C. Bellavita, N. Chalmoukis, V. Daskalogiannis, G. Stylogiannis
{"title":"Generalized Hilbert operators arising from Hausdorff matrices","authors":"C. Bellavita, N. Chalmoukis, V. Daskalogiannis, G. Stylogiannis","doi":"10.1090/proc/16917","DOIUrl":null,"url":null,"abstract":"<p>For a finite, positive Borel measure <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"mu\"> <mml:semantics> <mml:mi>μ</mml:mi> <mml:annotation encoding=\"application/x-tex\">\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> on <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"left-parenthesis 0 comma 1 right-parenthesis\"> <mml:semantics> <mml:mrow> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mn>0</mml:mn> <mml:mo>,</mml:mo> <mml:mn>1</mml:mn> <mml:mo stretchy=\"false\">)</mml:mo> </mml:mrow> <mml:annotation encoding=\"application/x-tex\">(0,1)</mml:annotation> </mml:semantics> </mml:math> </inline-formula> we consider an infinite matrix <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"normal upper Gamma Subscript mu\"> <mml:semantics> <mml:msub> <mml:mi mathvariant=\"normal\">Γ</mml:mi> <mml:mi>μ</mml:mi> </mml:msub> <mml:annotation encoding=\"application/x-tex\">\\Gamma _\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, related to the classical Hausdorff matrix defined by the same measure <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"mu\"> <mml:semantics> <mml:mi>μ</mml:mi> <mml:annotation encoding=\"application/x-tex\">\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, in the same algebraic way that the Hilbert matrix is related to the Cesáro matrix. When <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"mu\"> <mml:semantics> <mml:mi>μ</mml:mi> <mml:annotation encoding=\"application/x-tex\">\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> is the Lebesgue measure, <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"normal upper Gamma Subscript mu\"> <mml:semantics> <mml:msub> <mml:mi mathvariant=\"normal\">Γ</mml:mi> <mml:mi>μ</mml:mi> </mml:msub> <mml:annotation encoding=\"application/x-tex\">\\Gamma _\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> reduces to the classical Hilbert matrix. We prove that the matrices <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"normal upper Gamma Subscript mu\"> <mml:semantics> <mml:msub> <mml:mi mathvariant=\"normal\">Γ</mml:mi> <mml:mi>μ</mml:mi> </mml:msub> <mml:annotation encoding=\"application/x-tex\">\\Gamma _\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> are not Hankel, unless <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"mu\"> <mml:semantics> <mml:mi>μ</mml:mi> <mml:annotation encoding=\"application/x-tex\">\\mu</mml:annotation> </mml:semantics> </mml:math> </inline-formula> is a constant multiple of the Lebesgue measure, we give necessary and sufficient conditions for their boundedness on the scale of Hardy spaces <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper H Superscript p Baseline comma 1 less-than-or-equal-to p greater-than normal infinity\"> <mml:semantics> <mml:mrow> <mml:msup> <mml:mi>H</mml:mi> <mml:mi>p</mml:mi> </mml:msup> <mml:mo>,</mml:mo> <mml:mspace width=\"thinmathspace\"/> <mml:mn>1</mml:mn> <mml:mo>≤</mml:mo> <mml:mi>p</mml:mi> <mml:mo>></mml:mo> <mml:mi mathvariant=\"normal\">∞</mml:mi> </mml:mrow> <mml:annotation encoding=\"application/x-tex\">H^p, \\, 1 \\leq p > \\infty</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, and we study their compactness and complete continuity properties. In the case <inline-formula content-type=\"math/mathml\"> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"2 less-than-or-equal-to p greater-than normal infinity\"> <mml:semantics> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>≤</mml:mo> <mml:mi>p</mml:mi> <mml:mo>></mml:mo> <mml:mi mathvariant=\"normal\">∞</mml:mi> </mml:mrow> <mml:annotation encoding=\"application/x-tex\">2\\leq p>\\infty</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, we are able to compute the exact value of the norm of the operator.</p>","PeriodicalId":20696,"journal":{"name":"Proceedings of the American Mathematical Society","volume":null,"pages":null},"PeriodicalIF":0.8000,"publicationDate":"2024-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Proceedings of the American Mathematical Society","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1090/proc/16917","RegionNum":3,"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
For a finite, positive Borel measure μ\mu on (0,1)(0,1) we consider an infinite matrix Γμ\Gamma _\mu, related to the classical Hausdorff matrix defined by the same measure μ\mu, in the same algebraic way that the Hilbert matrix is related to the Cesáro matrix. When μ\mu is the Lebesgue measure, Γμ\Gamma _\mu reduces to the classical Hilbert matrix. We prove that the matrices Γμ\Gamma _\mu are not Hankel, unless μ\mu is a constant multiple of the Lebesgue measure, we give necessary and sufficient conditions for their boundedness on the scale of Hardy spaces Hp,1≤p>∞H^p, \, 1 \leq p > \infty, and we study their compactness and complete continuity properties. In the case 2≤p>∞2\leq p>\infty, we are able to compute the exact value of the norm of the operator.
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