{"title":"Tight spans of fuzzy metric spaces","authors":"Yi Shi , Hui Yang","doi":"10.1016/j.fss.2025.109700","DOIUrl":null,"url":null,"abstract":"<div><div>Dress in 1984 introduced the concept of tight span of a metric space, allowing the space to be isometrically embedded into a larger metric space. This paper aims to extend this theory to fuzzy metric setting. More concretely, we define tight spans of fuzzy metric spaces as a key tool in the study of the appropriate extension. It is shown that any fuzzy metric space can be isometrically embedded into its tight span, with the embedding being an isomorphism when the fuzzy metric space is hyperconvex (or, equivalently, injective). Additionally, we explore tight extensions and essential extensions of fuzzy metric spaces, providing a precise formulation of their hyperconvex hulls and injective hulls.</div></div>","PeriodicalId":55130,"journal":{"name":"Fuzzy Sets and Systems","volume":"527 ","pages":"Article 109700"},"PeriodicalIF":3.1000,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Fuzzy Sets and Systems","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0165011425004385","RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2025/11/22 0:00:00","PubModel":"Epub","JCR":"Q2","JCRName":"COMPUTER SCIENCE, THEORY & METHODS","Score":null,"Total":0}
引用次数: 0
Abstract
Dress in 1984 introduced the concept of tight span of a metric space, allowing the space to be isometrically embedded into a larger metric space. This paper aims to extend this theory to fuzzy metric setting. More concretely, we define tight spans of fuzzy metric spaces as a key tool in the study of the appropriate extension. It is shown that any fuzzy metric space can be isometrically embedded into its tight span, with the embedding being an isomorphism when the fuzzy metric space is hyperconvex (or, equivalently, injective). Additionally, we explore tight extensions and essential extensions of fuzzy metric spaces, providing a precise formulation of their hyperconvex hulls and injective hulls.
期刊介绍:
Since its launching in 1978, the journal Fuzzy Sets and Systems has been devoted to the international advancement of the theory and application of fuzzy sets and systems. The theory of fuzzy sets now encompasses a well organized corpus of basic notions including (and not restricted to) aggregation operations, a generalized theory of relations, specific measures of information content, a calculus of fuzzy numbers. Fuzzy sets are also the cornerstone of a non-additive uncertainty theory, namely possibility theory, and of a versatile tool for both linguistic and numerical modeling: fuzzy rule-based systems. Numerous works now combine fuzzy concepts with other scientific disciplines as well as modern technologies.
In mathematics fuzzy sets have triggered new research topics in connection with category theory, topology, algebra, analysis. Fuzzy sets are also part of a recent trend in the study of generalized measures and integrals, and are combined with statistical methods. Furthermore, fuzzy sets have strong logical underpinnings in the tradition of many-valued logics.