J.A. Cruz-Chapital , A.D. Rojas-Sánchez , Á. Tamariz-Mascarúa , H. Villegas-Rodríguez
{"title":"可分离子集上的均匀收敛拓扑学","authors":"J.A. Cruz-Chapital , A.D. Rojas-Sánchez , Á. Tamariz-Mascarúa , H. Villegas-Rodríguez","doi":"10.1016/j.topol.2024.109135","DOIUrl":null,"url":null,"abstract":"<div><div>For a topological space <em>X</em>, let <span><math><msub><mrow><mo>(</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>X</mi></mrow></msup><mo>)</mo></mrow><mrow><mi>s</mi></mrow></msub><mo>:</mo><mo>=</mo><mo>(</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>X</mi></mrow></msup><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>)</mo></math></span> be the cartesian product of <span><math><mo>|</mo><mi>X</mi><mo>|</mo></math></span> copies of the real line <span><math><mi>R</mi></math></span> with the topology of the uniform convergence on separable subsets of <em>X</em>. In this article we analyze the subspace <span><math><mi>C</mi><mo>(</mo><mi>X</mi><mo>)</mo></math></span> of <span><math><msub><mrow><mo>(</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>X</mi></mrow></msup><mo>)</mo></mrow><mrow><mi>s</mi></mrow></msub></math></span> of all real-valued continuous functions on <em>X</em>, denoted by <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>(</mo><mi>X</mi><mo>)</mo></math></span>. We determine when <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>(</mo><mi>X</mi><mo>)</mo></math></span> is dense and when is closed in <span><math><msub><mrow><mo>(</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>X</mi></mrow></msup><mo>)</mo></mrow><mrow><mi>s</mi></mrow></msub></math></span>, and we obtain some results about the Baire property in <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>(</mo><mi>X</mi><mo>)</mo></math></span>. Finally, we determine the cellularity of <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>(</mo><mo>[</mo><mn>0</mn><mo>,</mo><mi>α</mi><mo>]</mo><mo>)</mo></math></span> where <span><math><mo>[</mo><mn>0</mn><mo>,</mo><mi>α</mi><mo>]</mo></math></span> is the space of ordinal numbers belonging to <span><math><mi>α</mi><mo>+</mo><mn>1</mn></math></span> with its usual order topology.</div></div>","PeriodicalId":51201,"journal":{"name":"Topology and its Applications","volume":"359 ","pages":"Article 109135"},"PeriodicalIF":0.6000,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The uniform convergence topology on separable subsets\",\"authors\":\"J.A. Cruz-Chapital , A.D. Rojas-Sánchez , Á. Tamariz-Mascarúa , H. Villegas-Rodríguez\",\"doi\":\"10.1016/j.topol.2024.109135\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>For a topological space <em>X</em>, let <span><math><msub><mrow><mo>(</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>X</mi></mrow></msup><mo>)</mo></mrow><mrow><mi>s</mi></mrow></msub><mo>:</mo><mo>=</mo><mo>(</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>X</mi></mrow></msup><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>)</mo></math></span> be the cartesian product of <span><math><mo>|</mo><mi>X</mi><mo>|</mo></math></span> copies of the real line <span><math><mi>R</mi></math></span> with the topology of the uniform convergence on separable subsets of <em>X</em>. In this article we analyze the subspace <span><math><mi>C</mi><mo>(</mo><mi>X</mi><mo>)</mo></math></span> of <span><math><msub><mrow><mo>(</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>X</mi></mrow></msup><mo>)</mo></mrow><mrow><mi>s</mi></mrow></msub></math></span> of all real-valued continuous functions on <em>X</em>, denoted by <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>(</mo><mi>X</mi><mo>)</mo></math></span>. We determine when <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>(</mo><mi>X</mi><mo>)</mo></math></span> is dense and when is closed in <span><math><msub><mrow><mo>(</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>X</mi></mrow></msup><mo>)</mo></mrow><mrow><mi>s</mi></mrow></msub></math></span>, and we obtain some results about the Baire property in <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>(</mo><mi>X</mi><mo>)</mo></math></span>. Finally, we determine the cellularity of <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>(</mo><mo>[</mo><mn>0</mn><mo>,</mo><mi>α</mi><mo>]</mo><mo>)</mo></math></span> where <span><math><mo>[</mo><mn>0</mn><mo>,</mo><mi>α</mi><mo>]</mo></math></span> is the space of ordinal numbers belonging to <span><math><mi>α</mi><mo>+</mo><mn>1</mn></math></span> with its usual order topology.</div></div>\",\"PeriodicalId\":51201,\"journal\":{\"name\":\"Topology and its Applications\",\"volume\":\"359 \",\"pages\":\"Article 109135\"},\"PeriodicalIF\":0.6000,\"publicationDate\":\"2024-11-13\",\"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/S0166864124003201\",\"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/S0166864124003201","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","Score":null,"Total":0}
The uniform convergence topology on separable subsets
For a topological space X, let be the cartesian product of copies of the real line with the topology of the uniform convergence on separable subsets of X. In this article we analyze the subspace of of all real-valued continuous functions on X, denoted by . We determine when is dense and when is closed in , and we obtain some results about the Baire property in . Finally, we determine the cellularity of where is the space of ordinal numbers belonging to with its usual order topology.
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.