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We define the notion of an indexed profunctor over a 2-category, and use it to develop an abstract theory of limits. The theory subsumes (conical) limits, weighted limits, ends and Kan extensions. Results include an abstract version of the…

Category Theory · Mathematics 2023-02-14 Sori Lee

Internal categories feature notions of limit and completeness, as originally proposed in the context of the effective topos. This paper sets out the theory of internal completeness in a general context, spelling out the details of the…

Category Theory · Mathematics 2020-04-21 Enrico Ghiorzi

Categories are coreflectively embedded in multicategories via the "discrete cocone" construction, the right adjoint being given by the monoid construction. Furthermore, the adjunction lifts to the "cartesian level": preadditive categories…

Category Theory · Mathematics 2013-04-11 Claudio Pisani

A correspondence functor is a functor from the category of finite sets and correspondences to the category of k-modules, where k is a commu-tative ring. A main tool for this study is the construction of a correspondence functor associated…

Representation Theory · Mathematics 2019-02-15 Serge Bouc , Jacques Thévenaz

We study the notion of fundamental group in the framework of descent-exact homological categories. This setting is sufficiently wide to include several categories of "algebraic" nature such as the almost abelian categories, the semi-abelian…

Category Theory · Mathematics 2016-04-13 Mathieu Duckerts-Antoine

We observe that an enriched right adjoint functor between model categories which preserves acyclic fibrations and fibrant objects is quite generically a right Quillen functor.

Algebraic Topology · Mathematics 2024-06-05 Victor Carmona

This article is an introduction to the basic generalized category theory used in recent work on an extension of the theory of categories and categorical logic, including parts of topos theory. We discuss functors, equivalences, natural…

Category Theory · Mathematics 2017-12-27 Lucius T. Schoenbaum

We initiate the study of the cohomology of (strict polynomial) bifunctors by introducing the foundational formalism, establishing numerous properties in analogy with the cohomology of functors, and providing computational techniques. Since…

K-Theory and Homology · Mathematics 2008-05-19 Vincent Franjou , Eric M. Friedlander

Some basic features of the simultaneous inclusion of discrete fibrations and discrete opfibrations in categories over a base category X are considered. In particular, we illustrate the formulas (|P)x = ten(x/X,P) ; (P|)x = hom(X/x,P) which…

Category Theory · Mathematics 2007-05-23 Claudio Pisani

We describe simple criteria under which a given functor is naturally equivalent to an enriched one. We do this for several bases of enrichment, namely (pointed) simplicial sets, (pointed) topological spaces and orthogonal spectra. We also…

Algebraic Topology · Mathematics 2025-08-20 Thomas Blom

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 propose to define the notion of abstract local cohomology functors. The derived functors of the ordinary local cohomology functor with support in the closed subset defined by an ideal and the generalized local cohomology functor…

Commutative Algebra · Mathematics 2010-01-07 Yuji Yoshino , Takeshi Yoshizawa

For any additive functor from modules (or, more generally, from an abelian category with enough projectives or injectives), we construct long sequences tying up together the derived functors, the satellites, and the stabilizations of the…

Representation Theory · Mathematics 2025-04-30 Alex Martsinkovsky

We investigate functors between abelian categories having a left adjoint and a right adjoint that are \emph{similar} (these functors are called \emph{quasi-Frobenius functors}). We introduce the notion of a \emph{quasi-Frobenius bimodule}…

Rings and Algebras · Mathematics 2008-09-03 F. Castano Iglesias , C. Nastasescu , J. Vercruysse

The postulates of comprehension and extensionality in set theory are based on an inversion principle connecting set-theoretic abstraction and the property of having a member. An exactly analogous inversion principle connects functional…

Category Theory · Mathematics 2007-05-23 K. Dosen

We show in many cases the existence of adjoints to extension of scalars on categories of motivic nature, in the framework of field extensions. This is to be contrasted with the more classical situation where one deals with a finite type…

Algebraic Geometry · Mathematics 2020-06-04 Bruno Kahn

In this paper we provide a criterion of essential self-adjointness for operators in the tensor product of a separable Hilbert space and a Fock space. The class of operators we consider may contain a self-adjoint part, a part that preserves…

Functional Analysis · Mathematics 2015-02-12 Marco Falconi

Conceiving of premises as collected into sets or multisets, instead of sequences, may lead to triviality for classical and intuitionistic logic in general proof theory, where we investigate identity of deductions. Any two deductions with…

Logic · Mathematics 2016-06-10 Kosta Dosen

Some aspects of basic category theory are developed in a finitely complete category $\C$, endowed with two factorization systems which determine the same discrete objects and are linked by a simple reciprocal stability law. Resting on this…

Category Theory · Mathematics 2008-02-06 Claudio Pisani

We construct an explicit combinatorial model of the functor which adds right adjoints to the morphisms of an $\infty$-category, and we speculate on possible extensions to higher dimensions.

Category Theory · Mathematics 2025-10-08 Lorenzo Riva , Martina Rovelli