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For a smooth quasi-projective scheme $X$ over a field $k$ with an action of a reductive group, we establish a spectral sequence connecting the equivariant and the ordinary higher Chow groups of $X$. For $X$ smooth and projective, we show…

Algebraic Geometry · Mathematics 2016-12-01 Amalendu Krishna

Let P be a semigroup that admits an embedding into a group G. Assume that the embedding satisfies a certain Toeplitz condition and that the Baum-Connes conjecture holds for G. We prove a formula describing the K- theory of the reduced…

Operator Algebras · Mathematics 2012-05-25 Joachim Cuntz , Siegfried Echterhoff , Xin Li

We write the equivariant Todd class of a general complete toric variety as an explicit combination of the orbit closures, the coefficients being analytic functions on the Lie algebra of the torus which satisfy Danilov's requirement.

Algebraic Geometry · Mathematics 2007-05-23 Nicole Berline , Michele Vergne

We develop a Chern-Weil theory for compact Lie group action whose generic stabilizers are finite in the framework of equivariant cohomology. This provides a method of changing an equivariant closed form within its cohomological class to a…

Differential Geometry · Mathematics 2007-05-23 Huai-Dong Cao , Jian Zhou

The purpose of this article is to investigate the intersection cohomology for algebraic varieties with torus action. Given an algebraic torus $\mathbb{T}$, one of our result determines the intersection cohomology Betti numbers of any normal…

Algebraic Geometry · Mathematics 2020-05-07 Marta Agustin Vicente , Kevin Langlois

An equivariant linear system on a toric variety is a linear system invariant under the torus action. We study the number of irreducible components of the complete intersection of general divisors from a fixed collection of equivariant…

Algebraic Geometry · Mathematics 2025-08-04 Andrey Zhizhin

This paper applies the decomposition theorem in intersection cohomology to geometric invariant theory quotients, relating the intersection cohomology of the quotient to that of the semistable points for the action. Suppose a connected…

Algebraic Geometry · Mathematics 2007-05-23 Jonathan Woolf

Observations on rational Chow groups and cycle class maps in equivariant contexts.

Algebraic Geometry · Mathematics 2015-08-11 Rahbar Virk

In this paper we define twisted equivariant K-theory for actions of Lie groupoids. For a Bredon-compatible Lie groupoid, this defines a periodic cohomology theory on the category of finite CW-complexes with equivariant stable projective…

Algebraic Topology · Mathematics 2011-05-18 Jose Cantarero

We introduce the category of {\it locally $k$-standard $T$-manifolds} which includes well-known classes of manifolds such as toric and quasitoric manifolds, good contact toric manifolds and moment-angle manifolds. They are smooth manifolds…

Algebraic Topology · Mathematics 2022-01-05 Soumen Sarkar , Jongbaek Song

We present a purely algebraic proof of the commutativity of the operation defined by intersection with divisors on the Chow group of a local Noetherian domain.

Commutative Algebra · Mathematics 2008-01-02 Paul Roberts , Sandra Spiroff

Almost perfect obstruction theories were introduced in an earlier paper by the authors as the appropriate notion in order to define virtual structure sheaves and $K$-theoretic invariants for many moduli stacks of interest, including…

Algebraic Geometry · Mathematics 2020-07-15 Young-Hoon Kiem , Michail Savvas

We obtain refined generating series formulae for equivariant characteristic classes of external and symmetric products of singular complex quasi-projective varieties. More concretely, we study equivariant versions of Todd, Chern and…

Algebraic Geometry · Mathematics 2018-03-16 Laurentiu Maxim , Joerg Schuermann

In this paper we outline a recent construction of a Chern-Weil isomorphism for the equivariant Brauer group of $\mathbb R^n$ actions on a principal torus bundle, where the target for this isomorphism is a "dimensionally reduced" \vCech…

Operator Algebras · Mathematics 2011-09-06 Peter Bouwknegt , Alan Carey , Rishni Ratnam

In a previous paper we have introduced the gauge-equivariant K-theory group of a bundle endowed with a continuous action of a bundle of compact Lie groups. These groups are the natural range for the analytic index of a family of…

K-Theory and Homology · Mathematics 2007-05-23 Victor Nistor , Evgenij Troitsky

Let $G$ be a finite group acting linearly on the vector space $V$ over a field of arbitrary characteristic. The action is called {\em coregular} if the invariant ring is generated by algebraically independent homogeneous invariants and the…

Commutative Algebra · Mathematics 2019-08-15 Abraham Broer

In this paper, an intersection theory for generic differential polynomials is presented. The intersection of an irreducible differential variety of dimension $d$ and order $h$ with a generic differential hypersurface of order $s$ is shown…

Algebraic Geometry · Mathematics 2011-08-02 Xiao-Shan Gao , Wei Li , Chun-Ming Yuan

Let $T$ be a compact torus. We prove that, up to equivariant rational equivalence, the category of $T$-simply connected, $T$-finite type $T$-spaces with finitely many isotropy types is completely described by certain finite systems of…

Algebraic Topology · Mathematics 2021-06-02 Leopold Zoller

We give a proof of the $p$-adic weight monodromy conjecture for scheme-theoretic complete intersections in projective smooth toric varieties. The strategy is based on Scholze's proof in the $\ell$-adic setting, which we adapt using…

Algebraic Geometry · Mathematics 2025-06-11 Federico Binda , Hiroki Kato , Alberto Vezzani

Geometric Invariant Theory gives a method for constructing quotients for group actions on algebraic varieties which in many cases appear as moduli spaces parametrizing isomorphism classes of geometric objects (vector bundles, polarized…

alg-geom · Mathematics 2008-02-03 Igor V. Dolgachev , Yi Hu