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In this paper, we study the Chern character operators on the equivariant cohomology of the Hilbert schemes of points in the complex affine plane $C^2$ with the action of the torus $(C^*)^2$, and partially verify Okounkov's Conjecture [Oko,…

Algebraic Geometry · Mathematics 2025-05-21 Mazen M. Alhwaimel , Zhenbo Qin

We prove, for quasicompact separated schemes over ground fields, that Cech cohomology coincides with sheaf cohomology with respect to the Nisnevich topology. This is a partial generalization of Artin's result that for noetherian schemes…

Algebraic Geometry · Mathematics 2017-06-14 Stefan Schröer

In previous work we generalised both the odd and even local index formula of Connes and Moscovici to the case of spectral triples for a *-subalgebra \A of a general semifinite von Neumann algebra. Our proofs are novel even in the setting of…

Operator Algebras · Mathematics 2007-05-23 Alan L. Carey , John Phillips , Adam Rennie , Fyodor A. Sukochev

The purpose of this work is to provide details about the construction of the Chern character for categorical sheaves mentioned in our previous work "Chern character, loop spaces and derived algebraic geometry". For this, we introduce and…

Algebraic Geometry · Mathematics 2011-02-15 B. Toen , G. Vezzosi

The engineering of topological non-trivial states of matter, using cold atoms, has made great progress in the last decade. Driven by experimental successes, it has become of major interest in the cold atom community. In this work we…

Quantum Gases · Physics 2020-06-16 Urs Gebert , Bernhard Irsigler , Walter Hofstetter

We use obstruction theory based on the unstable Adams spectral sequence to construct self maps of finite quaternionic projective spaces. As a result, a conjecture of Feder and Gitler regarding the classification of self maps up to homology…

Algebraic Topology · Mathematics 2014-06-23 Gustavo Granja

We observe that certain equivariant intersection numbers of Chern characters of tautological sheaves on Hilbert schemes for suitable circle actions can be computed using the Bloch-Okounkov formula, hence they are related to Gromov-Witten…

Algebraic Geometry · Mathematics 2018-01-30 Jian Zhou

The aim of this note is to point out that Chern characters can be computed using curvatures o ``super-connections up to homotopy'. We also present an application to the vanishing theorem for Lie algebroids which is at the origin of new…

Differential Geometry · Mathematics 2007-05-23 Marius Crainic

We show that the bivariant Chern character in entire cyclic cohomology constructed in a previous paper in terms of superconnections and heat kernel regularization, retracts on periodic cocycles under some finite summability conditions. The…

Mathematical Physics · Physics 2007-05-23 Denis Perrot

It is commonly believed that nonuniform Berry curvature destroys the Girvin-MacDonald-Platzman algebra and as a consequence destabilizes fractional Chern insulators. In this work we disprove this common lore by presenting a theory for all…

Mesoscale and Nanoscale Physics · Physics 2023-09-26 Jie Wang , Semyon Klevtsov , Zhao Liu

We show a quantum version of Chern character homomorphism from the small quantum K-theory to the small quantum cohomology in the cases of projective spaces and incidence varieties, whose classical limit gives the classical Chern character…

Algebraic Geometry · Mathematics 2025-07-17 Hua-Zhong Ke , Changzheng Li , Jiayu Song

We show that Quillen's formalism for computing the Chern character of the index using superconnections extends to arbitrary operators with functional calculus. We thus remove the condition that the operators have, up to homotopy, a gap in…

funct-an · Mathematics 2008-02-03 Victor Nistor

The Chern character maps are one of the most important working tools in mathematics. Although they admit numerous different constructions, they are not yet fully understood at the conceptual level. In this note we eliminate this gap by…

K-Theory and Homology · Mathematics 2010-02-22 Goncalo Tabuada

Using similarities between topological $K$-theory and periodic cyclic homology we show that, after tensoring with $\mathbb C$, for certain Fr\'echet algebras the Chern character provides an isomorphism between these functors. This is…

K-Theory and Homology · Mathematics 2008-09-29 Maarten Solleveld

In this paper we construct a bivariant Chern character defined on ``families of spectral triples''. Such families should be viewed as a version of unbounded Kasparov bimodules adapted to the category of bornological algebras. The Chern…

Mathematical Physics · Physics 2009-11-07 Denis Perrot

Using equivariant obstruction theory we construct equivariant maps from certain classifying spaces to representation spheres for cyclic groups, product of elementary Abelian groups and dihedral groups. Restricting them to finite skeleta…

Algebraic Topology · Mathematics 2016-07-22 Samik Basu , Surojit Ghosh

We develop a theory of ``ad hoc'' Chern characters for twisted matrix factorizations associated to a scheme $X$, a line bundle ${\mathcal L}$, and a regular global section $W \in \Gamma(X, {\mathcal L})$. As an application, we establish the…

Algebraic Geometry · Mathematics 2014-04-02 Mark E. Walker

Cheeger-Simons differential characters, Deligne cohomology in the smooth category, the Hopkins-Singer construction of ordinary differential cohomology and the recent Harvey-Lawson constructions are each in two distinct ways Abelian group…

Algebraic Topology · Mathematics 2014-02-26 James Simons , Dennis Sullivan

We generalize the decomposition theorem of Hochschild, Kostant and Rosenberg for Hochschild (co-)homology to arbitrary morphisms between complex spaces or schemes over a field of characteristic zero. To be precise, we show that for each…

Algebraic Geometry · Mathematics 2007-05-23 Ragnar-Olaf Buchweitz , Hubert Flenner

We study intersection theory and Chern classes of reflexive sheaves on normal varieties. In particular, we define generalization of Mumford's intersection theory on normal surfaces to higher dimensions. We also define and study the second…

Algebraic Geometry · Mathematics 2025-07-11 Adrian Langer