{"title":"Functions of self-adjoint operators under relatively bounded and relatively trace class perturbations","authors":"A. B. Aleksandrov, V. V. Peller","doi":"10.1002/mana.70000","DOIUrl":null,"url":null,"abstract":"<p>We study the behaviour of functions of self-adjoint operators under relatively bounded and relatively trace class perturbation. We introduce and study the class of relatively operator Lipschitz functions. An essential role is played by double operator integrals. We also consider the class of resolvent Lipschitz functions. Then we obtain a trace formula in the case of relatively trace class perturbations and show that the maximal class of function for which the trace formula holds in the case of relatively trace class perturbations coincides with the class of relatively operator Lipschitz functions. Our methods also give us a new approach to the inequality <span></span><math>\n <semantics>\n <mrow>\n <mrow>\n <mo>∫</mo>\n <mo>|</mo>\n <mrow>\n <mi>ξ</mi>\n </mrow>\n <mrow>\n <mo>(</mo>\n <mi>t</mi>\n <mo>)</mo>\n </mrow>\n <mo>|</mo>\n <mo>(</mo>\n <mn>1</mn>\n </mrow>\n <mo>+</mo>\n <msup>\n <mrow>\n <mo>|</mo>\n <mi>t</mi>\n <mo>|</mo>\n <mo>)</mo>\n </mrow>\n <mrow>\n <mo>−</mo>\n <mn>1</mn>\n </mrow>\n </msup>\n <mspace></mspace>\n <mi>d</mi>\n <mi>t</mi>\n <mo><</mo>\n <mi>∞</mi>\n </mrow>\n <annotation>$\\int |\\bm{\\xi }(t)|(1+|t|)^{-1}\\,{\\rm d}t<\\infty$</annotation>\n </semantics></math> for the spectral shift function <span></span><math>\n <semantics>\n <mrow>\n <mi>ξ</mi>\n </mrow>\n <annotation>$\\bm{\\xi }$</annotation>\n </semantics></math> in the case of relatively trace class perturbations.</p>","PeriodicalId":49853,"journal":{"name":"Mathematische Nachrichten","volume":"298 9","pages":"3027-3048"},"PeriodicalIF":0.8000,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Mathematische Nachrichten","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/mana.70000","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
We study the behaviour of functions of self-adjoint operators under relatively bounded and relatively trace class perturbation. We introduce and study the class of relatively operator Lipschitz functions. An essential role is played by double operator integrals. We also consider the class of resolvent Lipschitz functions. Then we obtain a trace formula in the case of relatively trace class perturbations and show that the maximal class of function for which the trace formula holds in the case of relatively trace class perturbations coincides with the class of relatively operator Lipschitz functions. Our methods also give us a new approach to the inequality for the spectral shift function in the case of relatively trace class perturbations.
期刊介绍:
Mathematische Nachrichten - Mathematical News publishes original papers on new results and methods that hold prospect for substantial progress in mathematics and its applications. All branches of analysis, algebra, number theory, geometry and topology, flow mechanics and theoretical aspects of stochastics are given special emphasis. Mathematische Nachrichten is indexed/abstracted in Current Contents/Physical, Chemical and Earth Sciences; Mathematical Review; Zentralblatt für Mathematik; Math Database on STN International, INSPEC; Science Citation Index