{"title":"不含 R3-集合、R4-连续面和 s-点的连续面伪变形的回缩和回缩","authors":"Félix Capulín, Mario Flores-González , David Maya","doi":"10.1016/j.topol.2024.108937","DOIUrl":null,"url":null,"abstract":"<div><p>A <em>continuum</em> is a nondegenerate, compact, connected, metric space. A topological property <em>P</em> is <em>invariant under retraction</em> provided that each retract of a continuum having <em>P</em> has <em>P</em>, and <em>P</em> is <em>reversible under retraction by pseudo-deformation</em> if the condition a subcontinuum of a continuum <em>X</em> has <em>P</em> implies that <em>X</em> has <em>P</em>. In this paper, we prove that the absence of <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>3</mn></mrow></msup></math></span>-sets, the absence of <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>4</mn></mrow></msup></math></span>-continua and the absence of s-points are reversible under retractions by pseudo-deformation, and the absence of <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>3</mn></mrow></msup></math></span>-sets and the absence of <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>4</mn></mrow></msup></math></span>-continua are invariant under retractions while the absence of s-points is not.</p></div>","PeriodicalId":51201,"journal":{"name":"Topology and its Applications","volume":null,"pages":null},"PeriodicalIF":0.6000,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Retracts and retracts by pseudo-deformation of continua without R3-sets, R4-continua, and s-points\",\"authors\":\"Félix Capulín, Mario Flores-González , David Maya\",\"doi\":\"10.1016/j.topol.2024.108937\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>A <em>continuum</em> is a nondegenerate, compact, connected, metric space. A topological property <em>P</em> is <em>invariant under retraction</em> provided that each retract of a continuum having <em>P</em> has <em>P</em>, and <em>P</em> is <em>reversible under retraction by pseudo-deformation</em> if the condition a subcontinuum of a continuum <em>X</em> has <em>P</em> implies that <em>X</em> has <em>P</em>. In this paper, we prove that the absence of <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>3</mn></mrow></msup></math></span>-sets, the absence of <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>4</mn></mrow></msup></math></span>-continua and the absence of s-points are reversible under retractions by pseudo-deformation, and the absence of <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>3</mn></mrow></msup></math></span>-sets and the absence of <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>4</mn></mrow></msup></math></span>-continua are invariant under retractions while the absence of s-points is not.</p></div>\",\"PeriodicalId\":51201,\"journal\":{\"name\":\"Topology and its Applications\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.6000,\"publicationDate\":\"2024-05-03\",\"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/S0166864124001226\",\"RegionNum\":4,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Topology and its Applications","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0166864124001226","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
摘要
连续体是一个非enerate、紧凑、连通的度量空间。如果连续统 X 的子连续统具有 P 的条件意味着 X 具有 P,则 P 在通过伪变形缩回时是可逆的。在本文中,我们证明了 R3 集的缺失、R4-continua 的缺失和 s 点的缺失在通过伪变形的缩回下是可逆的,并且 R3 集的缺失和 R4-continua 的缺失在缩回下是不变的,而 s 点的缺失则不是。
Retracts and retracts by pseudo-deformation of continua without R3-sets, R4-continua, and s-points
A continuum is a nondegenerate, compact, connected, metric space. A topological property P is invariant under retraction provided that each retract of a continuum having P has P, and P is reversible under retraction by pseudo-deformation if the condition a subcontinuum of a continuum X has P implies that X has P. In this paper, we prove that the absence of -sets, the absence of -continua and the absence of s-points are reversible under retractions by pseudo-deformation, and the absence of -sets and the absence of -continua are invariant under retractions while the absence of s-points is not.
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.