English
Related papers

Related papers: On pointwise Kan extensions in double categories

200 papers

In this article we develop formal category theory within augmented virtual double categories. Notably we formalise the classical notions of Kan extension, Yoneda embedding $\text y_A\colon A \to \hat A$, exact square, total category and…

Category Theory · Mathematics 2024-04-04 Seerp Roald Koudenburg

A notion of a coring extension is defined and it is related to the existence of an additive functor between comodule categories that factorises through forgetful functors. This correspondence between coring extensions and factorisable…

Rings and Algebras · Mathematics 2008-07-31 Tomasz Brzezinski

A double category of relations is essentially a cartesian equipment with strong, discrete and functorial tabulators and for which certain local products satisfy a Frobenius Law. A double category of relations is equivalent to a double…

Category Theory · Mathematics 2022-11-18 Michael Lambert

We prove a class of equivalences of additive functor categories that are relevant to enumerative combinatorics, representation theory, and homotopy theory. Let $\mathscr{X}$ denote an additive category with finite direct sums and split…

Category Theory · Mathematics 2019-04-01 Stephen Lack , Ross Street

Category theory is a branch of mathematics that provides a formal framework for understanding the relationship between mathematical structures. To this end, a category not only incorporates the data of the desired objects, but also…

Category Theory · Mathematics 2024-07-26 Niels van der Weide , Nima Rasekh , Benedikt Ahrens , Paige Randall North

Various models of $(\infty,1)$-categories, including quasi-categories, complete Segal spaces, Segal categories, and naturally marked simplicial sets can be considered as the objects of an $\infty$-cosmos. In a generic $\infty$-cosmos, whose…

Category Theory · Mathematics 2017-02-08 Emily Riehl , Dominic Verity

Under a general categorical procedure for the extension of dual equivalences as presented in this paper's predecessor, a new algebraically defined category is established that is dually equivalent to the category $\bf LKHaus$ of locally…

Category Theory · Mathematics 2021-09-16 G. Dimov , E. Ivanova-Dimova , W. Tholen

Many structured categories of interest are most naturally described as algebras for a relative monad, but turn out nonetheless to be algebras for an ordinary monad. We show that, under suitable hypotheses, the left oplax Kan extension of a…

Category Theory · Mathematics 2025-06-12 Umberto Tarantino , Joshua Wrigley

We systematically study the commutative factorization categories over the Ran space. We fill in what we consider as a gap in the construction of the factorizable Satake functor in the constructible setting in arXiv:1708.07205,…

Representation Theory · Mathematics 2026-05-22 Sergey Lysenko

The goal of this paper is to prove an equivalence between the $(\infty,2)$-category of cartesian factorization systems of $\infty$-categories and that of pointed cartesian fibrations of $\infty$-categories. This generalizes a similar result…

Algebraic Topology · Mathematics 2019-11-27 Edoardo Lanari

We introduce the notion of a definable category--a category equivalent to a full subcategory of a locally finitely presentable category that is closed under products, directed colimits and pure subobjects. Definable subcategories are…

Category Theory · Mathematics 2016-12-13 Amit Kuber , Jiří Rosický

We develop a self-dual, bivariant extension of the concept of an operadic category, its associated operads and their algebras. Our new theory covers, besides all classical subjects, also generalized traces and bivariant versions of…

Category Theory · Mathematics 2024-03-27 Martin Markl

We thoroughly treat several familiar and less familiar definitions and results concerning categories, functors and distributors enriched in a base quantaloid Q. In analogy with V-category theory we discuss such things as adjoint functors,…

Category Theory · Mathematics 2007-05-23 Isar Stubbe

We investigate an enriched-categorical approach to a field of discrete mathematics. The main result is a duality theorem between a class of enriched categories (called $\overline{\mathbb{Z}}$- or $\overline{\mathbb{R}}$-categories) and that…

Category Theory · Mathematics 2019-04-19 Soichiro Fujii

Products in double categories, as found in cartesian double categories, are an elegant concept with numerous applications, yet also have a few puzzling aspects. In this paper, we revisit double-categorical products from an unbiased…

Category Theory · Mathematics 2026-03-26 Evan Patterson

Some properties of the (normed) dual Hom-functor $D$ and its iterations $D^n$ are exhibited. For instance: $D$ turns every canonical embedding (in the second dual space) into a retraction (of the third dual onto the first one); $D$ rises…

Functional Analysis · Mathematics 2019-03-18 Nikica Uglesic

We prove that the fundamental group functor from categorical Galois theory may be computed as a Kan extension.

Category Theory · Mathematics 2014-04-07 Tomas Everaert , Julia Goedecke , Tim Van der Linden

In the first part of this paper we study fibrations of $(\infty,2)$-categories. We give a simple characterization of such fibrations in terms of a certain square being a pullback, and apply this to show that in some cases…

Category Theory · Mathematics 2026-02-10 Fernando Abellán , Rune Haugseng , Louis Martini

We define the notion of duality categories as generalization of duality groups. Two examples are treated. The first is the Serre duality in the categories of strict polynomial functors. The second concerns finite complexes. We show in…

Algebraic Topology · Mathematics 2015-07-07 Ramzi Ksouri

We develop pivotal and spherical versions of graded extension theory. We define the corresponding analogues of Brauer-Picard $2$-categorical groups and realize them as fixed points of natural $\mathbb{Z}$ and $\mathbb{Z}/2\mathbb{Z}$…