{"title":"舒伯特多项式的补集","authors":"Neil J.Y. Fan , Peter L. Guo , Nicolas Y. Liu","doi":"10.1016/j.aam.2024.102691","DOIUrl":null,"url":null,"abstract":"<div><p>Let <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><mi>x</mi><mo>)</mo></math></span> be the Schubert polynomial for a permutation <em>w</em> of <span><math><mo>{</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo>,</mo><mo>…</mo><mo>,</mo><mi>n</mi><mo>}</mo></math></span>. For any given composition <em>μ</em>, we say that <span><math><msup><mrow><mi>x</mi></mrow><mrow><mi>μ</mi></mrow></msup><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> is the complement of <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><mi>x</mi><mo>)</mo></math></span> with respect to <em>μ</em>. When each part of <em>μ</em> is equal to <span><math><mi>n</mi><mo>−</mo><mn>1</mn></math></span>, Huh, Matherne, Mészáros and St. Dizier proved that the normalization of <span><math><msup><mrow><mi>x</mi></mrow><mrow><mi>μ</mi></mrow></msup><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> is a Lorentzian polynomial. They further conjectured that the normalization of <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><mi>x</mi><mo>)</mo></math></span> is Lorentzian. It can be shown that if there exists a composition <em>μ</em> such that <span><math><msup><mrow><mi>x</mi></mrow><mrow><mi>μ</mi></mrow></msup><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> is a Schubert polynomial, then the normalization of <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><mi>x</mi><mo>)</mo></math></span> will be Lorentzian. This motivates us to investigate the problem of when <span><math><msup><mrow><mi>x</mi></mrow><mrow><mi>μ</mi></mrow></msup><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> is a Schubert polynomial. We show that if <span><math><msup><mrow><mi>x</mi></mrow><mrow><mi>μ</mi></mrow></msup><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> is a Schubert polynomial, then <em>μ</em> must be a partition. We also consider the case when <em>μ</em> is the staircase partition <span><math><msub><mrow><mi>δ</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>=</mo><mo>(</mo><mi>n</mi><mo>−</mo><mn>1</mn><mo>,</mo><mo>…</mo><mo>,</mo><mn>1</mn><mo>,</mo><mn>0</mn><mo>)</mo></math></span>, and obtain that <span><math><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>δ</mi></mrow><mrow><mi>n</mi></mrow></msub></mrow></msup><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> is a Schubert polynomial if and only if <em>w</em> avoids the patterns 132 and 312. A conjectured characterization of when <span><math><msup><mrow><mi>x</mi></mrow><mrow><mi>μ</mi></mrow></msup><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> is a Schubert polynomial is proposed.</p></div>","PeriodicalId":50877,"journal":{"name":"Advances in Applied Mathematics","volume":null,"pages":null},"PeriodicalIF":1.0000,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Complements of Schubert polynomials\",\"authors\":\"Neil J.Y. Fan , Peter L. Guo , Nicolas Y. Liu\",\"doi\":\"10.1016/j.aam.2024.102691\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Let <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><mi>x</mi><mo>)</mo></math></span> be the Schubert polynomial for a permutation <em>w</em> of <span><math><mo>{</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo>,</mo><mo>…</mo><mo>,</mo><mi>n</mi><mo>}</mo></math></span>. For any given composition <em>μ</em>, we say that <span><math><msup><mrow><mi>x</mi></mrow><mrow><mi>μ</mi></mrow></msup><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> is the complement of <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><mi>x</mi><mo>)</mo></math></span> with respect to <em>μ</em>. When each part of <em>μ</em> is equal to <span><math><mi>n</mi><mo>−</mo><mn>1</mn></math></span>, Huh, Matherne, Mészáros and St. Dizier proved that the normalization of <span><math><msup><mrow><mi>x</mi></mrow><mrow><mi>μ</mi></mrow></msup><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> is a Lorentzian polynomial. They further conjectured that the normalization of <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><mi>x</mi><mo>)</mo></math></span> is Lorentzian. It can be shown that if there exists a composition <em>μ</em> such that <span><math><msup><mrow><mi>x</mi></mrow><mrow><mi>μ</mi></mrow></msup><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> is a Schubert polynomial, then the normalization of <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><mi>x</mi><mo>)</mo></math></span> will be Lorentzian. This motivates us to investigate the problem of when <span><math><msup><mrow><mi>x</mi></mrow><mrow><mi>μ</mi></mrow></msup><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> is a Schubert polynomial. We show that if <span><math><msup><mrow><mi>x</mi></mrow><mrow><mi>μ</mi></mrow></msup><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> is a Schubert polynomial, then <em>μ</em> must be a partition. We also consider the case when <em>μ</em> is the staircase partition <span><math><msub><mrow><mi>δ</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>=</mo><mo>(</mo><mi>n</mi><mo>−</mo><mn>1</mn><mo>,</mo><mo>…</mo><mo>,</mo><mn>1</mn><mo>,</mo><mn>0</mn><mo>)</mo></math></span>, and obtain that <span><math><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>δ</mi></mrow><mrow><mi>n</mi></mrow></msub></mrow></msup><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> is a Schubert polynomial if and only if <em>w</em> avoids the patterns 132 and 312. A conjectured characterization of when <span><math><msup><mrow><mi>x</mi></mrow><mrow><mi>μ</mi></mrow></msup><msub><mrow><mi>S</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> is a Schubert polynomial is proposed.</p></div>\",\"PeriodicalId\":50877,\"journal\":{\"name\":\"Advances in Applied Mathematics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.0000,\"publicationDate\":\"2024-03-22\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Advances in Applied Mathematics\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0196885824000228\",\"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/S0196885824000228","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS, APPLIED","Score":null,"Total":0}
Let be the Schubert polynomial for a permutation w of . For any given composition μ, we say that is the complement of with respect to μ. When each part of μ is equal to , Huh, Matherne, Mészáros and St. Dizier proved that the normalization of is a Lorentzian polynomial. They further conjectured that the normalization of is Lorentzian. It can be shown that if there exists a composition μ such that is a Schubert polynomial, then the normalization of will be Lorentzian. This motivates us to investigate the problem of when is a Schubert polynomial. We show that if is a Schubert polynomial, then μ must be a partition. We also consider the case when μ is the staircase partition , and obtain that is a Schubert polynomial if and only if w avoids the patterns 132 and 312. A conjectured characterization of when is a Schubert polynomial is proposed.
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.
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