{"title":"The relative James construction and its application to homotopy groups","authors":"Zhongjian Zhu, Tian Jin","doi":"10.1016/j.topol.2024.109043","DOIUrl":null,"url":null,"abstract":"<div><p>In this paper, we develop the new method to compute the homotopy groups of the mapping cone <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>f</mi></mrow></msub><mo>=</mo><mi>Y</mi><msub><mrow><mo>∪</mo></mrow><mrow><mi>f</mi></mrow></msub><mi>C</mi><mi>X</mi></math></span> beyond the metastable range by analysing the homotopy of the <em>n</em>-th filtration of the relative James construction <span><math><mi>J</mi><mo>(</mo><mi>X</mi><mo>,</mo><mi>A</mi><mo>)</mo></math></span> for CW-pair <span><math><mi>A</mi><mover><mrow><mo>↪</mo></mrow><mrow><mi>i</mi></mrow></mover><mi>X</mi></math></span>, defined by B. Gray, which is homotopy equivalent to the homotopy fiber of the pinch map <span><math><mi>X</mi><msub><mrow><mo>∪</mo></mrow><mrow><mi>i</mi></mrow></msub><mi>C</mi><mi>A</mi><mo>→</mo><mi>Σ</mi><mi>A</mi></math></span>. As an application, we compute the 5 and 6-dim unstable homotopy groups of 3-dimensional mod <span><math><msup><mrow><mn>2</mn></mrow><mrow><mi>r</mi></mrow></msup></math></span> Moore spaces for all positive integers <em>r</em>.</p></div>","PeriodicalId":51201,"journal":{"name":"Topology and its Applications","volume":"356 ","pages":"Article 109043"},"PeriodicalIF":0.6000,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Topology and its Applications","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0166864124002281","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
In this paper, we develop the new method to compute the homotopy groups of the mapping cone beyond the metastable range by analysing the homotopy of the n-th filtration of the relative James construction for CW-pair , defined by B. Gray, which is homotopy equivalent to the homotopy fiber of the pinch map . As an application, we compute the 5 and 6-dim unstable homotopy groups of 3-dimensional mod Moore spaces for all positive integers r.
期刊介绍:
Topology and its Applications is primarily concerned with publishing original research papers of moderate length. However, a limited number of carefully selected survey or expository papers are also included. The mathematical focus of the journal is that suggested by the title: Research in Topology. It is felt that it is inadvisable to attempt a definitive description of topology as understood for this journal. Certainly the subject includes the algebraic, general, geometric, and set-theoretic facets of topology as well as areas of interactions between topology and other mathematical disciplines, e.g. topological algebra, topological dynamics, functional analysis, category theory. Since the roles of various aspects of topology continue to change, the non-specific delineation of topics serves to reflect the current state of research in topology.
At regular intervals, the journal publishes a section entitled Open Problems in Topology, edited by J. van Mill and G.M. Reed. This is a status report on the 1100 problems listed in the book of the same name published by North-Holland in 1990, edited by van Mill and Reed.