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This note proposes a new method to complete a triangulated category, which is based on the notion of a Cauchy sequence. We apply this to categories of perfect complexes. It is shown that the bounded derived category of finitely presented…

Representation Theory · Mathematics 2019-10-31 Tobias Barthel , Bernhard Keller , Henning Krause

Let $\mathcal{C}$ be an additive category. The nilpotent category $\mathrm{Nil} (\mathcal{C})$ of $\mathcal{C}$, consists of objects pairs $(X, x)$ with $X\in\mathcal{C}, x\in\mathrm{End}_{\mathcal{C}}(X)$ such that $x^n=0$ for some…

Category Theory · Mathematics 2021-11-30 Zhiwei Bai , Xiang Cao , Songtao Mao , Han Zhang , Yuehui Zhang

Consider an exact couple in a semiabelian category in the sense of Palamodov, i.e., in an additive category in which every morphism has a kernel as well as a cokernel and the induced morphism between coimage and image is always monic and…

Category Theory · Mathematics 2014-06-27 Yaroslav Kopylov , Sven-Ake Wegner

To characterize categorical constraints - associativity, commutativity and monoidality - in the context of quasimonoidal categories, from a cohomological point of view, we define the notion of a parity (quasi)complex. Applied to groups…

Category Theory · Mathematics 2007-05-23 Lucian M. Ionescu

We extend the framework of combinatorial model categories, so that the category of small presheaves over large indexing categories and ind-categories would be embraced by the new machinery called class-combinatorial model categories. The…

Algebraic Topology · Mathematics 2019-12-06 Boris Chorny , Jiří Rosický

Presentations of categories are a well-known algebraic tool to provide descriptions of categories by means of generators, for objects and morphisms, and relations on morphisms. We generalize here this notion, in order to consider situations…

Logic in Computer Science · Computer Science 2019-03-14 Pierre-Louis Curien , Samuel Mimram

This paper gives a uniform-theoretic refinement of classical homotopy theory. Both cubical sets (with connections) and uniform spaces admit classes of weak equivalences, special cases of classical weak equivalences, appropriate for the…

Algebraic Topology · Mathematics 2021-09-20 Sanjeevi Krishnan , Crichton Ogle

We construct and study projective and Reedy model category structures for bimodules and infinitesimal bimodules over topological operads. Both model structures produce the same homotopy categories. For the model categories in question, we…

Algebraic Topology · Mathematics 2021-06-10 Julien Ducoulombier , Benoit Fresse , Victor Turchin

Some basic features of the simultaneous inclusion of discrete fibrations and discrete opfibrations on a category A in the category of categories over A are studied; in particular, the reflections and the coreflections of the latter in the…

Category Theory · Mathematics 2007-05-23 Claudio Pisani

In the first part, we further advance the study of category theory in a strong balanced factorization category C [Pisani, 2008], a finitely complete category endowed with two reciprocally stable factorization systems such that X \to 1 is in…

Category Theory · Mathematics 2009-04-27 Claudio Pisani

We develop the basic theory of covers and envelopes in proto-exact categories. As an application, we prove the existence of enough injectives for categories of Banach modules over arbitrary Banach rings.

Category Theory · Mathematics 2026-03-10 Jack Kelly

We give a new construction, based on categorical logic, of Nori's $\mathbb Q$-linear abelian category of mixed motives associated to a cohomology or homology functor with values in finite-dimensional vector spaces over $\mathbb Q$. This new…

Algebraic Geometry · Mathematics 2016-05-17 Luca Barbieri-Viale , Olivia Caramello , Laurent Lafforgue

We consider an arbitrary Abelian category $\mathcal{A}$ and a subcategory $\mathcal{T}$ closed under extensions and direct summands, and characterize those $\mathcal{T}$ that are (semi-)special preenveloping in $\mathcal{A}$; as a…

Representation Theory · Mathematics 2021-12-28 Carlos E. Parra , Manuel Saorín , Simone Virili

We consider abelian length categories, a generalization of module categories over Artin algebras. Let $\mathcal{A}$ be an abelian length category of colocal type. We show that the lattice $\mathsf{S}(\mathcal{A})$ of full additive subobject…

Representation Theory · Mathematics 2018-06-26 Apolonia Gottwald

Using the Morita-type embedding, we show that any exact category with enough projectives has a realization as a (pre)resolving subcategory of a module category. When the exact category has enough injectives, the image of the embedding can…

Representation Theory · Mathematics 2019-07-30 Haruhisa Enomoto

We prove existence of equalizers in certain categories of cocomplete cocategories. This allows us to complete the proof of the fact that A-infinity functor categories arise as internal Hom-objects in the category of differential graded…

Category Theory · Mathematics 2007-06-13 Bernhard Keller , Oleksandr Manzyuk

Our work over the past years shows that not only the collection of (for instance) all topological spaces gives rise to a category, but also each topological space can be seen individually as a category by interpreting the convergence…

Category Theory · Mathematics 2008-04-03 Dirk Hofmann

We consider subtorus actions on complex toric varieties. A natural candidate for a categorical quotient of such an action is the so-called toric quotient, a universal object constructed in the toric category. We prove that if the toric…

Algebraic Geometry · Mathematics 2007-05-23 Annette A'Campo-Neuen

We study the properties of the relative derived category $D_{\mathscr{C}}^{b}$($\mathscr{A}$) of an abelian category $\mathscr{A}$ relative to a full and additive subcategory $\mathscr{C}$. In particular, when $\mathscr{A}=A{\text -}\mod$…

Representation Theory · Mathematics 2015-02-10 Huanhuan Li , Zhaoyong Huang

For a collection of subcategories satisfying a fixed set of conditions, for example thick subcategories of a triangulated category, we define a topological space called classifying space of subcategories. We show that this space classifies…

Category Theory · Mathematics 2017-09-12 Yong Liu