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For every complete toric variety, there exists a projective toric variety which is isomorphic to it in codimension one. In this paper, we show that every smooth non-projective complete toric threefold of Picard number at most five becomes…

Algebraic Geometry · Mathematics 2025-07-15 Osamu Fujino , Hiroshi Sato

In the first part of this paper we study geometric formality for generalized flag manifolds, including full flag manifolds of exceptional Lie groups. In the second part we deal with the problem of the classification of invariant almost…

Differential Geometry · Mathematics 2016-04-13 Lino Grama , Caio J. C. Negreiros , Ailton R. Oliveira

We reproduce the quantum cohomology of toric varieties (and of some hypersurfaces in projective spaces) as the cohomology of certain vertex algebras with differential. The deformation technique allows us to compute the cohomology of the…

Algebraic Geometry · Mathematics 2007-05-23 F. Malikov , V. Schechtman

We define a new integral transform on the real sphere which is invariant relative to the orthogonal group and similar to the horospherical Radon transform for the hyperbolic space. This transform involves complex geometry associated with…

Representation Theory · Mathematics 2007-05-23 Simon Gindikin

We obtain an explicit presentation of the equivariant cobordism ring of a complete flag variety. An immediate corollary is a Borel presentation of the ordinary cobordism ring. Another application is an equivariant Schubert calculus in…

Algebraic Geometry · Mathematics 2014-06-06 Valentina Kiritchenko , Amalendu Krishna

Let G be a connected simply-connected reductive algebraic group. In this article, we consider the normal algebraic varieties equipped with a horospherical G-action such that the quotient of a G-stable open subset is a curve. Let X be such a…

Algebraic Geometry · Mathematics 2015-07-03 Kevin Langlois , Ronan Terpereau

In this paper, we establish an innovative framework in logarithmic Hodge theory for toroidal varieties, introducing weighted toroidal structures and developing a systematic obstruction theory for Hodge classes. Building upon recent advances…

Algebraic Geometry · Mathematics 2025-09-30 Jiaming Luo

A subvariety of a complex projective space has a well-known dual variety, which is the set of its tangent hyperplanes. The purpose of this paper is to generalise this notion for a subvariety of a quite general partial flag variety. A…

Algebraic Geometry · Mathematics 2007-05-23 Pierre-Emmanuel Chaput

Using the notion of a valuation into the semifield of piecewise linear functions, we give a classification of torus equivariant flat families of finite type over a toric variety base, by certain piecewise linear maps between fans. As a…

Algebraic Geometry · Mathematics 2022-10-12 Kiumars Kaveh , Christopher Manon

We associate to every divisorial (e.g. smooth) variety $X$ with only constant invertible global functions and finitely generated Picard group a $Pic(X)$-graded homogeneous coordinate ring. This generalizes the usual homogeneous coordinate…

Algebraic Geometry · Mathematics 2007-05-23 Florian Berchtold , Juergen Hausen

Let $B$ denote the upper triangular subgroup of $SL_2(C)$, $T$ its diagonal torus and $U$ its unipotent radical. A complex projective variety $Y$ endowed with an algebraic action of $B$ such that the fixed point set $Y^U$ is a single point,…

Algebraic Geometry · Mathematics 2007-05-23 Michel Brion , James B. Carrell

Toric quiver varieties (moduli spaces of quiver representations) are studied. Given a quiver and a weight there is an associated quasiprojective toric variety together with a canonical embedding into projective space. It is shown that for a…

Representation Theory · Mathematics 2014-02-21 M. Domokos , Dániel Joó

A covariant functor on the elliptic curves with complex multiplication is constructed. The functor takes values in the noncommutative tori with real multiplication. A conjecture on the rank of an elliptic curve is formulated.

Number Theory · Mathematics 2009-06-22 Igor Nikolaev

We construct large families of harmonic morphisms which are holomorphic with respect to Hermitian structures by finding heierarchies of Weierstrass-type representations. This enables us to find new examples of complex-valued harmonic…

dg-ga · Mathematics 2008-02-03 P. Baird , J. C. Wood

The Witt group of a smooth curve over a real closed field is explicitely calculated. The method uses a comparison theorem between the graded Witt group and the etale cohomology groups. In the second part of the paper, the torsion Picard…

Algebraic Geometry · Mathematics 2007-05-23 J-P. Monnier

We use sheaf theory and the six operations to define and study the (equivariant) homology of stacks. The construction makes sense in the algebraic, complex-analytic, or even topological categories.

Algebraic Topology · Mathematics 2025-06-06 Adeel A. Khan

In the classification of real singularities by Arnold et al. (1985), normal forms, as representatives of equivalence classes under right equivalence, are not always uniquely determined. We describe the complete structure of the equivalence…

Algebraic Geometry · Mathematics 2016-01-18 Magdaleen S. Marais , Andreas Steenpass

We study the multi-height distribution of rational points of smooth, projective and split toric varieties over $\mathbf{Q}$ using the lift of the number of points to universal torsors.

Number Theory · Mathematics 2026-03-16 Nicolas Bongiorno

The first goal of this article is to give a complete classification (up to Real biholomorphisms) of Real primary Hopf surfaces $(H,s)$, and, for any such pair, to describe in detail the following naturally associated objects : the group…

Complex Variables · Mathematics 2023-12-05 Zahraa Khaled

We classify holomorphic as well as algebraic torus equivariant principal $G$-bundles over a nonsingular toric variety $X$, where $G$ is a complex linear algebraic group. It is shown that any such bundle over an affine, nonsingular toric…

Algebraic Geometry · Mathematics 2015-10-15 Indranil Biswas , Arijit Dey , Mainak Poddar
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