J 2023

Smallness in topology

ADÁMEK, Jiří, Miroslav HUŠEK, Jiří ROSICKÝ and Walter THOLEN

Basic information

Original name

Smallness in topology

Authors

ADÁMEK, Jiří (203 Czech Republic), Miroslav HUŠEK, Jiří ROSICKÝ (203 Czech Republic, guarantor, belonging to the institution) and Walter THOLEN

Edition

Quaestiones Mathematicae, TAYLOR & FRANCIS LTD, 2023, 1607-3606

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10101 Pure mathematics

Country of publisher

United Kingdom of Great Britain and Northern Ireland

Confidentiality degree

není předmětem státního či obchodního tajemství

References:

URL

Impact factor

Impact factor: 0.700 in 2022

RIV identification code

RIV/00216224:14310/23:00134276

Organization unit

Faculty of Science

DOI

http://dx.doi.org/10.2989/16073606.2023.2247720

UT WoS

001170576200001

Keywords in English

Finitely presentable object; finitely generated object; finitely small object; directed colimit; Hausdorff space; T0-space; T1-space; compact space

Tags

rivok

Tags

International impact, Reviewed
Změněno: 25/3/2024 09:26, Mgr. Marie Šípková, DiS.

Abstract

V originále

Quillen’s notion of small object and the Gabriel-Ulmer notion of finitely presentable or generated object are fundamental in homotopy theory and categorical algebra. Do these notions always lead to rather uninteresting classes of objects in categories of topological spaces, such as all finite discrete spaces, or just the empty space, as the examples and remarks in the existing literature may suggest? This article demonstrates that the establishment of full characterizations of these notions (and some natural variations thereof) in many familiar categories of spaces can be quite challenging and may lead to unexpected surprises. In fact, we show that there are significant differences in this regard even amongst the categories defined by the standard separation axioms, with the T1-separation condition standing out. The findings about these specific categories lead us to insights also when considering rather arbitrary full reflective subcategories of the category of all topological spaces.

Links

GA22-02964S, research and development project
Name: Obohacené kategorie a jejich aplikace (Acronym: ECATA)
Investor: Czech Science Foundation
Displayed: 5/11/2024 08:41