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Related papers: Super-rigid Affine Fano Varieties

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We establish birational superrigidity for a large class of singular projective Fano hypersurfaces of index one. In the special case of isolated singularities, our result applies for instance to: (1) hypersurfaces with semi-homogeneous…

Algebraic Geometry · Mathematics 2016-04-07 Tommaso de Fernex

The aim of this note is to settle some foundational questions about the behavior of birational rigidity in extensions of algebraically closed fields.

Algebraic Geometry · Mathematics 2008-09-08 János Kollár

We classify the cones of curves of Fano varieties of dimension greater or equal than five and (pseudo)index dim X -3, describing the number and type of their extremal rays.

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

We prove that a general Fano fibration $\pi\colon V\to {\mathbb P}^1$, the fiber of which is a double Fano hypersurface of index 1, is birationally superrigid provided it is sufficiently twisted over the base. In particular, on $V$ there…

Algebraic Geometry · Mathematics 2007-05-23 Aleksandr V. Pukhlikov

We investigate the relationship between affine and Stein varieties in the context of rigid geometry. We show that the two concepts are much more closely related than in complex geometry, e.g. they are equivalent for surfaces. This rests on…

Algebraic Geometry · Mathematics 2025-04-28 Marco Maculan , Jérôme Poineau

We survey some results on the nonrationality and birational rigidity of certain hypersurfaces of Fano type. The focus is on hypersurfaces of Fano index one, but hypersurfaces of higher index are also discussed.

Algebraic Geometry · Mathematics 2014-01-08 Tommaso de Fernex

We prove that for any e>0, there exists only finitely many e-log terminal spherical Fano varieties of fixed dimension. We also introduce an invariant of a spherical subgroup H in a reductive group G which measures how nice an equivariant…

Algebraic Geometry · Mathematics 2007-05-23 Valery Alexeev , Michel Brion

This is a survey paper about a selection of recent results on the geometry of a special class of Fano varieties, which are called of K3 type. The focus is mostly Hodge-theoretical, with an eye towards the multiple connections between Fano…

Algebraic Geometry · Mathematics 2022-06-14 Enrico Fatighenti

We invent the notion of a derived and fluid variety. Fluid variety has no proper derived variety as its subvariety. We examine some properties of fluid and derived varieties. Examples of such varieties of bands are presented.

General Mathematics · Mathematics 2007-05-23 Ewa Graczynska , Dietmar Schweigert

We give a survey of the recent progress on the study of K-stability of Fano varieties by an algebro-geometric approach.

Algebraic Geometry · Mathematics 2020-11-23 Chenyang Xu

Complete intersections inside rational homogeneous varieties provide interesting examples of Fano manifolds. For example, if $X = \cap_{i=1}^r D_i \subset G/P$ is a general complete intersection of $r$ ample divisors such that $K_{G/P}^*…

Algebraic Geometry · Mathematics 2018-08-07 Chenyu Bai , Baohua Fu , Laurent Manivel

Let $X$ be a complex smooth Fano variety of dimension at least four. In this paper, we classify such $X$ when the pseudoindex is at least $n-2$ and the Picard number greater than one. We also discuss the relations between pseudoindex and…

Algebraic Geometry · Mathematics 2024-07-12 Kiwamu Watanabe

We prove that a weak Fano manifold has unobstructed deformations. For a general variety, we investigate conditions under which a variety is necessarily obstructed.

Algebraic Geometry · Mathematics 2013-05-23 Taro Sano

We show that being a general fibre of a Mori fibre space is a rather restrictive condition for a Fano variety. More specifically, we obtain two criteria (one sufficient and one necessary) for a Q-factorial Fano variety with terminal…

Algebraic Geometry · Mathematics 2016-06-09 Giulio Codogni , Andrea Fanelli , Roberto Svaldi , Luca Tasin

Determining when the birational automorphism group of a Fano variety is finite is an interesting and difficult problem. The main technique for studying this problem is by the Noether-Fano method. This method has been effective in studying…

Algebraic Geometry · Mathematics 2022-05-20 David Stapleton , Nathan Chen

For $n\geq 4$, let $X$ be a complex smooth Fano $n$-fold whose minimal anticanonical degree of non-free rational curves on $X$ is at least $n-2$. We classify extremal contractions of such varieties. As an application, we obtain a…

Algebraic Geometry · Mathematics 2024-06-04 Kiwamu Watanabe

We study the cones of q-ample divisors on smooth complex varieties. In favourable cases, we identify a part where the closure of this cone and the nef cone have the same boundary. This is especially interesting for Fano (or almost Fano)…

Algebraic Geometry · Mathematics 2016-02-17 Robert Laterveer

This paper is a survey about cylinders in Fano varieties and related problems.

Algebraic Geometry · Mathematics 2021-05-11 Ivan Cheltsov , Jihun Park , Yuri Prokhorov , Mikhail Zaidenberg

In this paper, we obtain a complete classification of smooth toric Fano varieties equipped with extremal contractions which contract divisors to curves for any dimension. As an application, we obtain a complete classification of smooth…

Algebraic Geometry · Mathematics 2007-05-23 Hiroshi Sato

Upper bounds on projective rigidity of each homogeneously embedded homogeneous variety are determined; and a new, invariant characterization of the Fubini forms is given.

Differential Geometry · Mathematics 2011-12-08 J. M. Landsberg , C. Robles