{"title":"l1 球的非中心部分","authors":"Hermann König","doi":"10.1016/j.aam.2024.102737","DOIUrl":null,"url":null,"abstract":"<div><p>We determine the maximal non-central hyperplane sections of the <span><math><msubsup><mrow><mi>l</mi></mrow><mrow><mn>1</mn></mrow><mrow><mi>n</mi></mrow></msubsup></math></span>-ball if the fixed distance of the hyperplane to the origin is between <span><math><mfrac><mrow><mn>1</mn></mrow><mrow><msqrt><mrow><mn>3</mn></mrow></msqrt></mrow></mfrac></math></span> and <span><math><mfrac><mrow><mn>1</mn></mrow><mrow><msqrt><mrow><mn>2</mn></mrow></msqrt></mrow></mfrac></math></span>. This adds to a result of Liu and Tkocz who considered the distance range between <span><math><mfrac><mrow><mn>1</mn></mrow><mrow><msqrt><mrow><mn>2</mn></mrow></msqrt></mrow></mfrac></math></span> and 1. For <span><math><mi>n</mi><mo>≥</mo><mn>4</mn></math></span>, the maximal sections are parallel to the <span><math><mo>(</mo><mi>n</mi><mo>−</mo><mn>1</mn><mo>)</mo></math></span>-dimensional coordinate planes. We also study non-central sections of the complex <span><math><msubsup><mrow><mi>l</mi></mrow><mrow><mo>∞</mo></mrow><mrow><mn>2</mn></mrow></msubsup></math></span>-ball, where the formulas are more complicated than in the real case. Also, the extrema are partially different compared to the real case.</p></div>","PeriodicalId":50877,"journal":{"name":"Advances in Applied Mathematics","volume":null,"pages":null},"PeriodicalIF":1.0000,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0196885824000691/pdfft?md5=4ac52765c27da32cc7db516354fb66e2&pid=1-s2.0-S0196885824000691-main.pdf","citationCount":"0","resultStr":"{\"title\":\"Non-central sections of the l1-ball\",\"authors\":\"Hermann König\",\"doi\":\"10.1016/j.aam.2024.102737\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>We determine the maximal non-central hyperplane sections of the <span><math><msubsup><mrow><mi>l</mi></mrow><mrow><mn>1</mn></mrow><mrow><mi>n</mi></mrow></msubsup></math></span>-ball if the fixed distance of the hyperplane to the origin is between <span><math><mfrac><mrow><mn>1</mn></mrow><mrow><msqrt><mrow><mn>3</mn></mrow></msqrt></mrow></mfrac></math></span> and <span><math><mfrac><mrow><mn>1</mn></mrow><mrow><msqrt><mrow><mn>2</mn></mrow></msqrt></mrow></mfrac></math></span>. This adds to a result of Liu and Tkocz who considered the distance range between <span><math><mfrac><mrow><mn>1</mn></mrow><mrow><msqrt><mrow><mn>2</mn></mrow></msqrt></mrow></mfrac></math></span> and 1. For <span><math><mi>n</mi><mo>≥</mo><mn>4</mn></math></span>, the maximal sections are parallel to the <span><math><mo>(</mo><mi>n</mi><mo>−</mo><mn>1</mn><mo>)</mo></math></span>-dimensional coordinate planes. We also study non-central sections of the complex <span><math><msubsup><mrow><mi>l</mi></mrow><mrow><mo>∞</mo></mrow><mrow><mn>2</mn></mrow></msubsup></math></span>-ball, where the formulas are more complicated than in the real case. Also, the extrema are partially different compared to the real case.</p></div>\",\"PeriodicalId\":50877,\"journal\":{\"name\":\"Advances in Applied Mathematics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.0000,\"publicationDate\":\"2024-07-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.sciencedirect.com/science/article/pii/S0196885824000691/pdfft?md5=4ac52765c27da32cc7db516354fb66e2&pid=1-s2.0-S0196885824000691-main.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Advances in Applied Mathematics\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0196885824000691\",\"RegionNum\":3,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATHEMATICS, APPLIED\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Advances in Applied Mathematics","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0196885824000691","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS, APPLIED","Score":null,"Total":0}
We determine the maximal non-central hyperplane sections of the -ball if the fixed distance of the hyperplane to the origin is between and . This adds to a result of Liu and Tkocz who considered the distance range between and 1. For , the maximal sections are parallel to the -dimensional coordinate planes. We also study non-central sections of the complex -ball, where the formulas are more complicated than in the real case. Also, the extrema are partially different compared to the real case.
期刊介绍:
Interdisciplinary in its coverage, Advances in Applied Mathematics is dedicated to the publication of original and survey articles on rigorous methods and results in applied mathematics. The journal features articles on discrete mathematics, discrete probability theory, theoretical statistics, mathematical biology and bioinformatics, applied commutative algebra and algebraic geometry, convexity theory, experimental mathematics, theoretical computer science, and other areas.
Emphasizing papers that represent a substantial mathematical advance in their field, the journal is an excellent source of current information for mathematicians, computer scientists, applied mathematicians, physicists, statisticians, and biologists. Over the past ten years, Advances in Applied Mathematics has published research papers written by many of the foremost mathematicians of our time.