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Related papers: On torus actions of higher complexity

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We consider the action of a subtorus of the big torus on a toric variety. The aim of the paper is to define a natural notion of a quotient for this setting and to give an explicit algorithm for the construction of this quotient from the…

Algebraic Geometry · Mathematics 2007-05-23 A. A'Campo-Neuen , J. Hausen

We investigate the Cox ring of a normal complete variety X with algebraic torus action. Our first results relate the Cox ring of X to that of a maximal geometric quotient of X. As a consequence, we obtain a complete description of the Cox…

Algebraic Geometry · Mathematics 2015-03-13 Juergen Hausen , Hendrik Süß

We consider the set of forms of a toric variety over an arbitrary field: those varieties which become isomorphic to a toric variety after base field extension. In contrast to most previous work, we also consider arbitrary isomorphisms…

Algebraic Geometry · Mathematics 2016-10-04 Alexander Duncan

We consider finitely generated normal algebras over an algebraically closed field of characteristic zero that come with a complexity one grading by a finitely generated abelian group such that the conditions of a UFD are satisfied for…

Algebraic Geometry · Mathematics 2013-05-15 Juergen Hausen , Elaine Herppich

We study the equivariant cobordism rings for the action of a torus $T$ on smooth varieties over an algebraically closed field of characteristic zero. We prove a theorem describing the rational $T$-equivariant cobordism rings of smooth…

Algebraic Geometry · Mathematics 2022-11-01 Henry July

We construct all possible Hamiltonian torus actions for which all the non-empty reduced spaces are two dimensional (and not single points) and the manifold is connected and compact, or, more generally, the moment map is proper as a map to a…

Symplectic Geometry · Mathematics 2014-11-11 Yael Karshon , Susan Tolman

For an action of a compact torus $T$ on a smooth compact manifold~$X$ with isolated fixed points the number $\frac{1}{2}\dim X-\dim T$ is called the complexity of the action. In this paper we study certain examples of torus actions of…

Algebraic Topology · Mathematics 2023-02-20 Anton Ayzenberg

In this paper, we classify smooth, contractible affine varieties equipped with faithful torus actions of complexity two, having a unique fixed point and a two-dimensional algebraic quotient isomorphic to a toric blow-up of a toric surface.…

Algebraic Geometry · Mathematics 2024-11-25 Alvaro Liendo , Charlie Petitjean

We show how to construct certain homogeneous deformations for rational normal varieties with codimension one torus action. This can then be used to construct homogeneous deformations of any toric variety in arbitrary degree. For locally…

Algebraic Geometry · Mathematics 2012-11-20 Nathan Owen Ilten , Robert Vollmert

Consider an effective Hamiltonian torus action $T\times M \to M$ on a topologically twisted,generalized complex manifold $M$ of dimension $2n$. We prove that the $rank(T) \leq n-2$ and that the topological twisting survives Hamiltonian…

Differential Geometry · Mathematics 2014-02-26 Thomas Baird , Yi Lin

We consider subtorus actions on complex toric varieties. A natural candidate for a categorical quotient of such an action is the so-called toric quotient, a universal object constructed in the toric category. We prove that if the toric…

Algebraic Geometry · Mathematics 2007-05-23 Annette A'Campo-Neuen

We algorithmically compute the intersection cohomology Betti numbers of any complete normal algebraic variety with a torus action of complexity one.

Algebraic Geometry · Mathematics 2020-05-19 Marta Agustin Vicente , Kevin Langlois

We provide a complete description of normal affine algebraic varieties over the real numbers endowed with an effective action of the real circle, that is, the real form of the complex multiplicative group whose real locus consists of the…

Algebraic Geometry · Mathematics 2018-11-08 Adrien Dubouloz , Alvaro Liendo

A fundamental idea in toric topology is that classes of manifolds with well-behaved torus actions (simply, toric spaces) are classified by pairs of simplicial complexes and (non-singular) characteristic maps. The authors in their previous…

Algebraic Topology · Mathematics 2019-08-15 Suyoung Choi , Hanchul Park

We consider a normal complete rational variety with a torus action of complexity one. In the main results, we determine the roots of the automorphism group and give an explicit description of the root system of its semisimple part. The…

Algebraic Geometry · Mathematics 2014-05-08 Ivan Arzhantsev , Juergen Hausen , Elaine Herppich , Alvaro Liendo

The Chow quotient of a projective variety by the action of a complex torus is known to have a very complicated geometry, even in the case of simple varieties, such as rational homogeneous varieties. In this paper we propose an approach in…

Algebraic Geometry · Mathematics 2026-05-08 Luis E. Solá Conde , Gianluca Occhetta

Tropicalization is a procedure that assigns polyhedral complexes to algebraic subvarieties of a torus. If one fixes a weighted polyhedral complex, one may study the set of all subvarieties of a toric variety that have that complex as their…

Algebraic Geometry · Mathematics 2012-06-18 Eric Katz

A description of transitive actions of a semisimple algebraic group G on toric varieties is obtained. Every toric variety admitting such an action lies between a product of punctured affine spaces and a product of projective spaces. The…

Algebraic Geometry · Mathematics 2010-03-30 Ivan V. Arzhantsev , Sergey A. Gaifullin

We describe complete simplicial toric varieties on which a unipotent group acts with a finite number of orbits. We also provide a complete list of such varieties in the case where the dimension is equal to 2.

Algebraic Geometry · Mathematics 2025-08-05 Anton Shafarevich

We give an explicit description of the divisor class groups of rational trinomial varieties. As an application, we relate the iteration of Cox rings of any rational variety with torus action of complexity one to that of a Du Val surface.

Algebraic Geometry · Mathematics 2019-09-04 Milena Wrobel