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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

For our purposes, two functors {\Lambda} and {\Gamma} are said to be respectively left and right adjoints of each other if for any digraphs G and H, there exists a homomorphism of {\Lambda}(G) to H if and only if there exists a homomorphism…

Combinatorics · Mathematics 2015-06-04 Jan Foniok , Claude Tardif

Given an adjoint pair of functors $F,G$, the composite $GF$ naturally gets the structure of a monad. The same monad may arise from many such adjoint pairs of functors, however. Can one describe all of the adjunctions giving rise to a given…

Category Theory · Mathematics 2016-06-30 Andrew Salch

There are many contexts in algebraic geometry, algebraic topology, and homological algebra where one encounters a functor that has both a left and right adjoint, with the right adjoint being isomorphic to a shift of the left adjoint…

Algebraic Topology · Mathematics 2007-05-23 H. Fausk , P. Hu , J. P. May

In this paper we provided an explicit construction for the left adjoint of the forgetful functor from the category of Heyting algebras to that of Hilbert algebras. This functor factorizes through the free implicative semilattice extension…

Logic · Mathematics 2017-11-30 J. L. Castiglioni , H. J. San Martín

Every right adjoint functor between presentable $\infty$-categories is shown to decompose canonically as a coreflection, followed by, possibly transfinitely many, monadic functors. Furthermore, the coreflection part is given a presentation…

Algebraic Topology · Mathematics 2021-11-23 Lior Yanovski

We give another proof of the fact that there is a dual equivalence between the $\infty$-category of monoidal $\infty$-categories with left adjoint oplax monoidal functors and that with right adjoint lax monoidal functors by constructing a…

Category Theory · Mathematics 2023-02-07 Takeshi Torii

It is well-known in universal algebra that adding structure and equational axioms generates forgetful functors between varieties, and such functors all have left adjoints. The category of elementary doctrines provides a natural framework…

Category Theory · Mathematics 2024-05-14 Francesca Guffanti

We show that contrary to appearances, Multimodal Type Theory (MTT) over a 2-category M can be interpreted in any M-shaped diagram of categories having, and functors preserving, M-sized limits, without the need for extra left adjoints. This…

Category Theory · Mathematics 2024-02-14 Michael Shulman

The main result concerns a bicategorical factorization system on the bicategory $\mathrm{Cat}$ of categories and functors. Each functor $A\xra{f} B$ factors up to isomorphism as $A\xra{j}E\xra{p}B$ where $j$ is what we call an ultimate…

Category Theory · Mathematics 2021-04-08 Ross Street

In this paper we define a functor from the algebraic category of frontal Hilbert algebras to the algebraic category of frontal implicative semilattices which is left adjoint to the forgetful functor from the category of frontal implicative…

Logic · Mathematics 2018-11-12 Ramon Jansana , Hernan Javier San Martin

We present the notion of "cyclic double multicategory", as a structure in which to organise multivariable adjunctions and mates. The classic example of a 2-variable adjunction is the hom/tensor/cotensor trio of functors; we generalise this…

Category Theory · Mathematics 2012-08-24 Eugenia Cheng , Nick Gurski , Emily Riehl

We define a coherent adjunction in a strict $3$-category and we use string diagrams to show that any adjunction can be extended to a coherent adjunction in an essentially unique way.

Category Theory · Mathematics 2024-08-07 Manuel Araújo

We extend the basic concepts of Street's formal theory of monads from the setting of 2-categories to that of double categories. In particular, we introduce the double category Mnd(C) of monads in a double category C and define what it means…

Category Theory · Mathematics 2014-07-15 Thomas M. Fiore , Nicola Gambino , Joachim Kock

This note aims to introduce a left adjoint functor to the functor which assigns a heap to a group. The adjunction is monadic. It is explained how one can decompose a free group functor through the previously introduced adjoint and employ it…

Group Theory · Mathematics 2021-01-19 Bernard Rybołowicz

We develop a bicategorical setup in which one can speak about adjoint 1-morphisms even in the absence of genuine identity 1-morphisms. We also investigate which part of 2-representation theory of 2-categories extends to this new setup.

Category Theory · Mathematics 2020-03-11 Hankyung Ko , Volodymyr Mazorchuk , Xiaoting Zhang

Adjoint functor theorems give necessary and sufficient conditions for a functor to admit an adjoint. In this paper we prove general adjoint functor theorems for functors between $\infty$-categories. One of our main results is an…

Category Theory · Mathematics 2019-09-18 Hoang Kim Nguyen , George Raptis , Christoph Schrade

The bicategory of Landau-Ginzburg models denoted by LGK possesses adjoints and this helps in explaining a certain duality that exists in the setting of Landau-Ginzburg models in terms of some specified relations. The construction of LGK is…

Category Theory · Mathematics 2024-02-05 Yves Baudelaire Fomatati

Voevodsky's derived category of motives is the main arena today for the study of algebraic cycles and motivic cohomology. In this paper we study whether the inclusions of three important subcategories of motives have a left or right…

Algebraic Geometry · Mathematics 2016-03-30 Burt Totaro

We investigate adjoint and Frobenius pairs between categories of comodules over rather general corings. We particularize to the case of the adjoint pair of functors associated to a morphism of corings over different base rings, which leads…

Rings and Algebras · Mathematics 2007-05-23 M. Zarouali-Darkaoui