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The behaviour of limits of weak morphisms in 2-dimensional universal algebra is not 2-categorical in that, to fully express the behaviour that occurs, one needs to be able to quantify over strict morphisms amongst the weaker kinds.…

Category Theory · Mathematics 2022-01-31 John Bourke

We construct a finitary additive 2-category whose Grothendieck ring is isomorphic to the semigroup algebra of the monoid of order-decreasing and order-preserving transformations of a finite chain.

Representation Theory · Mathematics 2017-05-10 Anna-Louise Grensing , Volodymyr Mazorchuk

We use the general notion of 2-dimensional adjunction with given coherence equations as introduced by MacDonald-Stone, building on earlier work by Gray, to derive coherence equations for a general 2-monad, which we refer to as a lax-Gray…

Category Theory · Mathematics 2021-03-04 John Lauchlin MacDonald , Laura Scull

We study thick subcategories of the category of 2-term complexes of projective modules over an associative algebra. We show that those thick subcategories that have enough injectives are in explicit bijection with 2-term silting complexes…

Representation Theory · Mathematics 2023-08-23 Monica Garcia

In this survey paper we give account of several approaches to the strictification and non-strictification of monoidal categories, which are constructions that turn a monoidal category into a (non-)strict one monoidally equivalent to the…

Category Theory · Mathematics 2024-12-31 Jorge Becerra

This is a collection of introductory, expository notes on applied category theory, inspired by the 2018 Applied Category Theory Workshop, and in these notes we take a leisurely stroll through two themes (functorial semantics and…

Category Theory · Mathematics 2018-10-05 Tai-Danae Bradley

The Eilenberg-Moore constructions and a Beck-type theorem for pairs of monads are described. More specifically, a notion of a {\em Morita context} comprising of two monads, two bialgebra functors and two connecting maps is introduced. It is…

Category Theory · Mathematics 2009-09-22 Tomasz Brzeziński , Adrian Vazquez Marquez , Joost Vercruysse

In this paper we explain the relationship between Frobenius objects in monoidal categories and adjunctions in 2-categories. In particular, we show that every Frobenius object in a monoidal category M arises from an ambijunction…

Category Theory · Mathematics 2010-06-07 Aaron D. Lauda

We make precise the structure of the first two reduction morphisms associated with codimension two nonsingular subvarieties of quadrics $\Q{n}$, $n\geq 5$. We give a coarse classification of the same class of subvarieties when they are…

alg-geom · Mathematics 2008-02-03 Mark Andrea A. de Cataldo

The Morita context provided by an exact module category over a finite tensor category gives a two-object bicategory with duals. Right and left duals of objects in the module category are given by internal Homs and coHoms, respectively. We…

Quantum Algebra · Mathematics 2023-10-19 Jürgen Fuchs , César Galindo , David Jaklitsch , Christoph Schweigert

For every adjunction of stable $\infty$-categories -- or more generally, in any locally stable $(\infty,2)$-category -- we give a simple procedure for inverting the twist and cotwist functors associated to this adjunction. As a consequence,…

Category Theory · Mathematics 2026-05-15 Fernando Abellán , Jonte Gödicke

For any graded commutative noetherian ring, where the grading group is abelian and where commutativity is allowed to hold in a quite general sense, we establish an inclusion-preserving bijection between, on the one hand, the twist-closed…

Category Theory · Mathematics 2012-11-07 Ivo Dell'Ambrogio , Greg Stevenson

This note relates axioms for partial semigroups and monoids with those for small object-free categories, either with multiple monoidal units or with source and target maps. We discuss the adjunction of a zero element to both kinds of…

Logic in Computer Science · Computer Science 2020-02-03 James Cranch , Simon Doherty , Georg Struth

We describe a 2-dimensional analogue of track categories, called two-track categories, and show that it can be used to model categories enriched in 2-type mapping spaces. We also define a Baues-Wirsching type cohomology theory for track…

Algebraic Topology · Mathematics 2010-02-18 David Blanc , Simona Paoli

We extend Morita theory to abelian categories by using wide Morita contexts. Several equivalence results are given for wide Morita contexts between abelian categories, widely extending equivalence theorems for categories of modules and…

Rings and Algebras · Mathematics 2007-05-23 N. Chifan , S. Dascalescu , C. Nastasescu

The Fourier-Mukai transform is lifted to the derived category of sheaves with connection on abelian varieties. The case of flat connections (D-modules) is discussed in detail.

alg-geom · Mathematics 2008-02-03 Mitchell Rothstein

Everyone knows that if you have a bivariant homology theory satisfying a base change formula, you get an representation of a category of correspondences. For theories in which the covariant and contravariant transfer maps are in mutual…

Category Theory · Mathematics 2022-12-21 Andrew W. Macpherson

We provide an explicit and elementary construction of the Morita $(\infty,2)$-category of a monoidal category which satisfies minimal conditions. We construct it as a $3$-coskeletal $2$-complicial set, in which the vertices encode the…

Category Theory · Mathematics 2025-09-29 Arghan Dutta , Stefano Luneia , Martina Rovelli , Sam Silver

We consider the localisation of the 2-category of diffeological groupoids at weak equivalences from the perspective of anafunctors, and with this language, prove that the localisation of the 2-category of Lie groupoids is an essentially…

Differential Geometry · Mathematics 2026-01-29 Jordan Watts

It is known that the so-called monadic decomposition, applied to the adjunction connecting the category of bialgebras to the category of vector spaces via the tensor and the primitive functors, returns the usual adjunction between…

Category Theory · Mathematics 2021-02-15 Alessandro Ardizzoni , Claudia Menini