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Related papers: Formalizing colimits in Cat

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We show that the quasicategory defined as the localization of the category of (simple) graphs at the class of A-homotopy equivalences does not admit colimits. In particular, we settle in the negative the question of whether the A-homotopy…

Combinatorics · Mathematics 2023-09-06 Daniel Carranza , Chris Kapulkin , Jinho Kim

We construct a left semi-model category of "marked strict $\infty$-categories" for which the fibrant objects are those whose marked arrows satisfy natural closure properties and are weakly invertible. The canonical model structure on strict…

Category Theory · Mathematics 2025-03-26 Simon Henry Felix Loubaton

For A a category with finite colimits, we show that the embedding of A into the category of arrows Arr(A) determined by the initial object is the completion of A under strong homotopy cokernels. The nullhomotopy structure of Arr(A) (needed…

Category Theory · Mathematics 2023-10-03 Enrico M. Vitale

We prove general adjoint functor theorems for weakly (co)complete $n$-categories. This class of $n$-categories includes the homotopy $n$-categories of (co)complete $\infty$-categories, so these $n$-categories do not admit all small…

Category Theory · Mathematics 2022-08-03 Hoang Kim Nguyen , George Raptis , Christoph Schrade

For any category ${\mathcal E}$ and monad $T$ thereon, we introduce the notion of $T$-simplicial object in ${\mathcal E}$. Any $T$-category in the sense of Burroni induces a $T$-simplicial object as its nerve. This nerve construction…

Category Theory · Mathematics 2026-03-13 Soichiro Fujii , Stephen Lack

In this paper, we introduce a cofibrant simplicial category that we call the free homotopy coherent adjunction and characterize its n-arrows using a graphical calculus that we develop here. The hom-spaces are appropriately fibrant, indeed…

Category Theory · Mathematics 2015-10-14 Emily Riehl , Dominic Verity

Category theory is the language of homological algebra, allowing us to state broadly applicable theorems and results without needing to specify the details for every instance of analogous objects. However, authors often stray from the realm…

General Mathematics · Mathematics 2025-02-04 Skyler Marks

We study the *homotopy theory* of $\infty$-categories enriched in the $\infty$-category $sS$ of simplicial spaces. That is, we consider $sS$-enriched $\infty$-categories as presentations of ordinary $\infty$-categories by means of a "local"…

Algebraic Topology · Mathematics 2015-10-15 Aaron Mazel-Gee

Associated to each small category $C$, there is a category of $C$-shaped diagrams of simplicial sets and an $\infty$-category of $NC$-shaped homotopy coherent diagrams of spaces. We present a functor which exhibits the latter as the…

Algebraic Topology · Mathematics 2022-08-01 Severin Bunk

We construct a compact closed category out of any symmetric monoidal category by freely adding adjoints to its objects. The morphisms of the completion are defined as string diagrams annotated by objects and morphisms from the original…

Category Theory · Mathematics 2022-01-24 Antonin Delpeuch

The subject of this paper is a nerve construction for bicategories introduced by Leinster, which defines a fully faithful functor from the category of bicategories and normal pseudofunctors to the category of presheaves over Joyal's…

Category Theory · Mathematics 2020-04-21 Alexander Campbell

Many definitions of weak and strict $\infty$-categories have been proposed. In this paper we present a definition for $\infty$-categories with strict associators, but which is otherwise fully weak. Our approach is based on the existing type…

Category Theory · Mathematics 2021-09-06 Eric Finster , Alex Rice , Jamie Vicary

The goal of this paper is to develop a theory of join and slices for strict $\infty$-categories. To any pair of strict $\infty$-categories, we associate a third one that we call their join. This operation is compatible with the usual join…

Category Theory · Mathematics 2020-09-25 Dimitri Ara , Georges Maltsiniotis

A generalization of the notion of an $\infty$-category is presented, allowing for ($\infty$-)cat(egorie)s that may have non-invertible higher morphisms.

Category Theory · Mathematics 2014-03-10 Daniel Gerigk

This paper is the second in a series of two papers about generalizing Quillen's Theorem A to strict $\infty$-categories. In the first one, we presented a proof of this Theorem A of a simplicial nature, direct but somewhat ad hoc. In the…

Algebraic Topology · Mathematics 2020-09-07 Dimitri Ara , Georges Maltsiniotis

For a category $\mathcal E$ with finite limits and well-behaved countable coproducts, we construct a model structure, called the effective model structure, on the category of simplicial objects in $\mathcal E$, generalising the Kan--Quillen…

Category Theory · Mathematics 2022-11-11 Nicola Gambino , Simon Henry , Christian Sattler , Karol Szumiło

We present a doctrinal approach to category theory, obtained by abstracting from the indexed inclusions (via discrete fibrations and opfibrations) of the left and of the right actions of X in Cat in categories over X. Namely, a "weak…

Category Theory · Mathematics 2010-03-30 Claudio Pisani

We show that for an extensive $1$-category $\mathcal{E}$ with pullbacks and pullback stable coequalisers in which the forgetful functor $\mathcal{U}: \mathbf{Cat}(\mathcal{E})_1 \to \mathbf{Gph}(\mathcal{E})$ has left adjoint, the…

Category Theory · Mathematics 2025-11-07 Calum Hughes , Adrian Miranda

We give a new criterion guaranteeing existence of model structures left-induced along a functor admitting both adjoints. This works under the hypothesis that the functor induces idempotent adjunctions at the homotopy category level. As an…

Category Theory · Mathematics 2022-10-25 Philip Hackney , Martina Rovelli

We define and discuss lax and weighted colimits of diagrams in $\infty$-categories and show that the coCartesian fibration associated to a functor is given by its lax colimit. A key ingredient, of independent interest, is a simple…

Category Theory · Mathematics 2020-11-03 David Gepner , Rune Haugseng , Thomas Nikolaus