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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

In previous work, we introduce an axiomatic framework within which to prove theorems about many varieties of infinite-dimensional categories simultaneously. In this paper, we establish criteria implying that an $\infty$-category - for…

Category Theory · Mathematics 2020-07-17 Emily Riehl , Dominic Verity

The notion of a joint system, as captured by the monoidal (a.k.a. tensor) product, is fundamental to the compositional, process-theoretic approach to physical theories. Promonoidal categories generalise monoidal categories by replacing the…

Category Theory · Mathematics 2023-08-01 James Hefford , Aleks Kissinger

This paper develops a theory of colimit sketches "with constructions" in higher category theory, formalising the input to the ubiquitous procedure of adjoining specified "constructible" colimits to a category such that specified "relation"…

Category Theory · Mathematics 2021-11-25 Andrew W. Macpherson

Riehl and Shulman introduced simplicial type theory (STT), a variant of homotopy type theory which aimed to study not just homotopy theory, but its fusion with category theory: $(\infty,1)$-category theory. While notoriously technical,…

Logic in Computer Science · Computer Science 2025-12-12 Daniel Gratzer , Jonathan Weinberger , Ulrik Buchholtz

In this note we describe conditions under which the algebras for a monad on a presheaf category equipped with some additional structure are fibrant objects in a model structure. We also prove that when these conditions are satisfied the…

Algebraic Topology · Mathematics 2013-02-08 Michael A. Warren

We develop a number of basic concepts in the theory of categories internal to an $\infty$-topos. We discuss adjunctions, limits and colimits as well as Kan extensions for internal categories, and we use these results to prove the universal…

Category Theory · Mathematics 2024-02-14 Louis Martini , Sebastian Wolf

Cosheaves are a dual notion of sheaves. In this paper, we prove existence of a dual of sheafifications, called \textit{cosheafifications}, in the $\infty$-category theory. We also prove that the $\infty$-category of $\infty$-cosheaves is…

Category Theory · Mathematics 2021-12-16 Yuri Shimizu

We make Hinich's $\infty$-categorical enriched Yoneda embedding natural. To do so, we exhibit it as the unit of a partial adjunction between the functor taking enriched presheaves and Heine's functor taking a tensored category to an…

Category Theory · Mathematics 2024-07-09 Shay Ben-Moshe

For $\Lambda$ the category of free opetopic algebras, we construct a model structure \emph{\`a la Cisinski} on the category of presheaves over $\Lambda$, and show that is is equivalent to opetopic complete Segal spaces. This generalizes the…

Category Theory · Mathematics 2020-01-23 Cédric Ho Thanh , Chaitanya Leena Subramaniam

We study (vertically) normal lax double functors valued in the weak double category $\mathbb{C}\mathrm{at}$ of small categories, functors, profunctors and natural transformations, which we refer to as lax double presheaves. We show that for…

Category Theory · Mathematics 2024-10-29 Benedikt Fröhlich , Lyne Moser

It is proved that for any Grothendieck site $X$, there exists a coreflection (called $\mathbf{cosheafification}$) from the category of precosheaves on $X$ with values in a category $\mathbf{K}$, to the full subcategory of cosheaves,…

Category Theory · Mathematics 2016-05-06 Andrei V. Prasolov

This paper makes contributions to ``pure'' sheaf model theory, the part of model theory in which the models are sheaves over a complete Heyting algebra. We start by outlining the theory in a way we hope is readable for the non-specialist.…

Logic · Mathematics 2026-02-10 Andreas Brunner , Charles Morgan , Darllan Conceição Pinto

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

We prove that the projective model structure on the category of unbounded cochain complexes extends naturally to the category of contractions. The proof is completely elementary and we do not assume familiarity with model categories.

Algebraic Topology · Mathematics 2017-03-10 Marco Manetti , Chiara Spagnoli

We state a Yoneda-type lemma which leads to various functor categories being compact closed.

Category Theory · Mathematics 2007-05-23 Brian J. Day

Presheaves and nominal sets provide alternative abstract models of sets of syntactic objects with free and bound variables, such as lambda-terms. One distinguishing feature of the presheaf-based perspective is its elegant syntax-free…

Logic in Computer Science · Computer Science 2026-02-13 Fabian Lenke , Stefan Milius , Henning Urbat

Given a graded monoid A with 1, one can construct a projective monoid scheme MProj(A) analogous to Proj(R) of a graded ring R. This paper is concerned with the study of quasicoherent sheaves (of pointed sets) on MProj(A), and we prove…

Algebraic Geometry · Mathematics 2016-02-18 Oliver Lorscheid , Matt Szczesny

We collect in one place a variety of known and folklore results in enriched model category theory and add a few new twists. The central theme is a general procedure for constructing a Quillen adjunction, often a Quillen equivalence, between…

Algebraic Topology · Mathematics 2017-09-01 Bertrand Guillou , J. P. May

Notions and techniques of enriched category theory can be used to study topological structures, like metric spaces, topological spaces and approach spaces, in the context of topological theories. Recently in [D. Hofmann, Injective spaces…

Category Theory · Mathematics 2008-07-28 Maria Manuel Clementino , Dirk Hofmann