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Related papers: Elementary $\infty$-toposes from type theory

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Using dependent type theory to formalise the syntax of dependent type theory is a very active topic of study and goes under the name of "type theory eating itself" or "type theory in type theory." Most approaches are at least loosely based…

Logic in Computer Science · Computer Science 2021-02-02 Nicolai Kraus

We introduce and develop the model-theoretic notions of absolute connectedness and type-absolute connectedness for groups. We prove that groups of rational points of split semisimple linear groups (that is, Chevalley groups) over arbitrary…

Group Theory · Mathematics 2012-09-10 Jakub Gismatullin

We present the first definition of strictly associative and unital $\infty$-category. Our proposal takes the form of a type theory whose terms describe the operations of such structures, and whose definitional equality relation enforces…

Category Theory · Mathematics 2024-07-08 Eric Finster , Alex Rice , Jamie Vicary

We identify the obstructions for the functoriality and the uniqueness of the totalization functor, (partially) defined on the category of simplicial objects in the homotopy category of a stable model category, and we use a result from the…

Algebraic Topology · Mathematics 2014-10-01 Crichton Ogle , Andrew Salch

In this article we consider the homotopy theory of stratified spaces through a simplicial point of view. We first consider a model category of filtered simplicial sets over some fixed poset $P$, and show that it is a simplicial…

Algebraic Topology · Mathematics 2020-03-24 Sylvain Douteau

We construct classifying $\infty$-topoi by showing that the $(\infty,2)$-category of topoi has weighted limits. We show that several prestacks of interest have a classifying topos, including the prestack of spectra.

Category Theory · Mathematics 2026-01-29 Ivan Di Liberti , Nicholas Meadows

Most categorical models for dependent types have traditionally been heavily set based: contexts form a category, and for each we have a set of types in said context -- and for each type a set of terms of said type. This is the case for…

Logic in Computer Science · Computer Science 2023-12-25 Greta Coraglia , Jacopo Emmenegger

$\infty$-category theory was originally developed in the context of classical homotopy theory using standard set theoretical assumptions, but has since been extended to a variety of mathematical foundations. One such successful effort,…

Category Theory · Mathematics 2025-08-13 Nima Rasekh

We develop a homotopy theory of categories enriched in a monoidal model category V. In particular, we deal with homotopy weighted limits and colimits, and homotopy local presentability. The main result, which was known for…

Category Theory · Mathematics 2019-07-08 Stephen Lack , Jiri Rosicky

We present a new coherence theorem for comprehension categories, providing strict models of dependent type theory with all standard constructors, including dependent products, dependent sums, identity types, and other inductive types.…

Logic · Mathematics 2016-04-20 Peter LeFanu Lumsdaine , Michael A. Warren

Let $\mathcal A$ be a Hom-finite abelian category with enough projectives. In this note, we show that any covariantly finite $\tau$-rigid subcategory is contained in a support $\tau$-tilting subcategory. We also show that support…

Representation Theory · Mathematics 2023-02-07 Yu Liu , Panyue Zhou

A groupoid is a small category in which each morphism has an inverse. A topological groupoid is a groupoid in which both sets of objects and morphisms have topologies such that all groupoid structure maps are continuous. The notion of…

Differential Geometry · Mathematics 2007-05-23 Osman Mucuk , Ilhan Icen

We introduce the notion of an EILC topos: a topos $\mathcal{E}$ such that every essential geometric morphism with codomain $\mathcal{E}$ is locally connected. We then show that the topos of sheaves on a topological space $X$ is EILC if $X$…

Category Theory · Mathematics 2022-04-07 Jens Hemelaer

We propose an abstract notion of a type theory to unify the semantics of various type theories including Martin-L\"{o}f type theory, two-level type theory and cubical type theory. We establish basic results in the semantics of type theory:…

Category Theory · Mathematics 2023-08-10 Taichi Uemura

Let $\mathsf{KP}$ denote Kripke-Platek Set Theory and let $\mathsf{M}$ be the weak set theory obtained from $\mathsf{ZF}$ by removing the collection scheme, restricting separation to $\Delta_0$-formulae and adding an axiom asserting that…

Logic · Mathematics 2025-08-28 Zachiri McKenzie

We formulate a model-independent theory of co/cartesian morphisms and co/cartesian fibrations: that is, one which resides entirely *within the $\infty$-category of $\infty$-categories*. We prove this is suitably compatible with the…

Category Theory · Mathematics 2015-10-09 Aaron Mazel-Gee

The invertibility hypothesis for a monoidal model category S asks that localizing an S-enriched category with respect to an equivalence results in an weakly equivalent enriched category. This is the most technical among the axioms for S to…

Algebraic Topology · Mathematics 2016-02-18 Tyler Lawson

We prove that the category of generalized holomorphically contractible families possesses maximal and minimal objects. Moreover, we present basic properties of these extremal families.

Complex Variables · Mathematics 2007-05-23 Marek Jarnicki , Witold Jarnicki , Peter Pflug

The goal of this article is to develop the theory of presentable categories and topoi internal to an arbitrary $\infty$-topos $\mathcal{B}$. Our main results are internal analogues of Lurie's and Lurie-Simpson's characterisations of…

Category Theory · Mathematics 2025-03-25 Louis Martini , Sebastian Wolf

We give an elementary description of $2$-categories $\mathbf{Cat}\left(\mathcal{E}\right)$ of internal categories, functors and natural transformations, where $\mathcal{E}$ is a category modelling Lawvere's elementary theory of the category…

Category Theory · Mathematics 2025-03-26 Calum Hughes , Adrian Miranda