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The classification of toric Fano manifolds with large Picard number corresponds to the classification of smooth Fano polytopes with large number of vertices. A smooth Fano polytope is a polytope that contains the origin in its interior such…

Algebraic Geometry · Mathematics 2015-08-11 Benjamin Assarf , Benjamin Nill

In this paper, we classify Fano fourfolds whose the second exterior power of tangent bundles are numerically effective with Picard number greater than one.

Algebraic Geometry · Mathematics 2014-01-14 Kazunori Yasutake

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

We classify smooth Fano threefolds with infinite automorphism groups.

Algebraic Geometry · Mathematics 2021-06-11 Ivan Cheltsov , Victor Przyjalkowski , 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 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 classify Fano threefolds with only terminal singularities whose canonical class is Cartier and divisible by 2, and satisfying an additional assumption that the $G$-invariant part of the Weil divisor class group is of rank 1 with respect…

Algebraic Geometry · Mathematics 2013-08-06 Yuri Prokhorov

We discuss the ascending chain condition for lengths of extremal rays. We prove that the lengths of extremal rays of $n$-dimensional $\mathbb Q$-factorial toric Fano varieties with Picard number one satisfy the ascending chain condition.

Algebraic Geometry · Mathematics 2012-06-05 Osamu Fujino , Yasuhiro Ishitsuka

Ross and Thomas introduced the concept of slope stability to study K-stability, which has conjectural relation with the existence of constant scalar curvature K\"ahler metric. This paper presents a study of slope stability of Fano manifolds…

Algebraic Geometry · Mathematics 2014-02-26 Jun-Muk Hwang , Hosung Kim , Yongnam Lee , Jihun Park

We consider projective Hyper-K\"ahler manifolds of dimension four that are deformation equivalent to Hilbert squares of K3 surfaces. In case such a manifold admits a divisorial contraction, the exceptional divisor is a conic bundle over a…

Algebraic Geometry · Mathematics 2025-04-07 Federica Galluzzi , Bert Van Geemen

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 study smooth complex projective polarized varieties $(X,H)$ of dimension $ n \ge 2$ which admit a dominating family $V$ of rational curves of $H$-degree $3$, such that two general points of $X$ may be joined by a curve parametrized by…

Algebraic Geometry · Mathematics 2010-09-21 Gianluca Occhetta , Valentina Paterno

Curves of low genus on a surface carry important informations on that surface. We study the Fano surfaces of lines of cubic threefolds that contain 12 or 30 elliptic curves. We determine their Picard number and compute a basis of the…

Algebraic Geometry · Mathematics 2010-02-05 Xavier Roulleau

A projective log variety (X, D) is called "a log Fano manifold" if X is smooth and if D is a reduced simple normal crossing divisor on X with -(K_X+D) ample. The n-dimensional log Fano manifolds (X, D) with nonzero D are classified in this…

Algebraic Geometry · Mathematics 2015-01-14 Kento Fujita

In this paper we study smooth toric Fano varieties using primitive relations and toric Mori theory. We show that for any irreducible invariant divisor D in a toric Fano variety X, we have $0\leq\rho_X-\rho_D\leq 3$, for the difference of…

Algebraic Geometry · Mathematics 2007-05-23 Cinzia Casagrande

Using a construction due to C. Casagrande and further developed by the author, we prove that the Picard number of a non-smooth Fano 3-fold with isolated factorial canonical singularities, is at most 6.

Algebraic Geometry · Mathematics 2013-01-14 Gloria Della Noce

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

This is the unabridged web version of the paper that will be published on the American Journal of Mathematics. In this paper, we study the birational geometry of certain examples of mildly singular quartic 3-folds. A quartic 3-fold is an…

Algebraic Geometry · Mathematics 2007-05-23 A. Corti , M. Mella

We consider extremal contractions on smooth Fano fourfolds whose second Chern character is positive. We show that such contractions can neither be of fiber type nor contract a divisor to a point.

Algebraic Geometry · Mathematics 2014-06-13 Florian Schrack

Let $X$ be a Fano manifold of Picard number one. We establish a lower bound for the second Chern class of $X$ in terms of its index and degree. As an application, if $Y$ is a $n$-dimensional Fano manifold with $-K_Y=(n-3)H$ for some ample…

Algebraic Geometry · Mathematics 2018-05-29 Jie Liu