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Related papers: Universality of Barwick's unfurling construction

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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 prove a universal property for $\infty$-categories of spans in the generality of Barwick's adequate triples, explicitly describe the cocartesian fibration corresponding to the span functor, and show that the latter restricts to a…

Category Theory · Mathematics 2023-09-21 Rune Haugseng , Fabian Hebestreit , Sil Linskens , Joost Nuiten

Structures where we have both a contravariant (pullback) and a covariant (pushforward) functoriality that satisfy base change can be encoded by functors out of ($\infty$-)categories of spans (or correspondences). In this paper we study the…

Category Theory · Mathematics 2021-11-30 Elden Elmanto , Rune Haugseng

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 provide, among other things: (i) a Bousfield--Kan formula for colimits in $\infty$-categories (generalizing the 1-categorical formula for a colimit as a coequalizer of maps between coproducts); (ii) $\infty$-categorical generalizations…

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

We study the left adjoint $\mathbb{D}$ to the forgetful functor from the $\infty$-category of symmetric monoidal $\infty$-categories with duals and finite colimits to the $\infty$-category of symmetric monoidal $\infty$-categories with…

Category Theory · Mathematics 2023-02-09 Tim Campion

We derive a new sufficient condition for the existence of {\omega}-categorical universal structures in classes of relational structures with constraints, augmenting results by Cherlin, Shelah, Chi, and Hubi\v{c}ka and Ne\v{s}et\v{r}il.…

Logic · Mathematics 2012-03-29 Christian Pech , Maja Pech

Using a categorial version of Fra\"iss\'e's theorem due to Droste and G\"obel, we derive a criterion for a comma-category to have universal homogeneous objects. As a first application we give new existence result for universal structures…

Category Theory · Mathematics 2013-02-26 Christian Pech , Maja Pech

It is well known that any model for derived manifolds must form a higher category. In this paper, we propose a universal property for this higher category, classifying it up to equivalence. Namely, the $\infty$-category $\mathbf{DMfd}$ of…

Algebraic Topology · Mathematics 2019-05-16 David Carchedi , Pelle Steffens

Semiadditivity of an $\infty$-category, i.e. the existence of biproducts, provides it with useful algebraic structure in the form of a canonical enrichment in commutative monoids. This ultimately comes from the fact that the…

Algebraic Topology · Mathematics 2025-05-26 Bastiaan Cnossen , Tobias Lenz , Sil Linskens

This paper unifies problems and results related to (embedding) universal and homomorphism universal structures. On the one side we give a new combinatorial proof of the existence of universal objects for homomorphism defined classes of…

Combinatorics · Mathematics 2014-06-11 Jan Hubička , Jaroslav Nešetřil

Given a representation of a C*-algebra, thought of as an abstract collection of physical observables, together with a unit vector, one obtains a state on the algebra via restriction. We show that the Gelfand-Naimark-Segal (GNS) construction…

Mathematical Physics · Physics 2018-03-28 Arthur J. Parzygnat

Let $M$ be a complex manifold, $D\subset M$ a free divisor and $U=M\setminus D$ its complement. In this paper we study the characteristic cycle $\textup{CC}(\gamma\cdot \ind_U)$ of the restriction of a constructible function $\gamma$ on…

Algebraic Geometry · Mathematics 2025-09-30 Xia Liao , Xiping Zhang

We extend Barwick's and Haugseng's construction of the double $\infty$-category of spans in a pullback-complete $\infty$-category $\mathfrak{C}$ to more general shapes: for a large class of algebraic patterns $\mathfrak{P}$, we define a…

Category Theory · Mathematics 2025-12-01 David Kern

We relate the existence problem of universal objects to the properties of corresponding enriched categories (lifts or expansions). In particular, extending earlier results, we prove that for every (possibly infinite) regular set F of finite…

Combinatorics · Mathematics 2013-03-05 Jan Hubička , Jaroslav Nešetřil

We exhibit the symmetric monoidal $\infty$-category $\mathrm{GrCob}$ of graph cobordisms between spaces as a full $\infty$-subcategory of the $\infty$-category $\mathrm{Psh}(\mathrm{Gr})$ of presheaves over $\mathrm{Gr}$, where…

Algebraic Topology · Mathematics 2026-01-08 Andrea Bianchi , Adela Yiyu Zhang

We prove a universal property for the $(\infty, n)$-category of correspondences, generalizing and providing a new proof for the case $n = 2$ from [GR17]. We also provide conditions under which a functor out of a higher category of…

Algebraic Topology · Mathematics 2020-11-06 Germán Stefanich

In this paper we prove a general theorem showing the extension property for partial automorphisms (EPPA, also called the Hrushovski property) for classes of structures containing relations and unary functions, optionally equipped with a…

Combinatorics · Mathematics 2022-01-25 Jan Hubička , Matěj Konečný , Jaroslav Nešetřil

In this paper, we generalize the construction method of schemes to other algebraic categories, and show that the category of coherent schemes can be characterized by a universal property, if we fix the class of Grothendieck topology. Also,…

Algebraic Geometry · Mathematics 2012-06-12 Satoshi Takagi

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
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