{"title":"可能具有无限跳跃集的 SBV 函数的近似值","authors":"Sergio Conti , Matteo Focardi , Flaviana Iurlano","doi":"10.1016/j.jfa.2024.110686","DOIUrl":null,"url":null,"abstract":"<div><div>We prove an approximation result for functions <span><math><mi>u</mi><mo>∈</mo><mi>S</mi><mi>B</mi><mi>V</mi><mo>(</mo><mi>Ω</mi><mo>;</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>m</mi></mrow></msup><mo>)</mo></math></span> such that ∇<em>u</em> is <em>p</em>-integrable, <span><math><mn>1</mn><mo>≤</mo><mi>p</mi><mo><</mo><mo>∞</mo></math></span>, and <span><math><msub><mrow><mi>g</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>(</mo><mo>|</mo><mo>[</mo><mi>u</mi><mo>]</mo><mo>|</mo><mo>)</mo></math></span> is integrable over the jump set (whose <span><math><msup><mrow><mi>H</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msup></math></span> measure is possibly infinite), for some continuous, nondecreasing, subadditive function <span><math><msub><mrow><mi>g</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>, with <span><math><msubsup><mrow><mi>g</mi></mrow><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup><mo>(</mo><mn>0</mn><mo>)</mo><mo>=</mo><mo>{</mo><mn>0</mn><mo>}</mo></math></span>. The approximating functions <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub></math></span> are piecewise affine with piecewise affine jump set; the convergence is that of <span><math><msup><mrow><mi>L</mi></mrow><mrow><mn>1</mn></mrow></msup></math></span> for <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub></math></span> and the convergence in energy for <span><math><mo>|</mo><mi>∇</mi><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub><msup><mrow><mo>|</mo></mrow><mrow><mi>p</mi></mrow></msup></math></span> and <span><math><mi>g</mi><mo>(</mo><mo>[</mo><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub><mo>]</mo><mo>,</mo><msub><mrow><mi>ν</mi></mrow><mrow><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub></mrow></msub><mo>)</mo></math></span> for suitable functions <em>g</em>. In particular, <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub></math></span> converges to <em>u BV</em>-strictly, area-strictly, and strongly in <em>BV</em> after composition with a bilipschitz map. If in addition <span><math><msup><mrow><mi>H</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msup><mo>(</mo><msub><mrow><mi>J</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>)</mo><mo><</mo><mo>∞</mo></math></span>, we also have convergence of <span><math><msup><mrow><mi>H</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msup><mo>(</mo><msub><mrow><mi>J</mi></mrow><mrow><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub></mrow></msub><mo>)</mo></math></span> to <span><math><msup><mrow><mi>H</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msup><mo>(</mo><msub><mrow><mi>J</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>)</mo></math></span>.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":null,"pages":null},"PeriodicalIF":1.7000,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Approximation of SBV functions with possibly infinite jump set\",\"authors\":\"Sergio Conti , Matteo Focardi , Flaviana Iurlano\",\"doi\":\"10.1016/j.jfa.2024.110686\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>We prove an approximation result for functions <span><math><mi>u</mi><mo>∈</mo><mi>S</mi><mi>B</mi><mi>V</mi><mo>(</mo><mi>Ω</mi><mo>;</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>m</mi></mrow></msup><mo>)</mo></math></span> such that ∇<em>u</em> is <em>p</em>-integrable, <span><math><mn>1</mn><mo>≤</mo><mi>p</mi><mo><</mo><mo>∞</mo></math></span>, and <span><math><msub><mrow><mi>g</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>(</mo><mo>|</mo><mo>[</mo><mi>u</mi><mo>]</mo><mo>|</mo><mo>)</mo></math></span> is integrable over the jump set (whose <span><math><msup><mrow><mi>H</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msup></math></span> measure is possibly infinite), for some continuous, nondecreasing, subadditive function <span><math><msub><mrow><mi>g</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>, with <span><math><msubsup><mrow><mi>g</mi></mrow><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup><mo>(</mo><mn>0</mn><mo>)</mo><mo>=</mo><mo>{</mo><mn>0</mn><mo>}</mo></math></span>. The approximating functions <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub></math></span> are piecewise affine with piecewise affine jump set; the convergence is that of <span><math><msup><mrow><mi>L</mi></mrow><mrow><mn>1</mn></mrow></msup></math></span> for <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub></math></span> and the convergence in energy for <span><math><mo>|</mo><mi>∇</mi><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub><msup><mrow><mo>|</mo></mrow><mrow><mi>p</mi></mrow></msup></math></span> and <span><math><mi>g</mi><mo>(</mo><mo>[</mo><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub><mo>]</mo><mo>,</mo><msub><mrow><mi>ν</mi></mrow><mrow><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub></mrow></msub><mo>)</mo></math></span> for suitable functions <em>g</em>. In particular, <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub></math></span> converges to <em>u BV</em>-strictly, area-strictly, and strongly in <em>BV</em> after composition with a bilipschitz map. If in addition <span><math><msup><mrow><mi>H</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msup><mo>(</mo><msub><mrow><mi>J</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>)</mo><mo><</mo><mo>∞</mo></math></span>, we also have convergence of <span><math><msup><mrow><mi>H</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msup><mo>(</mo><msub><mrow><mi>J</mi></mrow><mrow><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub></mrow></msub><mo>)</mo></math></span> to <span><math><msup><mrow><mi>H</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msup><mo>(</mo><msub><mrow><mi>J</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>)</mo></math></span>.</div></div>\",\"PeriodicalId\":15750,\"journal\":{\"name\":\"Journal of Functional Analysis\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.7000,\"publicationDate\":\"2024-09-19\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Functional Analysis\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0022123624003744\",\"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":"Journal of Functional Analysis","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022123624003744","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
Approximation of SBV functions with possibly infinite jump set
We prove an approximation result for functions such that ∇u is p-integrable, , and is integrable over the jump set (whose measure is possibly infinite), for some continuous, nondecreasing, subadditive function , with . The approximating functions are piecewise affine with piecewise affine jump set; the convergence is that of for and the convergence in energy for and for suitable functions g. In particular, converges to u BV-strictly, area-strictly, and strongly in BV after composition with a bilipschitz map. If in addition , we also have convergence of to .
期刊介绍:
The Journal of Functional Analysis presents original research papers in all scientific disciplines in which modern functional analysis plays a basic role. Articles by scientists in a variety of interdisciplinary areas are published.
Research Areas Include:
• Significant applications of functional analysis, including those to other areas of mathematics
• New developments in functional analysis
• Contributions to important problems in and challenges to functional analysis