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The (homogeneous) Essentially Isolated Determinantal Variety is the natural generalization of generic determinantal variety, and is fundamental example to study non-isolated singularities. In this paper we study the characteristic classes…

Algebraic Geometry · Mathematics 2021-04-20 Xiping Zhang

Algebraic varieties are the geometric shapes defined by systems of polynomial equations; they are ubiquitous across mathematics and science. Amongst these algebraic varieties are Q-Fano varieties: positively curved shapes which have…

Algebraic Geometry · Mathematics 2023-11-01 Tom Coates , Alexander M. Kasprzyk , Sara Veneziale

Amorphous solids remain outside of the classification and systematic discovery of new topological materials, partially due to the lack of realistic models that are analytically tractable. Here we introduce the topological Weaire-Thorpe…

Disordered Systems and Neural Networks · Physics 2020-11-20 Quentin Marsal , Daniel Varjas , Adolfo G. Grushin

Classical toric varieties are among the simplest objects in algebraic geometry. They arise in an elementary fashion as varieties parametrized by monomials whose exponents are a finite subset $\mathcal{A}$ of $\mathbb{Z}^n$. They may also be…

Algebraic Geometry · Mathematics 2018-10-11 Ata Firat Pir

The paper is based on a talk. Complete exposition is given in "Equivariant Hirzebruch class for singular varieties". Starting from the classical theory we describe Hirzebruch class and the related Todd genus of a complex singular algebraic…

Algebraic Geometry · Mathematics 2013-08-06 Andrzej Weber

We define an `enriched' notion of Chow groups for algebraic varieties, agreeing with the conventional notion for complete varieties, but enjoying a functorial push-forward for arbitrary maps. This tool allows us to glue…

Algebraic Geometry · Mathematics 2012-04-11 Paolo Aluffi

For a variety with a finitely generated total coordinate ring, we describe basic geometric properties in terms of certain combinatorial structures living in its divisor class group. For example, we describe the singularities, we calculate…

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

We describe the equivariant Chow ring of the wonderful compactification $X$ of a symmetric space of minimal rank, via restriction to the associated toric variety $Y$. Also, we show that the restrictions to $Y$ of the tangent bundle $T_X$…

Algebraic Geometry · Mathematics 2007-05-23 Michel Brion , Roy Joshua

We show that the Chern-Schwartz-MacPherson class of a hypersurface X in a nonsingular variety M `interpolates' between two other notions of characteristic classes for singular varieties, provided that the singular locus of X is smooth and…

Algebraic Geometry · Mathematics 2012-04-11 Paolo Aluffi , Jean-Paul Brasselet

Let K_0(V/X) be the relative Grothendieck group of varieties over X in obj(V), with V the category of (quasi-projective) algebraic (resp. compact complex analytic) varieties over a base field k. Then we constructed the motivic Hirzebruch…

Algebraic Geometry · Mathematics 2013-10-02 Joerg Schuermann , Shoji Yokura

The real intersection cohomology of a toric variety is described in a purely combinatorial way using methods of elementary commutative algebra only. We define, for arbitrary fans, the notion of a ``minimal extension sheaf'' on the fan as an…

Algebraic Geometry · Mathematics 2009-10-31 Karl-Heinz Fieseler

Toric varieties are a special class of rational varieties defined by equations of the form {\it monomial = monomial}. For a good brief survey of the history and role of toric varieties see [10]. Any toric variety $X$ contains a cover by…

alg-geom · Mathematics 2008-02-03 Frank DeMeyer , Tim Ford , Rick Miranda

In this paper, we give a combinatorial formula for the \v{C}ech cocycles representing the power sums of the Chern roots of a holomorphic vector bundle over a complex manifold. By an observation motivation by author's previous paper, we also…

Complex Variables · Mathematics 2018-12-27 Hanlong Fang

Let $X$ be a complete toric variety. We give a criterion to decide whether $X$ decomposes as a product of complete toric varieties by analyzing the $1$-skeleton of its fan. More precisely, we prove that any direct-sum decomposition of the…

Algebraic Geometry · Mathematics 2026-01-30 Gabriel Barría Galland

Let $X$ be a compact toric extremal K\"ahler manifold. Using the work of Sz\'ekelyhidi, we provide a combinatorial criterion on the fan describing $X$ to ensure the existence of complex deformations of $X$ that carry extremal metrics. As an…

Differential Geometry · Mathematics 2013-04-02 Yann Rollin , Carl Tipler

In this article we describe the $T_{comp}$-equivariant topological $K$-ring of a $T$-{\it cellular} complete toric variety. We further show that $K_{T_{comp}}^0(X)$ is isomorphic as an $R(T_{comp})$-algebra to the ring of piecewise Laurent…

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

We present a new method to achieve an embedded desingularization of a toric variety. Let $W$ be a regular toric variety defined by a fan $\Sigma$ and $X\subset W$ be a toric embedding. We construct a finite sequence of combinatorial…

Algebraic Geometry · Mathematics 2011-10-21 Rocio Blanco , Santiago Encinas

In this paper we study some new theories of characteristic homology classes for singular complex algebraic varieties. First we introduce a natural transformation T_{y}: K_{0}(var/X) -> H_{*}(X,Q)[y] commuting with proper pushdown, which…

Algebraic Geometry · Mathematics 2007-05-23 Jean-Paul Brasselet , Joerg Schuermann , Shoji Yokura

Topological invariants, such as the Chern number, characterise topological phases of matter. Here we provide a method to detect Chern numbers in systems with two distinct species of fermion, such as spins, orbitals or several atomic states.…

There are several ways to generalize characteristic classes for singular algebraic varieties. The simplest ones to describe are Chern-Mather classes obtained by Nash blow up. They serve as an ingredient to construct…

alg-geom · Mathematics 2007-05-23 Jean-Paul Brasselet , Andrzej Weber