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Related papers: On terminal Fano 3-folds with 2-torus action

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The anticanonical complex generalizes the Fano polytope from toric geometry and has been used to study Fano varieties with torus action so far. We work out the case of complete intersections in toric varieties defined by non-degenerate…

Algebraic Geometry · Mathematics 2025-07-01 Juergen Hausen , Christian Mauz , Milena Wrobel

We continue the classification of terminal Fano threefolds with an effective two-torus action. In earlier work we settled the Q-factorial case with Picard number one. Here we treat the larger class of varieties that do not admit any…

Algebraic Geometry · Mathematics 2018-03-13 Michele Nicolussi

The anticanonical complex is a combinatorial tool that was invented to extend the features of the Fano polytope from toric geometry to wider classes of varieties. In this note we show that the Gorenstein index of Fano varieties with torus…

Algebraic Geometry · Mathematics 2024-09-06 Philipp Iber , Eva Reinert , Milena Wrobel

We classify the non-toric, $\mathbb Q$-factorial, Gorenstein, log terminal Fano threefolds of Picard number one that admit an effective action of a two-dimensional algebraic torus.

Algebraic Geometry · Mathematics 2022-11-17 Andreas Bäuerle , Jürgen Hausen

The anticanonical complex has been introduced as a natural generalization of the toric Fano polytope and so far has been succesfully used for the study of varieties with a torus action of complexity one. In the present article we enlarge…

Algebraic Geometry · Mathematics 2019-11-07 Christoff Hische , Milena Wrobel

We classify the locally factorial Fano fourfolds of Picard number two with a hypersurface Cox ring that admit an effective action of a three-dimensional torus.

Algebraic Geometry · Mathematics 2024-02-13 Andreas Bäuerle , Christian Mauz

This paper classifies all toric Fano 3-folds with terminal singularities. This is achieved by solving the equivalent combinatoric problem; that of finding, up to the action of GL(3,Z), all convex polytopes in Z^3 which contain the origin as…

Algebraic Geometry · Mathematics 2022-10-28 Alexander Kasprzyk

We classify the canonical threefold singularities that allow an effective two-torus action. This extends classification results of Mori on terminal threefold singularities and of Ishida and Iwashita on toric canonical threefold…

Algebraic Geometry · Mathematics 2018-07-24 Lukas Braun , Daniel Hättig

Following the work of Altmann and Hausen we give a combinatorial description in terms for smooth Fano threefolds admitting a 2-torus action. We show that a whole variety of properties and invariants can be read off from this description. As…

Algebraic Geometry · Mathematics 2018-10-11 Hendrik Süß

In a first result, we describe all finitely generated factorial algebras over an algebraically closed field of characteristic zero that come with an effective multigrading of complexity one by means of generators and relations. This enables…

Algebraic Geometry · Mathematics 2011-04-26 Juergen Hausen , Elaine Herppich , Hendrik Süß

It is pretty well-known that toric Fano varieties of dimension k with terminal singularities correspond to convex lattice polytopes P in R^k of positive finite volume, such that intersection of P and Z^k consists of the point 0 and vertices…

Algebraic Geometry · Mathematics 2007-05-23 Alexandr Borisov

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

There exist exactly 166 4-dimensional reflexive polytopes such that the corresponding 4-dimensional Gorenstein toric Fano varieties have at worst terminal singularities in codimension 3 and their anticanonical divisor is divisible by 2. For…

Algebraic Geometry · Mathematics 2017-08-23 Victor Batyrev , Maximilian Kreuzer

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

We study three-dimensional Fano varieties with $\mathbb{C}^*$-action. Complementing recent results [13], we give classification results in the canonical case, where the maximal orbit quotient is $\mathbb{P}_2$ having a line arrangement of…

Algebraic Geometry · Mathematics 2019-12-18 Christoff Hische , Milena Wrobel

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

In this work we provide effective bounds and classification results for rational $\QQ$-factorial Fano varieties with a complexity-one torus action and Picard number one depending on the invariants dimension and Picard index. This…

Algebraic Geometry · Mathematics 2012-11-26 Elaine Herppich

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 classify toric Fano threefolds having at worst terminal singularities such that a rank of a $G$-invariant part of a class group equals one, where $G$ is a group acting on the variety by automorphisms.

Algebraic Geometry · Mathematics 2022-09-05 Arman Sarikyan

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
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