{"title":"Degenerations of \n \n k\n $k$\n -positive surface group representations","authors":"Jonas Beyrer, Beatrice Pozzetti","doi":"10.1112/topo.12352","DOIUrl":null,"url":null,"abstract":"<p>We introduce <span></span><math>\n <semantics>\n <mi>k</mi>\n <annotation>$k$</annotation>\n </semantics></math>-<i>positive representations</i>, a large class of <span></span><math>\n <semantics>\n <mrow>\n <mo>{</mo>\n <mn>1</mn>\n <mo>,</mo>\n <mtext>…</mtext>\n <mo>,</mo>\n <mi>k</mi>\n <mo>}</mo>\n </mrow>\n <annotation>$\\lbrace 1,\\ldots ,k\\rbrace$</annotation>\n </semantics></math>-Anosov surface group representations into <span></span><math>\n <semantics>\n <mrow>\n <mi>PGL</mi>\n <mo>(</mo>\n <mi>E</mi>\n <mo>)</mo>\n </mrow>\n <annotation>$\\mathsf {PGL}(E)$</annotation>\n </semantics></math> that share many features with Hitchin representations, and we study their degenerations: unless they are Hitchin, they can be deformed to non-discrete representations, but any limit is at least <span></span><math>\n <semantics>\n <mrow>\n <mo>(</mo>\n <mi>k</mi>\n <mo>−</mo>\n <mn>3</mn>\n <mo>)</mo>\n </mrow>\n <annotation>$(k-3)$</annotation>\n </semantics></math>-positive and irreducible limits are <span></span><math>\n <semantics>\n <mrow>\n <mo>(</mo>\n <mi>k</mi>\n <mo>−</mo>\n <mn>1</mn>\n <mo>)</mo>\n </mrow>\n <annotation>$(k-1)$</annotation>\n </semantics></math>-positive. A major ingredient, of independent interest, is a general limit theorem for positively ratioed representations.</p>","PeriodicalId":56114,"journal":{"name":"Journal of Topology","volume":"17 3","pages":""},"PeriodicalIF":0.8000,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Topology","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1112/topo.12352","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
We introduce -positive representations, a large class of -Anosov surface group representations into that share many features with Hitchin representations, and we study their degenerations: unless they are Hitchin, they can be deformed to non-discrete representations, but any limit is at least -positive and irreducible limits are -positive. A major ingredient, of independent interest, is a general limit theorem for positively ratioed representations.
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.