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The paper presents a classification theorem for the class of flat connections with triangular (0,1)-components on a topologically trivial complex vector bundle over a compact Kahler manifold. As a consequence we obtain several results on…

Differential Geometry · Mathematics 2007-05-23 Alexander Brudnyi

Let F be a right Hilbert C*-module over a C*-algebra B, and suppose that F is equipped with a left action, by compact operators, of a second C*-algebra A. Tensor product with F gives a functor from Hilbert C*-modules over A to Hilbert…

Operator Algebras · Mathematics 2020-06-19 Tyrone Crisp

In this article we study cohomological properties of the category of polynomial outer functors on free groups, which are the functors from the category of finitely generated free groups to the category of rational vector spaces which send…

Algebraic Topology · Mathematics 2025-08-06 Louis Hainaut

We reformulate several basic notions of notions in finite group theory in terms of iterations of the lifting property (orthogonality) with respect to particular morphisms. Our examples include the notions being nilpotent, solvable, perfect,…

Group Theory · Mathematics 2019-06-06 Misha Gavrilovich

It is a fundamental property of the Chow groups of algebraic schemes that they are contra-functorial with respect to flat morphisms between schemes. While the pullback homomorphism is easy to define at the level of algebraic cycles, the…

Algebraic Geometry · Mathematics 2022-01-25 Nitin Nitsure

We prove that the unitary equivalence classes of extensions of C*_r(G) by any sigma-unital stable C"-algebra, taken modulo extensions which split via an asymptotic homomorphism, form a group which can be calculated from the universal…

Operator Algebras · Mathematics 2009-06-09 Jonas Andersen Seebach , Klaus Thomsen

We do three things in this paper: (1) study the analog of localization sequences (in the sense of algebraic $K$-theory of stable $\infty$-categories) for additive $\infty$-categories, (2) define the notion of nilpotent extensions for…

K-Theory and Homology · Mathematics 2021-06-16 Elden Elmanto , Vladimir Sosnilo

The local classification of conformally flat Lorentzian manifolds with special holonomy groups is obtained. The corresponding local metrics are certain extensions of Riemannian spaces of constant sectional curvature to Walker metrics.

Differential Geometry · Mathematics 2018-08-21 Anton S. Galaev

We prove a number of results of the following common flavor: for a category $\mathcal{C}$ of topological or uniform spaces with all manner of other properties of common interest (separation / completeness / compactness axioms), a group (or…

Category Theory · Mathematics 2025-11-10 Alexandru Chirvasitu

The aim of this paper is to study the $(\alpha, \gamma)$-prolongation of central extensions. We obtain the obstruction theory for $(\alpha, \gamma)$-prolongations and classify $(\alpha, \gamma)$-prolongations thanks to low-dimensional…

Group Theory · Mathematics 2013-01-09 Nguyen Tien Quang , Che T. Kim Phung , Pham Thi Cuc

We study growth of 1-cocycles of locally compact groups, with values in unitary representations. Discussing the existence of 1-cocycles with linear growth, we obtain the following alternative for a class of amenable groups G containing…

Group Theory · Mathematics 2010-08-04 Yves de Cornulier , Romain Tessera , Alain Valette

In the recent article Phys. Rev. D 100, no. 4, 043533 (2019) a compact phase space generalization of the flat de Sitter cosmology has been proposed. The main advantages of the compactification is that physical quantities are bounded, and…

General Relativity and Quantum Cosmology · Physics 2021-06-09 Danilo Artigas , Sean Crowe , Jakub Mielczarek

Given a homological epimorphism $\pi:\mathcal{C}\longrightarrow \mathcal{C}/\mathcal{I}$ between $K$-categories, we show that if the ideal $\mathcal{I}$ satisfies certain conditions, then there exists an equivalence between the singularity…

Representation Theory · Mathematics 2025-10-14 Juan Andrés Orozco Gutiérrez , Valente Santiago Vargas

Let $G$ be a connected reductive affine algebraic group defined over the complex numbers, and $K\subset G$ be a maximal compact subgroup. Let $X , Y$ be irreducible smooth complex projective varieties and $f: X \rightarrow Y$ an algebraic…

Algebraic Geometry · Mathematics 2015-07-17 Indranil Biswas , Carlos Florentino

Given a discrete group $\Gamma=<g_1,\ldots,g_M>$ and a number $K\in\mathbb N$, a unitary representation $\rho:\Gamma\to U_K$ is called quasi-flat when the eigenvalues of each $\rho(g_i)\in U_K$ are uniformly distributed among the $K$-th…

Quantum Algebra · Mathematics 2019-07-24 Teodor Banica , Alexandru Chirvasitu

A Quillen model structure is presented by an interacting pair of weak factorization systems. We prove that in the world of locally presentable categories, any weak factorization system with accessible functorial factorizations can be lifted…

Category Theory · Mathematics 2022-05-23 Richard Garner , Magdalena Kedziorek , Emily Riehl

Let $G$ be a connected reductive group over an algebraically closed field $\Bbbk$. Under mild restrictions on the characteristic of $\Bbbk$, we show that any $G$-module with a good filtration also has a good filtration as a module for the…

Representation Theory · Mathematics 2021-06-09 Pramod N. Achar , William Hardesty

We formalize the concept of a centralizer-respecting homomorphism, surjective homomorphisms which are equivariant with respect to taking the centralizer of a subgroup. There is a functor from the category of centralizer-respecting…

Group Theory · Mathematics 2026-05-15 William Cocke , Mark L. Lewis , Ryan McCulloch

In a 2005 paper, Casacuberta, Scevenels and Smith construct a homotopy idempotent functor $E$ on the category of simplicial sets with the property that whether it can be expressed as localization with respect to a map $f$ is independent of…

Algebraic Topology · Mathematics 2024-05-29 J. Daniel Christensen

We give extensions of results on nonnegative matrix semigroups which deduce finiteness or boundedness of such semigroups from the corresponding local properties, e.g., from finiteness or boundedness of values of certain linear functionals…

Functional Analysis · Mathematics 2013-07-01 Roman Drnovšek , Heydar Radjavi