{"title":"Length of Fully Faithful Framed Bicategories","authors":"Juan Orendain","doi":"10.1007/s10485-026-09861-3","DOIUrl":null,"url":null,"abstract":"<div><p>The length of a double category is a numerical invariant that quantifies the amount of ”work” required to rebuild the double category from its purely globular data. The minimal possible length is 1. It is conjectured that every framed bicategory realizes this minimal value. In this paper we confirm the conjecture for a subclass of framed bicategories: those whose unit squares are all cartesian/op-cartesian. We refer to such structures as fully-faithful/absolutely dense framed bicategories. The conjecture follows from a result relating the internal structure of fully faithful/absolutely dense framed bicategories to crossed products of decorated bicategories by <span>\\(\\pi _2\\)</span>-indexings.\n</p></div>","PeriodicalId":7952,"journal":{"name":"Applied Categorical Structures","volume":"34 4","pages":""},"PeriodicalIF":0.6000,"publicationDate":"2026-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Categorical Structures","FirstCategoryId":"100","ListUrlMain":"https://link.springer.com/article/10.1007/s10485-026-09861-3","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
The length of a double category is a numerical invariant that quantifies the amount of ”work” required to rebuild the double category from its purely globular data. The minimal possible length is 1. It is conjectured that every framed bicategory realizes this minimal value. In this paper we confirm the conjecture for a subclass of framed bicategories: those whose unit squares are all cartesian/op-cartesian. We refer to such structures as fully-faithful/absolutely dense framed bicategories. The conjecture follows from a result relating the internal structure of fully faithful/absolutely dense framed bicategories to crossed products of decorated bicategories by \(\pi _2\)-indexings.
期刊介绍:
Applied Categorical Structures focuses on applications of results, techniques and ideas from category theory to mathematics, physics and computer science. These include the study of topological and algebraic categories, representation theory, algebraic geometry, homological and homotopical algebra, derived and triangulated categories, categorification of (geometric) invariants, categorical investigations in mathematical physics, higher category theory and applications, categorical investigations in functional analysis, in continuous order theory and in theoretical computer science. In addition, the journal also follows the development of emerging fields in which the application of categorical methods proves to be relevant.
Applied Categorical Structures publishes both carefully refereed research papers and survey papers. It promotes communication and increases the dissemination of new results and ideas among mathematicians and computer scientists who use categorical methods in their research.