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We investigate canonical factorizations of ordered functors of ordered groupoids through star-surjective functors. Our main construction is a quotient ordered groupoid, depending on an ordered version of the notion of normal subgroupoid,…

Group Theory · Mathematics 2014-03-28 Nouf AlYamani , N. D. Gilbert , E. C. Miller

Given an $\infty$-category $C$ equipped with suitable wide subcategories $I, P \subset E\subset C$, we show that the $(\infty,2)$-category $\text{S}{\scriptstyle\text{PAN}}_2(C,E)_{P,I}$ of higher (or iterated) spans defined by Haugseng has…

Category Theory · Mathematics 2026-03-26 Bastiaan Cnossen , Tobias Lenz , Sil Linskens

We present general techniques for constructing functorial factorizations appropriate for model structures that are not known to be cofibrantly generated. Our methods use "algebraic" characterizations of fibrations to produce factorizations…

Algebraic Topology · Mathematics 2013-04-24 Tobias Barthel , Emily Riehl

We show that factorization systems, both strict and orthogonal, can be equivalently described as double categories satisfying certain properties. This provides conceptual reasons for why the category of sets and partial maps or the category…

Category Theory · Mathematics 2023-06-13 Miloslav Štěpán

In this note, we discuss several aspects of the functoriality of universal abelian factorizations associated to representations of quivers into abelian categories. After recalling the general construction of universal abelian…

Category Theory · Mathematics 2024-01-25 Luca Terenzi

The familiar construction of categories of fractions, due to Gabriel and Zisman, allows one to invert a class W of arrows in a category in a universal way. Similarly, bicategories of fractions allow one to invert a collection of arrows in a…

Category Theory · Mathematics 2013-03-05 Dorette A. Pronk , Michael A. Warren

In this article we introduce four variance flavours of cartesian 2-fibrations of $\infty$-bicategories with $\infty$-bicategorical fibres, in the framework of scaled simplicial sets. Given a map $p\colon \mathcal{E} \rightarrow\mathcal{B}$…

Category Theory · Mathematics 2025-01-01 Andrea Gagna , Yonatan Harpaz , Edoardo Lanari

We define strict and lax orthogonal factorization systems on double categories. These consist of an orthogonal factorization system on arrows and one on double cells that are compatible with each other. Our definitions are motivated by…

We establish the universal properties of the bicategory of polynomials, considering both cartesian and general morphisms between these polynomials. A direct proof of these universal properties would be impractical due to the complicated…

Category Theory · Mathematics 2018-12-27 Charles Walker

We prove that the derived category of a branched double cover is equivalent to a category of matrix factorizations for a fiberwise quadratic potential on the associated line bundle. This requires the linear fiber coordinate to have odd…

Algebraic Geometry · Mathematics 2026-05-28 Calum Crossley

We relativise double categories of relations to stable orthogonal factorisation systems. Furthermore, we present the characterisation of the relative double categories of relations in two ways. The first utilises a generalised comprehension…

Category Theory · Mathematics 2025-01-24 Keisuke Hoshino , Hayato Nasu

We construct a flagged $\infty$-category ${\sf Corr}$ of $\infty$-categories and bimodules among them. We prove that ${\sf Corr}$ classifies exponentiable fibrations. This representability of exponentiable fibrations extends that…

Category Theory · Mathematics 2020-06-25 David Ayala , John Francis

We define a natural 2-categorical structure on the base category of a large class of Grothendieck fibrations. Given any model category $\mathbf{C}$, we apply this construction to a fibration whose fibers are the homotopy categories of the…

Category Theory · Mathematics 2022-02-24 Joseph Helfer

We develop various aspects of the theory of recollements of $\infty$-categories, including a symmetric monoidal refinement of the theory. Our main result establishes a formula for the gluing functor of a recollement on the right-lax limit…

Algebraic Topology · Mathematics 2026-05-06 Jay Shah

We provide a short and reasonably self-contained proof of Lurie's straightening equivalence, relating cartesian fibrations over a given $\infty$-category $S$ with contravariant functors from $S$ to the $\infty$-category of small…

Category Theory · Mathematics 2024-12-23 Fabian Hebestreit , Gijs Heuts , Jaco Ruit

The principal aim of this note is to give an elementary proof of the fact that any two fiber functors of a Tannakian category are locally isomorphic. This builds on an idea of Deligne concerning scalar extensions of Tannakian categories and…

Algebraic Geometry · Mathematics 2018-05-10 Daniel Schäppi

We provide an $(\infty,n)$-categorical version of the straightening-unstraightening construction, asserting an equivalence between the $(\infty,n)$-category of double $(\infty,n-1)$-right fibrations over an $(\infty,n)$-category…

Algebraic Topology · Mathematics 2023-07-17 Lyne Moser , Nima Rasekh , Martina Rovelli

We present an efficient and user-friendly method for constructing any cofibrantly generated model structure on the category of double categories whose trivial fibrations are the "canonical" ones: the double functors which are surjective on…

Algebraic Topology · Mathematics 2025-09-30 Lyne Moser , Maru Sarazola , Paula Verdugo

We introduce unary operadic 2-categories as a framework for operadic Grothendieck construction for categorical $\mathbb{O}$-operads, $\mathbb{O}$ being a unary operadic category. The construction is a fully faithful functor…

Category Theory · Mathematics 2024-10-08 Dominik Trnka

We use the complete Segal approach to the theory of Cartesian fibrations to define and study representable Cartesian fibrations, generalizing representable right fibrations which have played a key role in $\infty$-category theory. In…

Category Theory · Mathematics 2021-02-12 Nima Rasekh