Real-valued Lipschitz functions and metric properties of functions

The purpose of this article is to explore the very general phenomenon that a function between metric spaces has a particular metric property if and only if whenever it is followed in a composition by an arbitrary realvalued Lipschitz function, the composition has this property. The key tools we use...

Descripción completa

Detalles Bibliográficos
Autores: Beer, Gerald, Garrido Carballo, María Isabel
Tipo de recurso: artículo
Fecha de publicación:2020
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/128819
Acceso en línea:https://hdl.handle.net/20.500.14352/128819
Access Level:acceso abierto
Palabra clave:Cauchy continuous function
Locally Lipschitz function
Lipschitz spaces
Lipschitz in the small function
Uniformly continuous function
Análisis funcional y teoría de operadores
1202 Análisis y Análisis Funcional
Descripción
Sumario:The purpose of this article is to explore the very general phenomenon that a function between metric spaces has a particular metric property if and only if whenever it is followed in a composition by an arbitrary realvalued Lipschitz function, the composition has this property. The key tools we use are the Efremovic lemma [21] and a theorem of Garrido and Jaramillo [22] that says that a function h between metric spaces is Lipschitz if and only if whenever it is followed by a Lipschitz real-valued function in a composition, the composition is Lipschitz. We also present a streamlined proof of the Garrido-Jaramillo result itself, but one that still relies on their natural continuous linear operator from the Lipschitz space for the target space to the Lipschitz space for the domain. Separately, we include a highly applicable uniform closure theorem that yields the most important uniform density theorems for Lipschitz-type functions as special cases.