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Related papers: Real structures on horospherical varieties

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Geometric structures modeled on rational homogeneous manifolds are studied to characterize rational homogeneous manifolds and to prove their deformation rigidity. To generalize these characterizations and deformation rigidity results to…

Algebraic Geometry · Mathematics 2017-09-29 Shin-young Kim

We study equivariant real structures on spherical varieties. We call such a structure canonical if it is equivariant with respect to the involution defining the split real form of the acting reductive group G. We prove the existence and…

Algebraic Geometry · Mathematics 2014-11-21 D. Akhiezer , S. Cupit-Foutou

We obtain a necessary and sufficient condition for the existence of equivariant real structures on complex symmetric spaces for semisimple groups and discuss how to determine the number of equivalence classes for such structures.

Algebraic Geometry · Mathematics 2021-05-25 Lucy Moser-Jauslin , Ronan Terpereau

We study the local rigidity of projective smooth horospherical varieties of rank one and Picard number two. These varieties have been already considered by the second author in a work where their automorphism groups are computed. The…

Algebraic Geometry · Mathematics 2025-12-12 Boris Pasquier , Léa Villeneuve

We establish a natural and geometric 1-1 correspondence between projective toric varieties of dimension $n$ and horofunction compactifications of $\mathbb{R}^n$ with respect to rational polyhedral norms. For this purpose, we explain a…

Metric Geometry · Mathematics 2017-05-23 Lizhen Ji , Anna-Sofie Schilling

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 describe smooth projective horospherical varieties with Picard number 1. Moreover we prove that the automorphism group of any such variety acts with at most two orbits and we give a geometric characterisation of non-homogeneous ones.

Algebraic Geometry · Mathematics 2007-05-23 Boris Pasquier

In this paper we use formal group rings to construct an algebraic model of the $T$-equivariant oriented cohomology of smooth toric varieties. Then we compare our model with known results of equivariant cohomology of toric varieties to…

Algebraic Geometry · Mathematics 2015-03-27 Wanshun Wong

A horospherical variety is a normal algebraic variety where a reductive algebraic group acts with an open orbit which is a torus bundle over a flag variety. For example, toric varieties and flag varieties are horospherical. In this paper,…

Algebraic Geometry · Mathematics 2007-05-23 Boris Pasquier

We classify real Poisson structures on complex toric manifolds of type $(1,1)$ and initiate an investigation of their Poisson cohomology. For smooth toric varieties, such structures are necessarily algebraic and are homogeneous quadratic in…

Differential Geometry · Mathematics 2017-04-07 Arlo Caine , Berit Nilsen Givens

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

We discuss an experimental approach to open problems in toric geometry: are smooth projective toric varieties (i) projectively normal and (ii) defined by degree 2 equations? We discuss the creation of lattice polytopes defining smooth toric…

Algebraic Geometry · Mathematics 2013-01-29 Winfried Bruns

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

We compute the divisor class group and the Picard group of projective varieties with Hibi rings as homogeneous coordinate rings. These varieties are precisely the toric varieties associated to order polytopes. We use tools from the theory…

Algebraic Geometry · Mathematics 2015-06-09 Tobias Friedl

We give a complete answer to the question of (semi)stability of tangent bundle of any nonsingular projective complex toric variety with Picard number 2 by using combinatorial crietrion of (semi)stability of an equivariant sheaf. We also…

Algebraic Geometry · Mathematics 2019-10-31 Jyoti Dasgupta , Arijit Dey , Bivas Khan

The equivariant cohomology of a space with a group action is not only a ring but also an algebra over the cohomology ring of the classifying space of the acting group. We prove that toric manifolds (i.e. compact smooth toric varieties) are…

Algebraic Topology · Mathematics 2008-11-28 Mikiya Masuda

We classify all smooth projective horospherical varieties of Picard group $\mathbb{Z}^2$ and we give a first description of their geometry via the Log Minimal Model Program.

Algebraic Geometry · Mathematics 2020-04-20 Boris Pasquier

A horospherical variety is a normal algebraic variety where a connected reductive algebraic group acts with an open orbit isomorphic to a torus bundle over a flag variety. In this article we study the cohomology of line bundles on complete…

Algebraic Geometry · Mathematics 2019-03-29 Benoît Dejoncheere , B. Narasimha Chary

We investigate horospherical homogeneous spaces--a class of spherical homogeneous spaces encompassing both flag varieties and algebraic tori--over fields of characteristic p>0, and establish their complete classification for p>2.

Algebraic Geometry · Mathematics 2025-09-19 Matilde Maccan , Ronan Terpereau

In the present article, we investigate the topology of real toric varieties, especially those whose torus is not split over the field of real numbers. We describe some canonical fibrations associated to their real loci. Then, we establish…

Algebraic Geometry · Mathematics 2025-10-20 Jules Chenal , Matilde Manzaroli
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