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Related papers: $(\infty,2)$-Topoi and descent

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In this work we provide a model-independent notion of local fibrations of $(\infty,2)$-categories which generalises the well-known theory of locally coCartesian fibrations of $(\infty,1)$-categories. Based on previous work, we construct a…

Algebraic Topology · Mathematics 2023-05-03 F. Abellán

We define an elementary $\infty$-topos that simultaneously generalizes an elementary topos and Grothendieck $\infty$-topos. We then prove it satisfies the expected topos theoretic properties, such as descent, local Cartesian closure,…

Category Theory · Mathematics 2022-01-11 Nima Rasekh

We develop some basic concepts in the theory of higher categories internal to an arbitrary $\infty$-topos. We define internal left and right fibrations and prove a version of the Grothendieck construction and of Yoneda's lemma for internal…

Category Theory · Mathematics 2022-04-04 Louis Martini

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 identify additional structure on a conservative lax monoidal functor from a closed monoidal category $\mathcal{C}$ to a Grothendieck-Verdier category $\mathcal{D}$, such that the Grothendieck-Verdier structure of $\mathcal{D}$ lifts to…

Category Theory · Mathematics 2026-01-22 Max Demirdilek

We introduce the notion of local fibration, a generalization of the notion of fibration which takes into account the presence of Grothendieck topologies on the two categories, and show that the classical results about fibrations lift to…

Category Theory · Mathematics 2025-07-22 Léo Bartoli , Olivia Caramello

A 2-categorical generalisation of elementary topos is provided and some of the properties of the yoneda structure it generates are explored. Examples relevant to the globular approach to higher category theory are discussed. This paper also…

Category Theory · Mathematics 2007-05-23 M. Weber

We develop the theory of topoi internal to an arbitrary $\infty$-topos $\mathcal B$. We provide several characterisations of these, including an internal analogue of Lurie's characterisation of $\infty$-topoi, but also a description in…

Category Theory · Mathematics 2025-03-19 Louis Martini , Sebastian Wolf

We prove the conjecture that any Grothendieck $(\infty,1)$-topos can be presented by a Quillen model category that interprets homotopy type theory with strict univalent universes. Thus, homotopy type theory can be used as a formal language…

Algebraic Topology · Mathematics 2019-04-30 Michael Shulman

Within the framework of Riehl-Shulman's synthetic $(\infty,1)$-category theory, we present a theory of two-sided cartesian fibrations. Central results are several characterizations of the two-sidedness condition \`{a} la Chevalley, Gray,…

Category Theory · Mathematics 2024-03-13 Jonathan Weinberger

We further develop Weber's notion of elementary 2-topos by proposing certain new axioms. We show that in a 2-category C satisfying these axioms, the "discrete opfibration (DOF) classifier" S is always an internal elementary 1-topos, in an…

Category Theory · Mathematics 2024-07-30 Joseph Helfer

We revisit the work of To\"en--Vezzosi and Lurie on Grothendieck topologies, using the new tools of acyclic classes and congruences. We introduce a notion of extended Grothendieck topology on any $\infty$-topos, and prove that the poset of…

Category Theory · Mathematics 2023-05-30 Mathieu Anel , Georg Biedermann , Eric Finster , André Joyal

This paper introduces and studies split two-sided 2-fibrations and locally discrete split two-sided 2-fibrations, using a formal categorical approach. We generalise Street's notion of split two-sided fibration internal to a 2-category to…

Category Theory · Mathematics 2026-02-11 Seerp Roald Koudenburg

In this work, we conclude our study of fibred $\infty$-bicategories by providing a Grothendieck construction in this setting. Given a scaled simplicial set $S$ (which need not be fibrant) we construct a 2-categorical version of Lurie's…

Algebraic Topology · Mathematics 2023-04-14 Fernando Abellán , Walker H. Stern

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

This is an introduction to Grothendieck's descent theory, with some stress on the general machinery of fibered categories and stacks.

Algebraic Geometry · Mathematics 2007-06-13 Angelo Vistoli

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

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 use Kan injectivity to axiomatise concepts in the 2-category of topoi. We showcase the expressivity of this language through many examples, and we establish some aspects of the formal theory of Kan extension in this 2-category (pointwise…

Logic · Mathematics 2025-05-22 Ivan Di Liberti , Lingyuan Ye

The Grothendieck construction establishes an equivalence between fibrations, a.k.a. fibred categories, and indexed categories, and is one of the fundamental results of category theory. Cockett and Cruttwell introduced the notion of…

Category Theory · Mathematics 2025-07-30 Marcello Lanfranchi
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