{"title":"不同度数的随机多项式之和","authors":"Isabelle Kraus, Marcus Michelen, Sean O’Rourke","doi":"10.1090/tran/9128","DOIUrl":null,"url":null,"abstract":"<p>Let <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"mu\"> <mml:semantics> <mml:mi>μ<!-- μ --></mml:mi> <mml:annotation encoding=\"application/x-tex\">\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"nu\"> <mml:semantics> <mml:mi>ν<!-- ν --></mml:mi> <mml:annotation encoding=\"application/x-tex\">\\nu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> be probability measures in the complex plane, and let <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"p\"> <mml:semantics> <mml:mi>p</mml:mi> <mml:annotation encoding=\"application/x-tex\">p</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"q\"> <mml:semantics> <mml:mi>q</mml:mi> <mml:annotation encoding=\"application/x-tex\">q</mml:annotation> </mml:semantics> </mml:math> </inline-formula> be independent random polynomials of degree <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"n\"> <mml:semantics> <mml:mi>n</mml:mi> <mml:annotation encoding=\"application/x-tex\">n</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, whose roots are chosen independently from <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"mu\"> <mml:semantics> <mml:mi>μ<!-- μ --></mml:mi> <mml:annotation encoding=\"application/x-tex\">\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"nu\"> <mml:semantics> <mml:mi>ν<!-- ν --></mml:mi> <mml:annotation encoding=\"application/x-tex\">\\nu</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, respectively. Under assumptions on the measures <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"mu\"> <mml:semantics> <mml:mi>μ<!-- μ --></mml:mi> <mml:annotation encoding=\"application/x-tex\">\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"nu\"> <mml:semantics> <mml:mi>ν<!-- ν --></mml:mi> <mml:annotation encoding=\"application/x-tex\">\\nu</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, the limiting distribution for the zeros of the sum <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"p plus q\"> <mml:semantics> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>+</mml:mo> <mml:mi>q</mml:mi> </mml:mrow> <mml:annotation encoding=\"application/x-tex\">p+q</mml:annotation> </mml:semantics> </mml:math> </inline-formula> was computed by Reddy and the third author [J. Math. Anal. Appl. 495 (2021), p. 124719] as <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"n right-arrow normal infinity\"> <mml:semantics> <mml:mrow> <mml:mi>n</mml:mi> <mml:mo stretchy=\"false\">→<!-- → --></mml:mo> <mml:mi mathvariant=\"normal\">∞<!-- ∞ --></mml:mi> </mml:mrow> <mml:annotation encoding=\"application/x-tex\">n \\to \\infty</mml:annotation> </mml:semantics> </mml:math> </inline-formula>. In this paper, we generalize and extend this result to the case where <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"p\"> <mml:semantics> <mml:mi>p</mml:mi> <mml:annotation encoding=\"application/x-tex\">p</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"q\"> <mml:semantics> <mml:mi>q</mml:mi> <mml:annotation encoding=\"application/x-tex\">q</mml:annotation> </mml:semantics> </mml:math> </inline-formula> have different degrees. In this case, the logarithmic potential of the limiting distribution is given by the pointwise maximum of the logarithmic potentials of <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"mu\"> <mml:semantics> <mml:mi>μ<!-- μ --></mml:mi> <mml:annotation encoding=\"application/x-tex\">\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"nu\"> <mml:semantics> <mml:mi>ν<!-- ν --></mml:mi> <mml:annotation encoding=\"application/x-tex\">\\nu</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, scaled by the limiting ratio of the degrees of <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"p\"> <mml:semantics> <mml:mi>p</mml:mi> <mml:annotation encoding=\"application/x-tex\">p</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"q\"> <mml:semantics> <mml:mi>q</mml:mi> <mml:annotation encoding=\"application/x-tex\">q</mml:annotation> </mml:semantics> </mml:math> </inline-formula>. Additionally, our approach provides a complete description of the limiting distribution for the zeros of <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"p plus q\"> <mml:semantics> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>+</mml:mo> <mml:mi>q</mml:mi> </mml:mrow> <mml:annotation encoding=\"application/x-tex\">p + q</mml:annotation> </mml:semantics> </mml:math> </inline-formula> for any pair of measures <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"mu\"> <mml:semantics> <mml:mi>μ<!-- μ --></mml:mi> <mml:annotation encoding=\"application/x-tex\">\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"nu\"> <mml:semantics> <mml:mi>ν<!-- ν --></mml:mi> <mml:annotation encoding=\"application/x-tex\">\\nu</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, with different limiting behavior shown in the case when at least one of the measures fails to have a logarithmic moment.</p>","PeriodicalId":23209,"journal":{"name":"Transactions of the American Mathematical Society","volume":"34 1","pages":""},"PeriodicalIF":1.2000,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Sums of random polynomials with differing degrees\",\"authors\":\"Isabelle Kraus, Marcus Michelen, Sean O’Rourke\",\"doi\":\"10.1090/tran/9128\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Let <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"mu\\\"> <mml:semantics> <mml:mi>μ<!-- μ --></mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">\\\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"nu\\\"> <mml:semantics> <mml:mi>ν<!-- ν --></mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">\\\\nu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> be probability measures in the complex plane, and let <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"p\\\"> <mml:semantics> <mml:mi>p</mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">p</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"q\\\"> <mml:semantics> <mml:mi>q</mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">q</mml:annotation> </mml:semantics> </mml:math> </inline-formula> be independent random polynomials of degree <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"n\\\"> <mml:semantics> <mml:mi>n</mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">n</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, whose roots are chosen independently from <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"mu\\\"> <mml:semantics> <mml:mi>μ<!