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We study the structure of rational Picard groups of hypersurfaces of toric varieties. By using the fan structure associated to the ambient toric variety, an explicit basis of the Picard group is described by certain combinatorial data. We…

Algebraic Geometry · Mathematics 2011-07-26 Shi-shyr Roan

An induced additive action on a projective variety $X\subseteq\mathbb{P}^n$ is a regular action of the group $\mathbb{G}_a^n$ on $X$ with an open orbit that can be extended to a regular action on $\mathbb{P}^n$. Such actions are known to…

Algebraic Geometry · Mathematics 2026-05-01 Alexander Chernov

We investigate the geometrical structures of multipartite states based on construction of toric varieties. In particular, we describe pure quantum systems in terms of affine toric varieties and projective embedding of these varieties in…

Quantum Physics · Physics 2015-05-18 Hoshang Heydari

We give a new definition of smooth toric DM stacks in the same spirit of toric varieties. We show that our definition is equivalent to the one of Borisov, Chen and Smith in terms of stacky fans. In particular, we give a geometric…

Algebraic Geometry · Mathematics 2009-09-22 Barbara Fantechi , Etienne Mann , Fabio Nironi

We formulate a combinatorial version of the Intersection Hodge Conjecture for projective toric varieties. The conjecture asserts that the subspace of rational Hodge classes in the intersection cohomology $IH^*(X_\Sigma)$ is generated by the…

Algebraic Geometry · Mathematics 2025-12-09 Rizwan Jahangir

In this paper, we investigate birational toric morphisms between quantum toric stacks -- namely, toric (analytic) stacks associated with fans whose cones may be irrational -- focusing on two primary classes of examples: weighted blow-ups…

Algebraic Geometry · Mathematics 2026-01-15 Antoine Boivin

We investigate toric varieties defined by arrangements of hyperplanes and call them strongly symmetric. The smoothness of such a toric variety translates to the fact that the arrangement is crystallographic. As a result, we obtain a…

Algebraic Geometry · Mathematics 2015-01-14 M. Cuntz , Y. Ren , G. Trautmann

In 1973 V.L.Popov classified affine SL(2)-embeddings. He proved that a locally transitive SL(2)-action on a normal affine three-dimensional variety X is uniquely determined by a pair (p/q, r), where 0<p/q<=1 is an uncancelled fraction and r…

Algebraic Geometry · Mathematics 2009-11-13 Sergey A. Gaifullin

We propose new definitions of integral, reduced, and normal superrings and superschemes to properly establish the notion of a supervariety. We generalize several results about classical reduced rings and varieties to the supergeometric…

Algebraic Geometry · Mathematics 2025-03-11 Eric Jankowski

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 introduce a notion of stable spherical variety which includes the spherical varieties under a reductive group $G$ and their flat equivariant degenerations. Given any projective space $\bP$ where $G$ acts linearly, we construct a moduli…

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

We prove that any affine, resp. polarized projective, spherical variety admits a flat degeneration to an affine, resp. polarized projective, toric variety. Motivated by Mirror Symmetry, we give conditions for the limit toric variety to be a…

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

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

A fundamental result of toric geometry is that there is a bijection between toric varieties and fans. More generally, it is known that some class of manifolds having well-behaved torus actions, called topological toric manifolds $M^{2n}$,…

Algebraic Topology · Mathematics 2017-01-10 Suyoung Choi , Hanchul Park

The space of torus translations and degenerations of a projective toric variety forms a toric variety associated to the secondary fan of the integer points in the polytope corresponding to the toric variety. This is used to identify a…

Algebraic Geometry · Mathematics 2020-12-22 Ata Pir , Frank Sottile

Let K be an algebraically closed field of characteristic zero, G_m=(K\{0},*) be its multiplicative group, and G_a=(K,+) be its additive group. Consider a commutative linear algebraic group G=G_m^r\times G_a. We study equivariant…

Algebraic Geometry · Mathematics 2015-10-21 Ivan Arzhantsev , Polina Kotenkova

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

We apply a Mayer-Vietoris sequence argument to identify the Atiyah-Segal equivariant complex K-theory rings of certain toric varieties with rings of integral piecewise Laurent polynomials on the associated fans. We provide necessary and…

K-Theory and Homology · Mathematics 2018-08-02 Tara S. Holm , Gareth Williams

This paper addresses the problem of constructing a cycle-level intersection theory for toric varieties. We show that by making one global choice, we can determine a cycle representative for the intersection of an equivariant Cartier divisor…

Algebraic Geometry · Mathematics 2007-05-23 Hugh Thomas

The extension from toric varieties to quantum toric stacks allows for the study of moduli spaces of toric objects with fixed combinatorial structures, as we now consider general finitely generated subgroups of $\mathbb{R}^n$ as "lattices."…

Algebraic Geometry · Mathematics 2025-04-03 Antoine Boivin