activity
20062025
most citedA cottage industry of lax extensions

12 citations · 60 across the 29 of their papers we have counts for

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28 papers · 1 filter

math.CT2025

Notions of Cauchy completeness for normed categories

Dirk Hofmann, Walter Tholen

As already mentioned by Lawvere in his 1973 paper, the characterisation of Cauchy completeness of metric spaces in terms of representability of adjoint distributors amounts to the…

math.CT2025

Topological lax comma categories

Maria Manuel Clementino, Dirk Hofmann, Rui Prezado

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

math.CT2024

Barr-coexactness for metric compact Hausdorff spaces

Marco Abbadini, Dirk Hofmann

Compact metric spaces form an important class of metric spaces, but the category that they define lacks many important properties such as completeness and cocompleteness. In recent…

math.CT2024

A variety of co-quasivarieties

Maria Manuel Clementino, Carlos Fitas, Dirk Hofmann

It is shown that the duals of several categories of topological flavour, like the categories of ordered sets, generalised metric spaces, probabilistic metric spaces, topological sp…

math.CT2024

Cauchy convergence in V-normed categories

Maria Manuel Clementino, Dirk Hofmann, Walter Tholen

Building on the notion of normed category as suggested by Lawvere, we introduce notions of Cauchy convergence and cocompleteness which differ from proposals in previous works. Key…

math.CT2022

Kantorovich Functors and Characteristic Logics for Behavioural Distances

Sergey Goncharov, Dirk Hofmann, Pedro Nora +2

Behavioural distances measure the deviation between states in quantitative systems, such as probabilistic or weighted systems. There is growing interest in generic approaches to be…

math.CT2021★ 2 cited

A Point-free Perspective on Lax extensions and Predicate liftings

Sergey Goncharov, Dirk Hofmann, Pedro Nora +2

Lax extensions of set functors play a key role in various areas including topology, concurrent systems, and modal logic, while predicate liftings provide a generic semantics of mod…

math.CT2020

Duality theory for enriched Priestley spaces

Dirk Hofmann, Pedro Nora

The term Stone-type duality often refers to a dual equivalence between a category of lattices or other partially ordered structures on one side and a category of topological struct…

math.CT2019

Hausdorff coalgebras

Dirk Hofmann, Pedro Nora

As composites of constant, (co)product, identity, and powerset functors, Kripke polynomial functors form a relevant class of -functors in the theory of coalgebras. Th…

math.CT2018

Cartesian closed exact completions in topology

Maria Manuel Clementino, Dirk Hofmann, Willian Ribeiro

Using generalized enriched categories, in this paper we show that Rosický's proof of cartesian closedness of the exact completion of the category of topological spaces can be exten…

math.CT2017

Convergence and quantale-enriched categories

Dirk Hofmann, Carla Reis

Generalising Nachbin's theory of "topology and order", in this paper we continue the study of quantale-enriched categories equipped with a compact Hausdorff topology. We compare th…

math.CT2017★ 2 cited

Aspects of algebraic Algebras

Dirk Hofmann, Lurdes Sousa

In this paper we investigate important categories lying strictly between the Kleisli category and the Eilenberg-Moore category, for a Kock-Zöberlein monad on an order-enriched cate…

math.CT2016★ 6 cited

Topology from enrichment: the curious case of partial metrics

Dirk Hofmann, Isar Stubbe

For any small quantaloid $\Q$, there is a new quantaloid $\D(\Q)$ of diagonals in $\Q$. If $\Q$ is divisible then so is $\D(\Q)$ (and vice versa), and then it is particularly inter…

math.CT2016

Enriched Stone-type dualities

Dirk Hofmann, Pedro Nora

A common feature of many duality results is that the involved equivalence functors are liftings of hom-functors into the two-element space resp. lattice. Due to this fact, we can o…

math.CT2015★ 12 cited

A cottage industry of lax extensions

Dirk Hofmann, Gavin J. Seal

In this work, we describe an adjunction between the comma category of SET-based monads under the V-powerset monad and the category of associative lax extensions of SET-based monads…

math.CT2014★ 1 cited

Representable (T, V)-categories

Dimitri Chikhladze, Maria Manuel Clementino, Dirk Hofmann

Working in the framework of -categories, for a symmetric monoidal closed category and a (not necessarily cartesian) monad , we present a common account to the study…

math.CT2014★ 1 cited

Some notes on Esakia spaces

Dirk Hofmann, Pedro Nora

Under Stone/Priestley duality for distributive lattices, Esakia spaces correspond to Heyting algebras which leads to the well-known dual equivalence between the category of Esakia…

math.CT2012

The enriched Vietoris monad on representable spaces

Dirk Hofmann

Employing a formal analogy between ordered sets and topological spaces, over the past years we have investigated a notion of cocompleteness for topological, approach and other kind…

math.CT2012

Exponential Kleisli monoids as Eilenberg-Moore algebras

Dirk Hofmann, Frédéric Mynard, Gavin J. Seal

Lax monoidal powerset-enriched monads yield a monoidal structure on the category of monoids in the Kleisli category of a monad. Exponentiable objects in this category are identifie…

math.CT2010★ 1 cited

A Duality of Quantale-Enriched Categories

Dirk Hofmann, Pawel Waszkiewicz

We describe a duality for quantale-enriched categories that extends the Lawson duality for continuous dcpos: for any saturated class J of modules that commute with certain weighted…

math.CT2010

Duality for distributive space

Dirk Hofmann

The main source of inspiration for the present paper is the work of R. Rosebrugh and R.J. Wood on constructive complete distributive lattices where the authors employ elegantly the…

math.CT2010

Approximation in quantale-enriched categories

Dirk Hofmann, Pawel Waszkiewicz

Our work is a fundamental study of the notion of approximation in V-categories and in (U,V)-categories, for a quantale V and the ultrafilter monad U. We introduce auxiliary, approx…

math.CT2010

Stone duality for topological theories

Dirk Hofmann, Isar Stubbe

In the context of categorical topology, more precisely that of T-categories [Hofmann, 2007], we define the notion of T-colimit as a particular colimit in a V-category. A complete a…

math.CT2008★ 8 cited

Relative injectivity as cocompleteness for a class of distributors

Maria Manuel Clementino, Dirk Hofmann

Notions and techniques of enriched category theory can be used to study topological structures, like metric spaces, topological spaces and approach spaces, in the context of topolo…