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Generalizing a construction of Wolfgang L\"uck and Bob Oliver, we define a good equivariant cohomology theory on the category of proper G-CW complexes when G is an arbitrary Lie group (possibly non-compact). This is done by constructing an…

Algebraic Topology · Mathematics 2010-11-02 Clément de Seguins Pazzis

Torus manifolds are topological generalization of smooth projective toric manifolds. We compute the rational cohomology ring of a class of smooth locally standard torus manifolds whose orbit space is a connected sum of simple polytopes.

Algebraic Topology · Mathematics 2018-12-10 Soumen Sarkar , Donald Stanley

Locally trivial bundles of $C^*$-algebras with fibre $D \otimes \mathcal{K}$ for a strongly self-absorbing $C^*$-algebra $D$ over a finite CW-complex $X$ form a group $E^1_D(X)$ that is the first group of a cohomology theory $E^*_D(X)$. In…

Operator Algebras · Mathematics 2026-01-08 Marius Dadarlat , James E. McClure , Ulrich Pennig

The cohomology theory known as Tmf, for "topological modular forms," is a universal object mapping out to elliptic cohomology theories, and its coefficient ring is closely connected to the classical ring of modular forms. We extend this to…

Algebraic Topology · Mathematics 2015-02-05 Michael Hill , Tyler Lawson

We introduce a notion of ellipticity of complexes of linear pseudodifferential operators acting on sections of $A$-Hilbert bundles over smooth manifolds, $A$ being a $C^*$-algebra. We prove that the cohomology groups of an $A$-elliptic…

Operator Algebras · Mathematics 2022-08-23 Svatopluk Krýsl

On a compact connected Lie group $G$, we study the global solvability and the cohomology spaces of the differential complex associated with an essentially real involutive structure that is invariant under left translations. We prove that…

Analysis of PDEs · Mathematics 2026-02-26 Gabriel Araújo , Igor A. Ferra , Max R. Jahnke , Luis F. Ragognette

For an equivariantly formal action of a compact torus $T$ on a smooth manifold $X$ with isolated fixed points we investigate the global homological properties of the graded poset $S(X)$ of face submanifolds. We prove that the condition of…

Algebraic Topology · Mathematics 2026-02-10 Anton Ayzenberg , Mikiya Masuda , Grigory Solomadin

If there exists a set of canonical classes on a compact Hamiltonian-$T$-spaces in the sense of Goldin and Tolman, we derive some formulas for certain equivariant structure constants in terms of other equivariant structure constants and the…

Symplectic Geometry · Mathematics 2016-09-29 Ho-Hon Leung

We generalize our puzzle formula for ordinary Schubert calculus on Grassmannians, to a formula for the T-equivariant Schubert calculus. The structure constants to be calculated are polynomials in {y_{i+1} - y_i}; they were shown…

Algebraic Topology · Mathematics 2010-04-26 Allen Knutson , Terence Tao

It has been shown recently by Kapustin and Tomasiello that the mathematical notion of Hamiltonian actions on twisted generalized K\"ahler manifolds is in perfect agreement with the physical notion of general $(2,2)$ gauged sigma models with…

Differential Geometry · Mathematics 2008-11-26 Yi Lin

Let X be a Zariski open subset of a compact Kaehler manifold. In this paper, we study the set $\Sigma^k(X)$ of one dimensional local systems on X with nonvanishing kth cohomology. We show that under certain conditions (X compact, X has a…

alg-geom · Mathematics 2008-02-03 Donu Arapura

We study the Duflot filtration on the Borel equivariant cohomology of smooth manifolds with a smooth $p$-torus action. We axiomatize the filtration and prove analog of several structural results about equivariant cohomology rings in this…

Algebraic Topology · Mathematics 2018-10-18 James C. Cameron

Let X be a smooth projective variety with the action of the n dimensional torus. The article describes the moduli space of torus equivariant morphisms from stable toric varieties into X as the inverse limit of the GIT quotients of X and…

Algebraic Geometry · Mathematics 2015-05-12 Andrei Mustata

We use a theorem of Tolman and Weitsman to find explicit formul\ae for the rational cohomology rings of the symplectic reduction of flag varieties in C^n, or generic coadjoint orbits of SU(n), by (maximal) torus actions. We also calculate…

Symplectic Geometry · Mathematics 2007-05-23 R. F. Goldin

In this note we present a formula for the equivariant index of the cohomological complex obtained from localization of $\mathcal{N}=2$ SYM on simply-connected compact four-manifolds with a $T^2$-action. Knowledge of said index is essential…

High Energy Physics - Theory · Physics 2022-09-20 Roman Mauch , Lorenzo Ruggeri

Extending work of Klyachko and Perling, we develop a combinatorial description of pure equivariant sheaves of any dimension on an arbitrary nonsingular toric variety $X$. Using geometric invariant theory (GIT), this allows us to construct…

Algebraic Geometry · Mathematics 2025-10-02 Martijn Kool

We study the torus-equivariant homology $H_*^T(\mathrm{Gr}_G)$ of the affine Grassmannian $\mathrm{Gr}_G$, where $G=\mathrm{Sp}_{2n}(\mathbb{C})$ is the symplectic group. This homology admits a natural ring structure and a Schubert basis,…

Representation Theory · Mathematics 2025-11-27 Takeshi Ikeda , Shinsuke Iwao , Mark Shimozono

Let $M$ be a smooth complex projective toric variety equipped with an action of a torus $T$, such that the complement $D$ of the open $T$--orbit in $M$ is a simple normal crossing divisor. Let $G$ be a complex reductive affine algebraic…

Algebraic Geometry · Mathematics 2015-07-10 Indranil Biswas , Arijit Dey , Mainak Poddar

Let X be any nonsingular complex projective variety on which a complex reductive group G acts linearly, and let X^{ss} and X^s be the sets of semistable and stable points of X in the sense of Mumford's geometric invariant theory. Then X has…

Algebraic Geometry · Mathematics 2007-05-23 Frances Kirwan

We obtain the equivariant K-homology of the classifying space \underline{E}W for W a right-angled or, more generally, an even Coxeter group. The key result is a formula for the relative Bredon homology of \underline{E}W in terms of Coxeter…

K-Theory and Homology · Mathematics 2009-08-07 Ruben Sanchez-Garcia