{"title":"Obstructions to homotopy invariance of loop coproduct via parameterized fixed-point theory","authors":"Lea Kenigsberg, Noah Porcelli","doi":"10.1112/topo.70066","DOIUrl":null,"url":null,"abstract":"<p>Given <span></span><math>\n <semantics>\n <mrow>\n <mi>f</mi>\n <mo>:</mo>\n <mi>M</mi>\n <mo>→</mo>\n <mi>N</mi>\n </mrow>\n <annotation>$f:M \\rightarrow N$</annotation>\n </semantics></math> a homotopy equivalence of compact manifolds with boundary, we use a construction of Geoghegan and Nicas to define its Reidemeister trace <span></span><math>\n <semantics>\n <mrow>\n <mrow>\n <mo>[</mo>\n <mi>T</mi>\n <mo>]</mo>\n </mrow>\n <mo>∈</mo>\n <msubsup>\n <mi>π</mi>\n <mn>1</mn>\n <mrow>\n <mi>s</mi>\n <mi>t</mi>\n </mrow>\n </msubsup>\n <mrow>\n <mo>(</mo>\n <mi>L</mi>\n <mi>N</mi>\n <mo>,</mo>\n <mi>N</mi>\n <mo>)</mo>\n </mrow>\n </mrow>\n <annotation>$[T] \\in \\pi _1^{st}(\\mathcal {L}N, N)$</annotation>\n </semantics></math>. We realize the Goresky–Hingston coproduct as a map of spectra, and show that the failure of <span></span><math>\n <semantics>\n <mi>f</mi>\n <annotation>$f$</annotation>\n </semantics></math> to entwine the spectral coproducts can be characterized by Chas–Sullivan multiplication with <span></span><math>\n <semantics>\n <mrow>\n <mo>[</mo>\n <mi>T</mi>\n <mo>]</mo>\n </mrow>\n <annotation>$[T]$</annotation>\n </semantics></math>. In particular, when <span></span><math>\n <semantics>\n <mi>f</mi>\n <annotation>$f$</annotation>\n </semantics></math> is a simple homotopy equivalence, the spectral coproducts of <span></span><math>\n <semantics>\n <mi>M</mi>\n <annotation>$M$</annotation>\n </semantics></math> and <span></span><math>\n <semantics>\n <mi>N</mi>\n <annotation>$N$</annotation>\n </semantics></math> agree.</p>","PeriodicalId":56114,"journal":{"name":"Journal of Topology","volume":"19 1","pages":""},"PeriodicalIF":1.6000,"publicationDate":"2026-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://londmathsoc.onlinelibrary.wiley.com/doi/epdf/10.1112/topo.70066","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Topology","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1112/topo.70066","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
Given a homotopy equivalence of compact manifolds with boundary, we use a construction of Geoghegan and Nicas to define its Reidemeister trace . We realize the Goresky–Hingston coproduct as a map of spectra, and show that the failure of to entwine the spectral coproducts can be characterized by Chas–Sullivan multiplication with . In particular, when is a simple homotopy equivalence, the spectral coproducts of and agree.
期刊介绍:
The Journal of Topology publishes papers of high quality and significance in topology, geometry and adjacent areas of mathematics. Interesting, important and often unexpected links connect topology and geometry with many other parts of mathematics, and the editors welcome submissions on exciting new advances concerning such links, as well as those in the core subject areas of the journal.
The Journal of Topology was founded in 2008. It is published quarterly with articles published individually online prior to appearing in a printed issue.