{"title":"Endpoint estimates of fractional integral operators when α > n","authors":"Liang Huang , Hanli Tang , Caifeng Zhang","doi":"10.1016/j.bulsci.2024.103569","DOIUrl":null,"url":null,"abstract":"<div><div>In this paper we prove the reverse endpoint estimate of fractional integral operators<span><span><span><math><mfrac><mrow><mi>n</mi></mrow><mrow><mi>α</mi></mrow></mfrac><msubsup><mrow><mi>v</mi></mrow><mrow><mi>n</mi></mrow><mrow><mn>1</mn><mo>−</mo><mfrac><mrow><mi>α</mi></mrow><mrow><mi>n</mi></mrow></mfrac></mrow></msubsup><msub><mrow><mo>‖</mo><mi>f</mi><mo>‖</mo></mrow><mrow><msup><mrow><mi>L</mi></mrow><mrow><mn>1</mn></mrow></msup></mrow></msub><mo>≤</mo><msub><mrow><mo>‖</mo><msub><mrow><mi>I</mi></mrow><mrow><mi>α</mi></mrow></msub><mi>f</mi><mo>‖</mo></mrow><mrow><msup><mrow><mi>L</mi></mrow><mrow><mfrac><mrow><mi>n</mi></mrow><mrow><mi>n</mi><mo>−</mo><mi>α</mi></mrow></mfrac><mo>,</mo><mo>∞</mo></mrow></msup></mrow></msub></math></span></span></span> when <span><math><mi>α</mi><mo>></mo><mi>n</mi></math></span> for nonnegative function <span><math><mi>f</mi><mo>∈</mo><msup><mrow><mi>L</mi></mrow><mrow><mn>1</mn></mrow></msup><mo>(</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>)</mo></math></span>. And we also show that<span><span><span><math><msub><mrow><mo>‖</mo><msub><mrow><mi>I</mi></mrow><mrow><mi>α</mi></mrow></msub><mi>f</mi><mo>‖</mo></mrow><mrow><msup><mrow><mi>L</mi></mrow><mrow><mfrac><mrow><mi>n</mi></mrow><mrow><mi>n</mi><mo>−</mo><mi>α</mi></mrow></mfrac><mo>,</mo><mo>∞</mo></mrow></msup></mrow></msub><mo>≤</mo><msubsup><mrow><mi>v</mi></mrow><mrow><mi>n</mi></mrow><mrow><mn>1</mn><mo>−</mo><mfrac><mrow><mi>α</mi></mrow><mrow><mi>n</mi></mrow></mfrac></mrow></msubsup><msub><mrow><mo>‖</mo><mi>f</mi><mo>‖</mo></mrow><mrow><msup><mrow><mi>L</mi></mrow><mrow><mn>1</mn></mrow></msup></mrow></msub><mo>,</mo></math></span></span></span> where <span><math><mi>α</mi><mo>></mo><mi>n</mi></math></span>, <span><math><mn>0</mn><mo>≤</mo><mi>f</mi><mo>∈</mo><msubsup><mrow><mi>L</mi></mrow><mrow><mi>n</mi><mo>−</mo><mi>α</mi></mrow><mrow><mn>1</mn></mrow></msubsup><mo>(</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>)</mo></math></span> and the constant <span><math><msubsup><mrow><mi>v</mi></mrow><mrow><mi>n</mi></mrow><mrow><mn>1</mn><mo>−</mo><mfrac><mrow><mi>α</mi></mrow><mrow><mi>n</mi></mrow></mfrac></mrow></msubsup></math></span> is sharp. Moreover we establish the limiting weak type behaviors for fractional integral operators when <span><math><mi>α</mi><mo>></mo><mi>n</mi></math></span>. Specifically, there holds<span><span><span><math><munder><mi>lim</mi><mrow><mi>λ</mi><mo>→</mo><mn>0</mn></mrow></munder><mo></mo><mi>λ</mi><mo>|</mo><mo>{</mo><mi>x</mi><mo>∈</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>:</mo><msub><mrow><mi>I</mi></mrow><mrow><mi>α</mi></mrow></msub><mo>(</mo><mi>f</mi><mo>)</mo><mo>(</mo><mi>x</mi><mo>)</mo><mo><</mo><mi>λ</mi><mo>}</mo><msup><mrow><mo>|</mo></mrow><mrow><mfrac><mrow><mi>n</mi><mo>−</mo><mi>α</mi></mrow><mrow><mi>n</mi></mrow></mfrac></mrow></msup><mo>=</mo><mo>∞</mo><mspace></mspace><mtext> for any </mtext><mn>0</mn><mo><</mo><mi>f</mi><mo>∈</mo><msup><mrow><mi>L</mi></mrow><mrow><mn>1</mn></mrow></msup><mo>(</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>)</mo><mo>,</mo><munder><mi>lim</mi><mrow><mi>λ</mi><mo>→</mo><mo>+</mo><mo>∞</mo></mrow></munder><mo></mo><mi>λ</mi><mo>|</mo><mo>{</mo><mi>x</mi><mo>∈</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>:</mo><msub><mrow><mi>I</mi></mrow><mrow><mi>α</mi></mrow></msub><mo>(</mo><mi>f</mi><mo>)</mo><mo>(</mo><mi>x</mi><mo>)</mo><mo><</mo><mi>λ</mi><mo>}</mo><msup><mrow><mo>|</mo></mrow><mrow><mfrac><mrow><mi>n</mi><mo>−</mo><mi>α</mi></mrow><mrow><mi>n</mi></mrow></mfrac></mrow></msup><mo>=</mo><msubsup><mrow><mi>v</mi></mrow><mrow><mi>n</mi></mrow><mrow><mfrac><mrow><mi>n</mi><mo>−</mo><mi>α</mi></mrow><mrow><mi>n</mi></mrow></mfrac></mrow></msubsup><msub><mrow><mo>‖</mo><mi>f</mi><mo>‖</mo></mrow><mrow><msup><mrow><mi>L</mi></mrow><mrow><mn>1</mn></mrow></msup></mrow></msub><mspace></mspace><mspace></mspace><mtext> for any </mtext><mn>0</mn><mo>≤</mo><mi>f</mi><mo>∈</mo><msubsup><mrow><mi>L</mi></mrow><mrow><mi>n</mi><mo>−</mo><mi>α</mi></mrow><mrow><mn>1</mn></mrow></msubsup><mo>(</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>)</mo><mo>.</mo></math></span></span></span></div></div>","PeriodicalId":55313,"journal":{"name":"Bulletin des Sciences Mathematiques","volume":"199 ","pages":"Article 103569"},"PeriodicalIF":1.3000,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Bulletin des Sciences Mathematiques","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0007449724001878","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS, APPLIED","Score":null,"Total":0}
引用次数: 0
Abstract
In this paper we prove the reverse endpoint estimate of fractional integral operators when for nonnegative function . And we also show that where , and the constant is sharp. Moreover we establish the limiting weak type behaviors for fractional integral operators when . Specifically, there holds