard rank $\rho(X)\leq 2$, either $-K_X^3\leq 64$ or $-K_X^3=72$ and…

Algebraic Geometry · Mathematics 2025-02-28 Ching-Jui Lai , Tsung-Ju Lee

In this article, we prove that any $\Bbb Q$-factorial weak Fano 3-fold with only terminal singularities has a smoothing.

Algebraic Geometry · Mathematics 2007-05-23 Tatsuhiro Minagawa

We show that there exists a K-stable smooth Fano threefold of the Picard rank 3, the anti-canonical degree 28 and the third Betti number 2.

Algebraic Geometry · Mathematics 2021-07-13 Kento Fujita

Let X be a smooth Fano variety of dimension at least 4. We show that if X has an elementary birational contraction sending a divisor to a curve, then the Picard number of X is smaller or equal to 5.

Algebraic Geometry · Mathematics 2008-07-16 C. Casagrande

We prove the following main result: Let X be a Fano 3-fold with terminal Q-factorial singularities and X does not have a small extremal ray and a face of Kodaira dimension 1 or 2 for Mori polyhedron of X. Then the Picard number \rho (X) <…

alg-geom · Mathematics 2008-02-03 Viacheslav V. Nikulin

By identifying K-polystable limits in 4 specific deformations families of smooth Fano 3-folds, we complete the classification of one-dimensional components in the K-moduli space of smoothable Fano 3-folds.

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

We classify non-factorial nodal Fano threefolds with $1$ node and class group of rank $2$.

Algebraic Geometry · Mathematics 2024-10-04 Ivan Cheltsov , Igor Krylov , Jesus Martinez-Garcia , Evgeny Shinder

We give necessary and sufficient conditions for unirationality and rationality of Fano threefolds of geometric Picard rank-1 over an arbitrary field of zero characteristic.

Algebraic Geometry · Mathematics 2021-04-29 Alexander Kuznetsov , Yuri Prokhorov

We classify three-dimensional nodal Fano varieties that are double covers of smooth quadrics branched over intersections with quartics acted on by finite simple non-abelian groups, and study their rationality.

Algebraic Geometry · Mathematics 2018-08-07 Victor Przyjalkowski , Constantin Shramov

We construct families of non-toric $\mathbb{Q}$-factorial terminal Fano ($\mathbb{Q}$-Fano) threefolds of codimension $\geq 20$ corresponding to 54 mutation classes of rigid maximally mutable Laurent polynomials. From the point of view of…

Algebraic Geometry · Mathematics 2022-06-15 Liana Heuberger

We discuss various results on Hilbert schemes of lines and conics and automorphism groups of smooth Fano threefolds with Picard rank 1. Besides a general review of facts well known to experts, the paper contains some new results, for…

Algebraic Geometry · Mathematics 2018-09-05 Alexander Kuznetsov , Yuri Prokhorov , Constantin Shramov

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 show that, for a $\mathbb Q$-Fano threefold $X$ of Fano index 7, the inequality $\dim |-K_X| \ge 15$ implies that $X$ is isomorphic to one of the following varieties $\mathbb P (1^2,2,3)$, $X_6 \subset \mathbb P (1,2^2,3,5)$ or $X_6…

Algebraic Geometry · Mathematics 2017-08-16 Yuri Prokhorov

We classify Fano fivefolds of index two which are blow-ups of smooth manifolds along a smooth center.

Algebraic Geometry · Mathematics 2017-09-29 Elena Chierici , Gianluca Occhetta

We construct Fano threefolds with very ample anti-canonical bundle and Picard rank greater than one from cracked polytopes - polytopes whose intersection with a complete fan forms a set of unimodular polytopes - using Laurent inversion; a…

Algebraic Geometry · Mathematics 2019-07-30 Thomas Prince

We prove that Fano n-folds with nef tangent bundle and Picard number greater than n-5 are rational homogeneous manifolds.

Algebraic Geometry · Mathematics 2015-05-13 Akihiro Kanemitsu

We prove that Generalized Mukai Conjecture holds for Fano manifolds $X$ of pseudoindex $i_X \ge (\dim X +3)/3$. We also give different proofs of the conjecture for Fano fourfolds and fivefolds.

Algebraic Geometry · Mathematics 2009-12-14 Carla Novelli , Gianluca Occhetta

We classify mildly singular Fano varieties $X$ such that $\mathrm{Nef}(X)=\mathrm{Psef}(X)$ and that the Picard number of $X$ is equal to the dimension of $X$ minus $1$.

Algebraic Geometry · Mathematics 2018-04-13 Wenhao Ou

For a generic anti-canonical hypersurface in each smooth toric Fano 4-fold with rank 2 Picard group, we prove there exist three isolated rational curves in it. Moreover, for all these 4-folds except one, the contractions of generic…

Algebraic Geometry · Mathematics 2010-12-21 Jinxing Xu