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We develop bicategory theory in univalent foundations. Guided by the notion of univalence for (1-)categories studied by Ahrens, Kapulkin, and Shulman, we define and study univalent bicategories. To construct examples of univalent…

Category Theory · Mathematics 2022-08-16 Benedikt Ahrens , Dan Frumin , Marco Maggesi , Niccolò Veltri , Niels van der Weide

We present a method of constructing monoidal, braided monoidal, and symmetric monoidal bicategories from corresponding types of monoidal double categories that satisfy a lifting condition. Many important monoidal bicategories arise…

Category Theory · Mathematics 2019-11-26 Linde Wester Hansen , Michael Shulman

Small B\'{e}nabou's bicategories and, in particular, Mac Lane's monoidal categories, have well-understood classifying spaces, which give geometric meaning to their cells. This paper contains some contributions to the study of the…

Category Theory · Mathematics 2013-09-18 M. Calvo , A. M. Cegarra , B. A. Heredia

In this article we investigate which categorical structures of a category C are inherited by its arrow category. In particular, we show that a monoidal equivalence between two categories gives rise to a monoidal equivalence between their…

Category Theory · Mathematics 2023-09-28 Paulina L. A. Goedicke , Jamie Vicary

We show that the categories of directed and undirected reflexive graphs carry exactly two (up to isomorphism) biclosed monoidal structures.

Combinatorics · Mathematics 2025-11-25 Adrien Grenier , Chris Kapulkin

We give an alternative presentation of braided monoidal categories. Instead of the usual associativity and braiding we have just one constraint (the b-structure). In the unital case, the coherence conditions for a b-structure are shown to…

Category Theory · Mathematics 2013-07-24 Alexei Davydov , Ingo Runkel

Just as knots and links can be algebraically described as certain morphisms in the category of tangles in 3 dimensions, compact surfaces smoothly embedded in R^4 can be described as certain 2-morphisms in the 2-category of `2-tangles in 4…

Quantum Algebra · Mathematics 2007-05-23 John C. Baez , Laurel Langford

We describe a perfect correspondence between skew monoidal categories and certain generalised multicategories, called skew multicategories, that arise in nature.

Category Theory · Mathematics 2019-07-08 John Bourke , Stephen Lack

This paper is a rather informal guide to some of the basic theory of 2-categories and bicategories, including notions of limit and colimit, 2-dimensional universal algebra, formal category theory, and nerves of bicategories. As is the way…

Category Theory · Mathematics 2010-09-10 Stephen Lack

We introduce the notion of a braiding on a skew monoidal category, whose curious feature is that the defining isomorphisms involve three objects rather than two. These braidings are shown to arise from, and classify, cobraidings (also known…

Category Theory · Mathematics 2020-01-29 John Bourke , Stephen Lack

We show that in any symmetric monoidal category, if a weight for colimits is absolute, then the resulting colimit of any diagram of dualizable objects is again dualizable. Moreover, in this case, if an endomorphism of the colimit is induced…

Category Theory · Mathematics 2014-07-01 Kate Ponto , Michael Shulman

We show that the bicategory of proper correspondences is the Dwyer-Kan localisation of the category of C*-algebras at a certain class of *-homomorphisms.

Operator Algebras · Mathematics 2026-03-27 Ralf Meyer

Actions of bicategories arise as categorification of actions of categories. They appear in a variety of different contexts in mathematics, from Moerdijk's classification of regular Lie groupoids in foliation theory, to Waldmann's work on…

Category Theory · Mathematics 2009-02-20 Igor Bakovic

We show that $\mathit{ann}$-categories admit a presentation by crossed bimodules, and prove that morphisms between them can be expressed by special kinds spans between the presentations. More precisely, we prove the groupoid of morphisms…

Category Theory · Mathematics 2015-10-08 Ettore Aldrovandi

Categories can be identified -- up to isomorphism -- with polynomial comonads on Set. The left Kan extension of a functor along itself is always a comonad -- called the density comonad -- so it defines a category when its carrier is…

Category Theory · Mathematics 2025-04-28 David I. Spivak

We treat the problem of lifting bicategories into double categories through categories of vertical morphisms. We make use of a specific instance of the Grothendieck construction to provide, for every bicategory equipped with a possible…

Category Theory · Mathematics 2019-10-30 Juan Orendain

Bicommutant categories are higher categorical analogs of von Neumann algebras that were recently introduced by the first author. In this article, we prove that every unitary fusion category gives an example of a bicommutant category. This…

Operator Algebras · Mathematics 2016-12-20 André Henriques , David Penneys

We describe a Cat-valued nerve of bicategories, which associates to every bicategory a simplicial object in Cat, called the 2-nerve. We define a 2-category NHom whose objects are bicategories and whose 1-cells are normal homomorphisms of…

Category Theory · Mathematics 2010-09-10 Stephen Lack , Simona Paoli

We start from any small strict monoidal braided Ab-category and extend it to a monoidal nonstrict braided Ab-category which contains braided bialgebras. The objects of the original category turn out to be modules for these bialgebras

Algebraic Topology · Mathematics 2010-07-02 Raul A. Perez , Carlos Prieto

2-stratifolds are a generalization of 2-manifolds in that there are disjoint simple closed curves where several sheets meet. They arise in the study of categorical invariants of 3-manifolds and may have applications to topological data…

Geometric Topology · Mathematics 2015-05-14 J. C. Gómez-Larrañaga , F. González-Acuña , Wolfgang Heil