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This paper explores the interplay between category theory, topology, and the algebraic theory of finite groups. Our analysis unfolds in three stages. First, we establish the foundational universe of our objects: the complete and cocomplete…

Category Theory · Mathematics 2026-03-02 Ismael Gutierrez Garcia , Luz Adriana Mejía Castaño

It is well known that all torsors under an affine algebraic group over an algebraically closed field are trivial. We note that under suitable conditions this also holds if the the group is not necessarily of finite type. This has an…

Group Theory · Mathematics 2013-04-24 C. Deninger

The purpose of this article is threefold: Firstly, we propose some enhancements to the existing definition of 6-functor formalisms. Secondly, we systematically study the category of kernels, which is a certain 2-category attached to every…

Category Theory · Mathematics 2024-10-18 Claudius Heyer , Lucas Mann

We start by an original investigation on subgroups of (even infinite) direct sums in the first 4 sections, that largely generalizes Remak's known theorem; inspired by that general picture we have elsewhere extended this elementary "virtual"…

Group Theory · Mathematics 2017-08-31 Stephanos Gekas

In this paper we will prove that there exists a covariant functor from the category of schemes to the category of graphs. This functor provides a combination between algebraic varieties and combinatorial graphs so that the invariants…

Algebraic Geometry · Mathematics 2009-07-06 Feng-Wen An

Given a pair of adjoint functors between two arbitrary categories it induces mutually inverse equivalences between the full subcategories of the initial ones, consisting of objects for which the arrows of adjunction are isomorphisms. We…

Category Theory · Mathematics 2009-10-22 George Ciprian Modoi

A folklore result in category theory is that a (weakly) Cartesian closed category with finite co-products is distributive. Usually, the proof of this small result is carried on using the fact that the exponential functor is right adjoint to…

Category Theory · Mathematics 2014-06-16 Marco Benini

Let $G$ be a complex connected reductive algebraic group and let $G_{\mathbb{R}}$ be a real form of $G$. We construct a sequence of functors $L_i\mathcal{R}$ from admissible (resp. finite-length) representations of $G$ to admissible (resp.…

Representation Theory · Mathematics 2022-04-25 Lucas Mason-Brown

The article covers developments in the representation theory of finite group schemes over the last fifteen years. We start with the finite generation of cohomology of a finite group scheme and proceed to discuss various consequences and…

Representation Theory · Mathematics 2014-09-25 Julia Pevtsova

Category theory provides a collective description of many arrangements in mathematics, such as topological spaces, Banach spaces and game theory. Within this collective description, the perspective from any individual member of the…

Category Theory · Mathematics 2025-11-03 Suddhasattwa Das

The behaviour of limits of weak morphisms in 2-dimensional universal algebra is not 2-categorical in that, to fully express the behaviour that occurs, one needs to be able to quantify over strict morphisms amongst the weaker kinds.…

Category Theory · Mathematics 2022-01-31 John Bourke

In this paper we define a pair of faithful functors that map isomorphic and isotopic finite-dimensional algebras over finite fields to isomorphic graphs. These functors reduce the cost of computation that is usually required to determine…

Rings and Algebras · Mathematics 2017-02-08 O. J. Falcón , R. M. Falcón , J. Núñez , A. M. Pacheco , M. T. Villar

Translation association schemes are constructed from actions of finite groups on finite abelian groups satisfying certain natural conditions. It is also shown that the mere existence of maps from finite groups to themselves sending each…

Combinatorics · Mathematics 2011-08-26 Dae San Kim , Hyun Kwang Kim

The work is devoted to the extension groups in the category of functors from a small category to an additive category with an Abelian structure in the sense of Heller. It is constructed a spectral sequence which converges to the extension…

Category Theory · Mathematics 2009-09-28 A. A. Husainov , A. Pancar , M. Yapici

We show that taking the set of primitive idempotents of commutative association schemes is a functor from the category of commutative association schemes with surjective morphisms to the category of finite sets with surjective partial…

Combinatorics · Mathematics 2022-07-19 Makoto Matsumoto , Kento Ogawa , Takayuki Okuda

For a finite group scheme, the subadditive functions on finite dimensional representations are studied. It is shown that the projective variety of the cohomology ring can be recovered from the equivalence classes of subadditive functions.…

Representation Theory · Mathematics 2016-04-06 Dave Benson , Henning Krause

In the authors book, Associative Algebraic Geometry, 2023, and the following article Shemes of Associative Algebras,\\ https://doi.org/10.48550/arXiv.2410.17703,2024, we use an algebraization of the semi-local formal moduli of simple…

Algebraic Geometry · Mathematics 2025-11-06 Arvid Siqveland

Classical finite association schemes lead to a finite-dimensional algebras which are generated by finitely many stochastic matrices. Moreover, there exist associated finite hypergroups. The notion of classical discrete association schemes…

Group Theory · Mathematics 2019-05-21 Michael Voit

Thin coverings are a method of constructing graded-simple modules from simple (ungraded) modules. After a general discussion, we classify the thin coverings of (quasifinite) simple modules over associative algebras graded by finite abelian…

Representation Theory · Mathematics 2007-05-23 Yuly Billig , Michael Lau

We construct an iterative method for factorising small strict n-categories into a unique (up to isomorphism) collection of small 1- categories. Following this we develop the theory to include a large class of $\infty$-categories. We use…

Category Theory · Mathematics 2014-06-11 Scott Balchin