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In the present paper we introduce and study the notion of an equivariant pretheory: basic examples include equivariant Chow groups, equivariant K-theory and equivariant algebraic cobordism. To extend this set of examples we define an…

Algebraic Geometry · Mathematics 2013-02-07 Stefan Gille , Kirill Zainoulline

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

We study a generalization of a conjecture made by Beauville on the Chow ring of hyper-K\"ahler algebraic varieties. Namely we prove in a number of cases that polynomial cohomological relations involving only CH^1(X) and the Chern classes of…

Algebraic Geometry · Mathematics 2011-11-09 C. Voisin

Let $A$, $B$ be separable C*-algebras, $B$ stable. Elements of the E-theory group $E(A,B)$ are represented by asymptotic homomorphisms from the second suspension of $A$ to $B$. Our aim is to represent these elements by (families of) maps…

Operator Algebras · Mathematics 2017-08-08 Vladimir Manuilov

Some cohomology elements, called $\nu$ classes, as a supergeneralization of universal Chern classes, are introduced for canonical super line bundles over $\nu$ projective spaces, a novel supergeometric generalization of projective spaces.…

Differential Geometry · Mathematics 2020-11-10 Marzieh Roshandelbana , Saad Varsaie

We present a geometric approach, in the spirit of the Chern-Weil theory, for constructing cocycles representing the classes of the Hopf cyclic cohomology of the Hopf algebra H(n) relative to GL(n, R). This provides an explicit description…

Differential Geometry · Mathematics 2015-02-10 Henri Moscovici

We give a definition of differentiable cohomology of a Lie group G (possibly infinite-dimensional) with coefficients in any abelian Lie group. This differentiable cohomology maps both to the cohomology of the group made discrete and to Lie…

Differential Geometry · Mathematics 2007-05-23 Jean-Luc Brylinski

In this paper, we introduce homological structure theory of semirings and CP-semirings---semirings all of whose cyclic semimodules are projective. We completely describe semisimple, Gelfand, subtractive, and anti-bounded, CP-semirings. We…

Rings and Algebras · Mathematics 2015-09-11 S. N. Il'in , Y. Katsov , T. G. Nam

We provide a formula for the Chern character of a holomorphic vector bundle in the hyper-cohomology of the de Rham complex of holomorphic sheaves on a complex manifold. This Chern character can be thought of as a completion of the Chern…

Algebraic Geometry · Mathematics 2025-04-11 Cheyne Glass , Thomas Tradler , Mahmoud Zeinalian

A quasi-representation of a group is a map from the group into a matrix algebra (or similar object) that approximately satisfies the relations needed to be a representation. Work of many people starting with Kazhdan and Voiculescu, and…

Group Theory · Mathematics 2026-05-25 Rufus Willett

We prove various finiteness and representability results for cohomology of finite flat abelian group schemes. In particular, we show that if $f\colon X\rightarrow \mathrm{Spec}(k)$ is a projective scheme over a field $k$ and $G$ is a finite…

Algebraic Geometry · Mathematics 2025-04-10 Daniel Bragg , Martin Olsson

We construct a map from $d|1$-dimensional Euclidean field theories to complexified K-theory when $d=1$ and complex analytic elliptic cohomology when $d=2$. This provides further evidence for the Stolz--Teichner program, while also…

Algebraic Topology · Mathematics 2023-08-02 Daniel Berwick-Evans

This is a further investigation of our approach to group actions in homological algebra in the settings of homology of {\Gamma}-simplicial groups, particularly of {\Gamma}-equivariant homology and cohomology of {\Gamma}-groups. This…

K-Theory and Homology · Mathematics 2021-07-26 Hvedri Inassaridze

Let G be an algebraic group and let X be a smooth integral scheme over a field k. In this paper we construct homology-type groups $H_i(X,G)$ by considering cycles in the simplicial scheme $BG\times X (an idea suggested by Andrei Suslin). We…

K-Theory and Homology · Mathematics 2007-05-23 Kevin P. Knudson , Mark E. Walker

We investigate the complexity of isomorphism relations for classes of finitely generated and n-generated computably enumerable (c.e.) algebras, presented via c.e. presentations -- that is, as quotients of term algebras over decidable sets…

Logic · Mathematics 2026-01-21 Meng-Che "Turbo" Ho , Martin Ritter , Luca San Mauro

In this paper we develop the definition of a global orthogonal spectrum and its unitary version. It relates $G-$equivariant spectra by equivariant weak equivalence in a coherent way. This category of global spectra has a model structure…

Algebraic Topology · Mathematics 2018-12-04 Zhen Huan

Over a global field (number field or function field of a curve over a finite field), theorems for the Galois cohomology of algebraic groups have long been known. For $F$ the function field of a curve over the formal series field…

Number Theory · Mathematics 2023-12-12 Dylon Chow

In 1998, Goresky, Kottwitz, and MacPherson showed that for certain projective varieties X equipped with an algebraic action of a complex torus T, the equivariant cohomology ring H_T(X) can be described by combinatorial data obtained from…

Algebraic Topology · Mathematics 2007-05-23 Megumi Harada , Andre Henriques , Tara S. Holm

We study and classify a class of representations (called generalized geometric representations) of a Coxeter group of finite rank. These representations can be viewed as a natural generalization of the geometric representation. The…

Representation Theory · Mathematics 2023-12-11 Hongsheng Hu

This work represents the concept of an n-groupoid $ \Gamma^n $ and n-characters $ \chi_n $ on n-groupoids as complex-valued maps from spaces of different classes of morphisms satisfying the condition $ \chi_n (\psi \circ_k \varphi) = \chi_n…

Algebraic Topology · Mathematics 2018-12-12 Andronick Arutyunov , Alekseev Aleksandr