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We give a classification of rank $r$ torus equivariant vector bundles $\mathcal{E}$ on a toric scheme $\mathfrak{X}$ over a discrete valuation ring $\mathcal{O}$, in terms of graded piecewise linear maps $\Phi$ from the fan of…

Algebraic Geometry · Mathematics 2025-05-02 Kiumars Kaveh , Christopher Manon , Boris Tsvelikhovskiy

We compute the cohomology rings of smooth real toric varieties and of real toric spaces, which are quotients of real moment-angle complexes by freely acting subgroups of the ambient 2-torus. The differential graded algebra we present is in…

Algebraic Topology · Mathematics 2022-06-22 Matthias Franz

We systematically produce algebraic varieties with torus action by constructing them as suitably embedded subvarieties of toric varieties. The resulting varieties admit an explicit treatment in terms of toric geometry and graded ring…

Algebraic Geometry · Mathematics 2021-02-04 Juergen Hausen , Christoff Hische , Milena Wrobel

We classify the smooth projective symmetric G-varieties with Picard number one (and G semisimple). Moreover we prove a criterion for the smoothness of the simple (normal) symmetric varieties whose closed orbit is complete. In particular we…

Algebraic Geometry · Mathematics 2008-09-26 Alessandro Ruzzi

We show that the equivariant Chow cohomology ring of a toric variety is naturally isomorphic to the ring of integral piecewise polynomial functions on the associated fan. This gives a large class of singular spaces for which localization…

Algebraic Geometry · Mathematics 2007-06-23 Sam Payne

We develop the geometric theory of equivariant quasisymmetry via a new ``quasisymmetric flag variety''. This is a toric complex in the flag variety whose fixed point set is the set of noncrossing partitions, and whose cohomology ring is the…

Algebraic Geometry · Mathematics 2025-08-19 Nantel Bergeron , Lucas Gagnon , Philippe Nadeau , Hunter Spink , Vasu Tewari

We classify all smooth projective horospherical varieties with Picard number 1. We prove that the automorphism group of any such variety X acts with at most two orbits and that this group still acts with only two orbits on X blown up at the…

Algebraic Geometry · Mathematics 2008-01-24 Boris Pasquier

We classify equivariant topological complex vector bundles over real projective plane under a compact Lie group (not necessarily effective) action. It is shown that nonequivariant Chern classes and isotropy representations at (at most)…

Group Theory · Mathematics 2011-03-15 Min Kyu Kim

In 2006 Masuda and Suh asked if two compact non-singular toric varieties having isomorphic cohomology rings are homeomorphic. In the first part of this paper we discuss this question for topological generalizations of toric varieties,…

Geometric Topology · Mathematics 2013-05-13 Michael Wiemeler

We describe the equivariant cobordism ring of smooth toric varieties. This equivariant description is used to compute the ordinary cobordism ring of such varieties.

Algebraic Geometry · Mathematics 2010-11-03 Amalendu Krishna , V. Uma

In this paper, we investigate when there exists a wild hypersurface bundle over a smooth proper toric variety in positive characteristic. In particular, we determine the possibilities for toric varieties with Picard number at most three or…

Algebraic Geometry · Mathematics 2007-05-23 Hiroshi Sato

We introduce an algebraic method for describing the Hodge filtration of degenerating hypersurfaces in projective toric varieties. For this purpose, we show some fundamental properties of logarithmic differential forms on proper equivariant…

Algebraic Geometry · Mathematics 2007-05-23 Atsushi Ikeda

Toric orbifolds are a topological generalization of projective toric varieties associated to simplicial fans. We introduce some sufficient conditions on the combinatorial data associated to a toric orbifold to ensure the existence of an…

Algebraic Geometry · Mathematics 2021-06-29 Soumen Sarkar , V. Uma

We establish a structure theorem for the connected automorphism groups of smooth complete toroidal horospherical varieties, that is, toric fibrations over rational homogeneous spaces. The key ingredient is a characterization of the Demazure…

Algebraic Geometry · Mathematics 2026-03-10 Lorenzo Barban , DongSeon Hwang , Minseong Kwon

Let $X$ be a smooth projective horospherical variety of Picard number one. We show that a uniruled projective manifold of Picard number one is biholomorphic to $X$ if its variety of minimal rational tangents at a general point is…

Algebraic Geometry · Mathematics 2024-12-24 Jaehyun Hong , Shin-young Kim

For any smooth projective variety with holomorphic locally homogeneous structure modelled on a homogeneous algebraic variety, we determine all the subvarieties of it which develop to the model.

Algebraic Geometry · Mathematics 2024-04-09 Indranil Biswas , Benjamin McKay

We describe categories of equivariant vector bundles on certain toroidal spherical varieties in linear algebra terms: vector spaces equipped with filtrations, group and Lie algebra actions, and linear maps preserving these structures.

Algebraic Geometry · Mathematics 2009-08-28 Aravind Asok , James Parson

This note is a survey on the topology of hyperplane arrangements. We mainly focus on the relationship between topology and the real structure, such as adjacent relations of chambers and stratifications related to real structures.

Geometric Topology · Mathematics 2024-08-06 Masahiko Yoshinaga

In this article we describe the equivariant and ordinary topological $K$-ring of a toric bundle with fiber a $T$-{\it cellular} toric variety. This generalizes the results in \cite{su} on $K$-theory of smooth projective toric bundles. We…

K-Theory and Homology · Mathematics 2025-02-04 V. Uma

We build new algebraic structures, which we call genuine equivariant operads, which can be thought of as a hybrid between equivariant operads and coefficient systems. We then prove an Elmendorf-Piacenza type theorem stating that equivariant…

Algebraic Topology · Mathematics 2021-06-04 Peter Bonventre , Luis A. Pereira