{"title":"属1桥数卫星节","authors":"Scott A. Taylor, Maggy Tomova","doi":"10.1112/jlms.70260","DOIUrl":null,"url":null,"abstract":"<p>Let <span></span><math>\n <semantics>\n <mi>T</mi>\n <annotation>$T$</annotation>\n </semantics></math> be a satellite knot, link, or spatial graph in a 3-manifold <span></span><math>\n <semantics>\n <mi>M</mi>\n <annotation>$M$</annotation>\n </semantics></math> that is either <span></span><math>\n <semantics>\n <msup>\n <mi>S</mi>\n <mn>3</mn>\n </msup>\n <annotation>$S^3$</annotation>\n </semantics></math> or a lens space. Let <span></span><math>\n <semantics>\n <msub>\n <mi>b</mi>\n <mn>0</mn>\n </msub>\n <annotation>$\\mathfrak {b}_0$</annotation>\n </semantics></math> and <span></span><math>\n <semantics>\n <msub>\n <mi>b</mi>\n <mn>1</mn>\n </msub>\n <annotation>$\\mathfrak {b}_1$</annotation>\n </semantics></math> denote genus 0 and genus 1 bridge number, respectively. Suppose that <span></span><math>\n <semantics>\n <mi>T</mi>\n <annotation>$T$</annotation>\n </semantics></math> has a companion knot <span></span><math>\n <semantics>\n <mi>K</mi>\n <annotation>$K$</annotation>\n </semantics></math> (necessarily not the unknot) and wrapping number <span></span><math>\n <semantics>\n <mi>ω</mi>\n <annotation>$\\omega$</annotation>\n </semantics></math> with respect to <span></span><math>\n <semantics>\n <mi>K</mi>\n <annotation>$K$</annotation>\n </semantics></math>. When <span></span><math>\n <semantics>\n <mi>K</mi>\n <annotation>$K$</annotation>\n </semantics></math> is not a torus knot, we show that <span></span><math>\n <semantics>\n <mrow>\n <msub>\n <mi>b</mi>\n <mn>1</mn>\n </msub>\n <mrow>\n <mo>(</mo>\n <mi>T</mi>\n <mo>)</mo>\n </mrow>\n <mo>⩾</mo>\n <mi>ω</mi>\n <msub>\n <mi>b</mi>\n <mn>1</mn>\n </msub>\n <mrow>\n <mo>(</mo>\n <mi>K</mi>\n <mo>)</mo>\n </mrow>\n </mrow>\n <annotation>$\\mathfrak {b}_1(T)\\geqslant \\omega \\mathfrak {b}_1(K)$</annotation>\n </semantics></math>. There are previously known counterexamples if <span></span><math>\n <semantics>\n <mi>K</mi>\n <annotation>$K$</annotation>\n </semantics></math> is a torus knot. Along the way, we generalize and give a new proof of Schubert's result that <span></span><math>\n <semantics>\n <mrow>\n <msub>\n <mi>b</mi>\n <mn>0</mn>\n </msub>\n <mrow>\n <mo>(</mo>\n <mi>T</mi>\n <mo>)</mo>\n </mrow>\n <mo>⩾</mo>\n <mi>ω</mi>\n <msub>\n <mi>b</mi>\n <mn>0</mn>\n </msub>\n <mrow>\n <mo>(</mo>\n <mi>K</mi>\n <mo>)</mo>\n </mrow>\n </mrow>\n <annotation>$\\mathfrak {b}_0(T) \\geqslant \\omega \\mathfrak {b}_0(K)$</annotation>\n </semantics></math>. We also prove versions of the theorem applicable to when <span></span><math>\n <semantics>\n <mi>T</mi>\n <annotation>$T$</annotation>\n </semantics></math> is a “lensed satellite” and when there is a torus separating components of <span></span><math>\n <semantics>\n <mi>T</mi>\n <annotation>$T$</annotation>\n </semantics></math>.</p>","PeriodicalId":49989,"journal":{"name":"Journal of the London Mathematical Society-Second Series","volume":"112 2","pages":""},"PeriodicalIF":1.2000,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The genus 1 bridge number of satellite knots\",\"authors\":\"Scott A. Taylor, Maggy Tomova\",\"doi\":\"10.1112/jlms.70260\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Let <span></span><math>\\n <semantics>\\n <mi>T</mi>\\n <annotation>$T$</annotation>\\n </semantics></math> be a satellite knot, link, or spatial graph in a 3-manifold <span></span><math>\\n <semantics>\\n <mi>M</mi>\\n <annotation>$M$</annotation>\\n </semantics></math> that is either <span></span><math>\\n <semantics>\\n <msup>\\n <mi>S</mi>\\n <mn>3</mn>\\n </msup>\\n <annotation>$S^3$</annotation>\\n </semantics></math> or a lens space. Let <span></span><math>\\n <semantics>\\n <msub>\\n <mi>b</mi>\\n <mn>0</mn>\\n </msub>\\n <annotation>$\\\\mathfrak {b}_0$</annotation>\\n </semantics></math> and <span></span><math>\\n <semantics>\\n <msub>\\n <mi>b</mi>\\n <mn>1</mn>\\n </msub>\\n <annotation>$\\\\mathfrak {b}_1$</annotation>\\n </semantics></math> denote genus 0 and genus 1 bridge number, respectively. Suppose that <span></span><math>\\n <semantics>\\n <mi>T</mi>\\n <annotation>$T$</annotation>\\n </semantics></math> has a companion knot <span></span><math>\\n <semantics>\\n <mi>K</mi>\\n <annotation>$K$</annotation>\\n </semantics></math> (necessarily not the unknot) and wrapping number <span></span><math>\\n <semantics>\\n <mi>ω</mi>\\n <annotation>$\\\\omega$</annotation>\\n </semantics></math> with respect to <span></span><math>\\n <semantics>\\n <mi>K</mi>\\n <annotation>$K$</annotation>\\n </semantics></math>. When <span></span><math>\\n <semantics>\\n <mi>K</mi>\\n <annotation>$K$</annotation>\\n </semantics></math> is not a torus knot, we show that <span></span><math>\\n <semantics>\\n <mrow>\\n <msub>\\n <mi>b</mi>\\n <mn>1</mn>\\n </msub>\\n <mrow>\\n <mo>(</mo>\\n <mi>T</mi>\\n <mo>)</mo>\\n </mrow>\\n <mo>⩾</mo>\\n <mi>ω</mi>\\n <msub>\\n <mi>b</mi>\\n <mn>1</mn>\\n </msub>\\n <mrow>\\n <mo>(</mo>\\n <mi>K</mi>\\n <mo>)</mo>\\n </mrow>\\n </mrow>\\n <annotation>$\\\\mathfrak {b}_1(T)\\\\geqslant \\\\omega \\\\mathfrak {b}_1(K)$</annotation>\\n </semantics></math>. There are previously known counterexamples if <span></span><math>\\n <semantics>\\n <mi>K</mi>\\n <annotation>$K$</annotation>\\n </semantics></math> is a torus knot. Along the way, we generalize and give a new proof of Schubert's result that <span></span><math>\\n <semantics>\\n <mrow>\\n <msub>\\n <mi>b</mi>\\n <mn>0</mn>\\n </msub>\\n <mrow>\\n <mo>(</mo>\\n <mi>T</mi>\\n <mo>)</mo>\\n </mrow>\\n <mo>⩾</mo>\\n <mi>ω</mi>\\n <msub>\\n <mi>b</mi>\\n <mn>0</mn>\\n </msub>\\n <mrow>\\n <mo>(</mo>\\n <mi>K</mi>\\n <mo>)</mo>\\n </mrow>\\n </mrow>\\n <annotation>$\\\\mathfrak {b}_0(T) \\\\geqslant \\\\omega \\\\mathfrak {b}_0(K)$</annotation>\\n </semantics></math>. We also prove versions of the theorem applicable to when <span></span><math>\\n <semantics>\\n <mi>T</mi>\\n <annotation>$T$</annotation>\\n </semantics></math> is a “lensed satellite” and when there is a torus separating components of <span></span><math>\\n <semantics>\\n <mi>T</mi>\\n <annotation>$T$</annotation>\\n </semantics></math>.</p>\",\"PeriodicalId\":49989,\"journal\":{\"name\":\"Journal of the London Mathematical Society-Second Series\",\"volume\":\"112 2\",\"pages\":\"\"},\"PeriodicalIF\":1.2000,\"publicationDate\":\"2025-08-11\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of the London Mathematical Society-Second Series\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://londmathsoc.onlinelibrary.wiley.com/doi/10.1112/jlms.70260\",\"RegionNum\":2,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the London Mathematical Society-Second Series","FirstCategoryId":"100","ListUrlMain":"https://londmathsoc.onlinelibrary.wiley.com/doi/10.1112/jlms.70260","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
Let be a satellite knot, link, or spatial graph in a 3-manifold that is either or a lens space. Let and denote genus 0 and genus 1 bridge number, respectively. Suppose that has a companion knot (necessarily not the unknot) and wrapping number with respect to . When is not a torus knot, we show that . There are previously known counterexamples if is a torus knot. Along the way, we generalize and give a new proof of Schubert's result that . We also prove versions of the theorem applicable to when is a “lensed satellite” and when there is a torus separating components of .
期刊介绍:
The Journal of the London Mathematical Society has been publishing leading research in a broad range of mathematical subject areas since 1926. The Journal welcomes papers on subjects of general interest that represent a significant advance in mathematical knowledge, as well as submissions that are deemed to stimulate new interest and research activity.