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We construct for every proper algebraic space over a ground field an Albanese map to a para-abelian variety, which is unique up to unique isomorphism. This holds in the absence of rational points or ample sheaves, and also for reducible or…

Algebraic Geometry · Mathematics 2023-11-10 Bruno Laurent , Stefan Schröer

A construction of the noncommutative-geometric counterparts of classical classifying spaces is presented, for general compact matrix quantum structure groups. A quantum analogue of the classical concept of the classifying map is introduced…

q-alg · Mathematics 2008-02-03 Mico Durdevic

We introduce local invariants of algebraic spaces and stacks which measure how far they are from being a scheme. Using these invariants, we develop mostly topological criteria to determine when the moduli space of a stack is a scheme. As an…

Algebraic Geometry · Mathematics 2024-11-12 Andres Fernandez Herrero , Dario Weißmann , Xucheng Zhang

In this paper, Lusternik-Schinrelmann and geometric category of finite spaces are considered. We define new numerical invariants of these spaces derived from the geometric category and present an algorithmic approach for its effective…

Algebraic Topology · Mathematics 2022-09-30 Manuel Cárdenas , Ramón Flores , Antonio Quintero , Maria Trinidad Villar-Liñán

Let $A$ be an $n$-dimensional algebra over a field $k$ and $a(A)$ its quantum symmetry semigroup. We prove that the automorphisms group ${\rm Aut}_{\rm Alg} (A)$ of $A$ is isomorphic to the group $U \bigl( G(a (A)^{\rm o} ) \bigl)$ of all…

Rings and Algebras · Mathematics 2022-03-28 G. Militaru

We show that the K-theory cosheaf is a complete invariant for separable continuous fields with vanishing boundary maps over a finite-dimensional compact metrizable topological space whose fibers are stable Kirchberg algebras with rational…

Operator Algebras · Mathematics 2014-02-12 Rasmus Bentmann

A generalization of the Pistone-Sempi argument, demonstrating the utility of non-commutative Orlicz spaces, is presented. The question of lifting positive maps defined on von Neumann algebra to maps on corresponding noncommutative Orlicz…

Operator Algebras · Mathematics 2025-03-19 Louis E. Labuschagne , Wladyslaw A. Majewski

Absolute algebras are a new type of algebraic structures, endowed with a meaningful notion of infinite sums of operations without supposing any underlying topology. Opposite to the usual definition of operadic calculus, they are defined as…

Algebraic Topology · Mathematics 2025-05-08 Victor Roca i Lucio

We prove a noncommutative variant of Saskin's classical theorem -- on the connection between Choquet boundaries for function spaces and Korovkin sets -- for operator systems generating separable Type I C*-algebras. The main result implies…

Operator Algebras · Mathematics 2015-05-22 Craig Kleski

According to the basic idea of category theory, any Einstein algebra, essentially an algebraic formulation of general relativity, can be considered from the point of view of any object of the category of smooth algebras; such an object is…

Mathematical Physics · Physics 2022-10-26 Leszek Pysiak , Wiesław Sasin , Michael Heller , Tomasz Miller

A new category of topological spaces with additional structures, called m-towers, is introduced. It is shown that there is a covariant functor which establishes a one-to-one correspondences between unital (resp. arbitrary) subhomogeneous…

Operator Algebras · Mathematics 2013-10-22 Piotr Niemiec

We introduce Liu algebras as Banach algebras which are 'locally affinoid', and define non-Archimedean Stein algebras as suitable inverse limits of these. We show that this gives rise to a complete functorial characterisation of…

Algebraic Geometry · Mathematics 2025-12-02 Tom Biesbrouck

We introduce rigid algebras, a generalization of rigid categories to arbitrary symmetric monoidal $(\infty,2)$-categories. We develop their general theory, showing in particular that the a priori $(\infty,2)$-category of rigid algebras is…

Category Theory · Mathematics 2026-05-25 Leor Neuhauser

We prove a complex version of Kostant's non-linear convexity theorem. Applications to the construction of G-invariant Grauert tubes of non-compact Riemannian symmetric G/K spaces are given.

Representation Theory · Mathematics 2007-05-23 Simon Gindikin , Bernhard Kroetz

A natural extension of the Hopf-cyclic cohomology, with coefficients, is introduced to encompass topological Hopf algebras. The topological theory allows to work with infinite dimensional Lie algebras. Furthermore, the category of…

K-Theory and Homology · Mathematics 2018-07-30 Bahram Rangipour , Serkan Sütlü

We provide a direct and elementary proof of the fact that the category of Nachbin's compact ordered spaces is dually equivalent to an Aleph_1-ary variety of algebras. Further, we show that Aleph_1 is a sharp bound: compact ordered spaces…

Category Theory · Mathematics 2020-11-19 Marco Abbadini , Luca Reggio

We show how the $\tau$-cluster morphism category may be defined in terms of the wall-and-chamber structure of an algebra. This geometric perspective leads to a simplified proof that the category is well-defined.

Representation Theory · Mathematics 2023-04-20 Sibylle Schroll , Aran Tattar , Hipolito Treffinger , Nicholas J. Williams

We study the problem of existence and uniqueness of homotopy colimits in stable representation theory, where one typically does not have model category structures to guarantee that these homotopy colimits exist or have good properties. We…

Algebraic Topology · Mathematics 2013-03-18 A. Salch

The paper is a survey of recent results in geometric representation theory describing group actions which induce multiplicity-free representations in the spaces of holomorphic functions. For connected compact Lie groups of automorphisms of…

Representation Theory · Mathematics 2012-03-05 Dmitri Akhiezer

In arXiv:math/0606241v2 M. Kontsevich and Y. Soibelman argue that the category of noncommutative (thin) schemes is equivalent to the category of coalgebras. We propose that under this correspondence the affine scheme of a k-algebra A is the…

Rings and Algebras · Mathematics 2008-05-16 Lieven Le Bruyn