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Related papers: Effective descent morphisms of ordered families

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We characterize effective descent morphisms of what we call filtered preorders, and apply these results to slightly improve a known result, due to the first author and F. Lucatelli Nunes, on the effective descent morphisms in lax comma…

Category Theory · Mathematics 2023-12-25 Maria Manuel Clementino , George Janelidze

Let $\mathsf{Ord} $ be the category of (pre)ordered sets. Unlike $\mathsf{Ord}/X$, whose behaviour is well-known, not much can be found in the literature about the lax comma 2-category $\mathsf{Ord} //X$. In this paper we show that the…

Category Theory · Mathematics 2023-11-13 Maria Manuel Clementino , Fernando Lucatelli Nunes

This paper investigates the interplay between properties of a topological space $X$, in particular of its natural order, and properties of the lax comma category $\mathsf{Top} \Downarrow X$, where $\mathsf{Top}$ denotes the category of…

Category Theory · Mathematics 2025-12-09 Maria Manuel Clementino , Dirk Hofmann , Rui Prezado

Let $A$ be a regular category with pushouts of regular epimorphisms by regular epimorphism and $Reg(A)$ the category of regular epimorphisms in $A$. We prove that every regular epimorphism in $Reg(A)$ is an effective descent morphism if,…

Category Theory · Mathematics 2015-04-20 Tomas Everaert

We investigate the properties of lax comma categories over a base category $X$, focusing on topologicity, extensivity, cartesian closedness, and descent. We establish that the forgetful functor from $\mathsf{Cat}//X$ to $\mathsf{Cat}$ is…

Category Theory · Mathematics 2024-06-13 Maria Manuel Clementino , Fernando Lucatelli Nunes , Rui Prezado

We study effective descent $ \mathcal V $-functors for cartesian monoidal categories $ \mathcal V $ with finite limits. This study is carried out via the properties enjoyed by the $2$-functor $ \mathcal V \mapsto \mathsf{Fam}(\mathcal V) $,…

Category Theory · Mathematics 2024-01-15 Rui Prezado

It is proved that a norm-decreasing homomorphism of commutative Banach algebras is an effective descent morphism for Banach modules if and only if it is a weak retract.

Functional Analysis · Mathematics 2017-01-20 Bachuki Mesablishvili

This thesis is an exposition of the author's contribution on effective descent morphisms in various categories of generalized categorical structures. It consists of: Chapter 1, where an elementary description of descent theory and the…

Category Theory · Mathematics 2025-02-14 Rui Prezado

We study lax epimorphisms in 2-categories, with special attention to $\mathsf{Cat}$ and $\mathcal{V}$-$\mathsf{Cat}$. We show that any 2-category with convenient colimits has an orthogonal $LaxEpi$-factorization system, and we give a…

Category Theory · Mathematics 2023-11-13 Fernando Lucatelli Nunes , Lurdes Sousa

We give sufficient conditions for effective descent in categories of (generalized) internal multicategories. Two approaches to study effective descent morphisms are pursued. The first one relies on establishing the category of internal…

Category Theory · Mathematics 2023-11-13 Rui Prezado , Fernando Lucatelli Nunes

Effective descent morphisms, originally defined in Grothendieck descent theory, form a class of special morphisms within a category. Essentially, an effective descent morphism enables bundles over its codomain to be fully described as…

Category Theory · Mathematics 2024-11-05 Fernando Lucatelli Nunes , Rui Prezado

By a closure space we will mean a pair $(A,\mathcal{C})$, in which $A$ is a set and $\mathcal{C}$ a set of subsets of $A$ closed under arbitrary intersections. The purpose of this paper is to initiate a development of descent theory of…

Category Theory · Mathematics 2023-10-26 George Janelidze , Manuela Sobral

In this paper we give a characterization of all order isomorphisms on some classes of convex functions. We deal with the class $Cvx(K)$ consisting of lower-semi-continuous convex functions defined on a convex set $K$, and its subclass…

Functional Analysis · Mathematics 2015-10-14 S. Artstein-Avidan , D. I. Florentin , V. D. Milman

We give a valuative criterion for when a smooth algebraic stack with a separated good moduli space is the quotient of a separated Deligne-Mumford stack by a torus. For doing so, we introduce a new class of morphisms, the so-called effective…

Algebraic Geometry · Mathematics 2024-01-29 Andrea Di Lorenzo , Giovanni Inchiostro

We develop the deformation-obstruction calculus for morphisms of complexes with a fixed lift of the codomain, to derived categories of flat nilpotent deformations of abelian categories. As an application, we give an alternative proof that…

Algebraic Geometry · Mathematics 2025-11-14 Pieter Belmans , Wendy Lowen , Shinnosuke Okawa , Andrea T. Ricolfi

Partially ordered sets (posets) play a universal role as an abstract structure in many areas of mathematics. For finite posets, an explicit enumeration of distinct partial orders on a set of unlabelled elements is known only up to a…

Combinatorics · Mathematics 2025-04-15 Christoph Minz

The paper gives the sufficient condition formulated in the syntactical form for all codescent morphisms of a variety of universal algebras satisfying the amalgamation property to be effective. This result is further used in proving that all…

Category Theory · Mathematics 2009-08-14 Dali Zangurashvili

We study three classes of local homomorphisms and their behavior with respect to the ascent and descent of the \emph{complete intersection} property. Crucially, they fall in between the already studied classes of complete intersection and…

Commutative Algebra · Mathematics 2025-08-26 Samuel Alvite , Javier Majadas

In this short note we explain the proof that proper surjective and faithfully flat maps are morphisms of effective descent for overconvergent isocrystals. We then show how to deduce the folklore theorem that for an arbitrary variety over a…

Number Theory · Mathematics 2017-07-12 Christopher Lazda

We consider categories of posets with $\mathfrak{C}$-valued structure sheaves for any category $\mathfrak{C}$ and see how they possess poset-indexed lax colimits that are both easy to describe and "weakly equivalent" to their ordinary…

Algebraic Geometry · Mathematics 2023-01-10 J. Sánchez González
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