-- μ --></mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">\\\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"nu\\\"> <mml:semantics> <mml:mi>ν<!-- ν --></mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">\\\\nu</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, respectively. Under assumptions on the measures <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"mu\\\"> <mml:semantics> <mml:mi>μ<!-- μ --></mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">\\\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"nu\\\"> <mml:semantics> <mml:mi>ν<!-- ν --></mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">\\\\nu</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, the limiting distribution for the zeros of the sum <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"p plus q\\\"> <mml:semantics> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>+</mml:mo> <mml:mi>q</mml:mi> </mml:mrow> <mml:annotation encoding=\\\"application/x-tex\\\">p+q</mml:annotation> </mml:semantics> </mml:math> </inline-formula> was computed by Reddy and the third author [J. Math. Anal. Appl. 495 (2021), p. 124719] as <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"n right-arrow normal infinity\\\"> <mml:semantics> <mml:mrow> <mml:mi>n</mml:mi> <mml:mo stretchy=\\\"false\\\">→<!-- → --></mml:mo> <mml:mi mathvariant=\\\"normal\\\">∞<!-- ∞ --></mml:mi> </mml:mrow> <mml:annotation encoding=\\\"application/x-tex\\\">n \\\\to \\\\infty</mml:annotation> </mml:semantics> </mml:math> </inline-formula>. In this paper, we generalize and extend this result to the case where <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"p\\\"> <mml:semantics> <mml:mi>p</mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">p</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"q\\\"> <mml:semantics> <mml:mi>q</mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">q</mml:annotation> </mml:semantics> </mml:math> </inline-formula> have different degrees. In this case, the logarithmic potential of the limiting distribution is given by the pointwise maximum of the logarithmic potentials of <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"mu\\\"> <mml:semantics> <mml:mi>μ<!-- μ --></mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">\\\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"nu\\\"> <mml:semantics> <mml:mi>ν<!-- ν --></mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">\\\\nu</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, scaled by the limiting ratio of the degrees of <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"p\\\"> <mml:semantics> <mml:mi>p</mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">p</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"q\\\"> <mml:semantics> <mml:mi>q</mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">q</mml:annotation> </mml:semantics> </mml:math> </inline-formula>. Additionally, our approach provides a complete description of the limiting distribution for the zeros of <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"p plus q\\\"> <mml:semantics> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>+</mml:mo> <mml:mi>q</mml:mi> </mml:mrow> <mml:annotation encoding=\\\"application/x-tex\\\">p + q</mml:annotation> </mml:semantics> </mml:math> </inline-formula> for any pair of measures <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"mu\\\"> <mml:semantics> <mml:mi>μ<!-- μ --></mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">\\\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type=\\\"math/mathml\\\"> <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" alttext=\\\"nu\\\"> <mml:semantics> <mml:mi>ν<!-- ν --></mml:mi> <mml:annotation encoding=\\\"application/x-tex\\\">\\\\nu</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, with different limiting behavior shown in the case when at least one of the measures fails to have a logarithmic moment.</p>\",\"PeriodicalId\":23209,\"journal\":{\"name\":\"Transactions of the American Mathematical Society\",\"volume\":\"34 1\",\"pages\":\"\"},\"PeriodicalIF\":1.2000,\"publicationDate\":\"2024-01-25\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Transactions of the American Mathematical Society\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.1090/tran/9128\",\"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":"Transactions of the American Mathematical Society","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1090/tran/9128","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
摘要
设 μ \mu 和 ν \nu 是复平面上的概率度量,设 p p 和 q q 是阶数为 n n 的独立随机多项式,它们的根分别从 μ \mu 和 ν \nu 中独立选择。在对μ \mu 和 ν \nu 的度量进行假设的情况下,和 p + q p+q 的零点的极限分布由 Reddy 和第三位作者计算得出 [J. Math. Anal. Appl.在本文中,我们将这一结果推广到 p p 和 q q 具有不同度数的情况。在这种情况下,极限分布的对数势是由μ \mu 和 ν \nu 的对数势的点最大值给出的,并按 p p 和 q q 的极限度数比缩放。此外,我们的方法还完整地描述了任何一对度量 μ \mu 和 ν \nu 的 p + q p + q 的零点的极限分布,并在至少有一个度量不具有对数矩的情况下显示出不同的极限行为。
Let μ\mu and ν\nu be probability measures in the complex plane, and let pp and qq be independent random polynomials of degree nn, whose roots are chosen independently from μ\mu and ν\nu, respectively. Under assumptions on the measures μ\mu and ν\nu, the limiting distribution for the zeros of the sum p+qp+q was computed by Reddy and the third author [J. Math. Anal. Appl. 495 (2021), p. 124719] as n→∞n \to \infty. In this paper, we generalize and extend this result to the case where pp and qq have different degrees. In this case, the logarithmic potential of the limiting distribution is given by the pointwise maximum of the logarithmic potentials of μ\mu and ν\nu, scaled by the limiting ratio of the degrees of pp and qq. Additionally, our approach provides a complete description of the limiting distribution for the zeros of p+qp + q for any pair of measures μ\mu and ν\nu, with different limiting behavior shown in the case when at least one of the measures fails to have a logarithmic moment.
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