{"title":"Involutions on the product of projective space and sphere","authors":"Dimpi , Hemant Kumar Singh","doi":"10.1016/j.topol.2025.109481","DOIUrl":null,"url":null,"abstract":"<div><div>This paper focuses on the actions of <span><math><mi>G</mi><mo>=</mo><msub><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> on a finite CW-complex <em>X</em>, whose mod 2 cohomology is isomorphic to that of a product of projective space and sphere, <span><math><mi>F</mi><msup><mrow><mi>P</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>×</mo><msup><mrow><mi>S</mi></mrow><mrow><mi>m</mi></mrow></msup></math></span>, where <span><math><mi>F</mi></math></span> is either <span><math><mi>R</mi></math></span> or <span><math><mi>C</mi></math></span>. For the case when <em>X</em> is totally nonhomologous to zero in <span><math><msub><mrow><mi>X</mi></mrow><mrow><mi>G</mi></mrow></msub></math></span>, we determine the possible connected fixed point sets and construct examples illustrating these possibilities. We also address the case when <em>X</em> is not totally nonhomologous to zero in <span><math><msub><mrow><mi>X</mi></mrow><mrow><mi>G</mi></mrow></msub></math></span> under certain assumptions.</div><div>Furthermore, we compute the cohomology ring structure of the orbit spaces of free involutions on <em>X</em>. As an application, we derive the Borsuk-Ulam type results.</div></div>","PeriodicalId":51201,"journal":{"name":"Topology and its Applications","volume":"373 ","pages":"Article 109481"},"PeriodicalIF":0.6000,"publicationDate":"2025-06-19","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/S0166864125002792","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
This paper focuses on the actions of on a finite CW-complex X, whose mod 2 cohomology is isomorphic to that of a product of projective space and sphere, , where is either or . For the case when X is totally nonhomologous to zero in , we determine the possible connected fixed point sets and construct examples illustrating these possibilities. We also address the case when X is not totally nonhomologous to zero in under certain assumptions.
Furthermore, we compute the cohomology ring structure of the orbit spaces of free involutions on X. As an application, we derive the Borsuk-Ulam type results.
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.