{"title":"A nonvariational Neumann problem for the Helmholtz equation","authors":"Massimo Lanza de Cristoforis","doi":"10.1007/s10231-025-01614-8","DOIUrl":null,"url":null,"abstract":"<div><p>We consider a bounded open subset <span>\\(\\Omega \\)</span> of <span>\\({\\mathbb {R}}^n\\)</span> of class <span>\\(C^{1,\\alpha }\\)</span> for some <span>\\(\\alpha \\in ]0,1[\\)</span> and we solve the Neumann problem for the Helmholtz equation both in <span>\\(\\Omega \\)</span> and in the exterior of <span>\\(\\Omega \\)</span>. We look for solutions in the space of <span>\\(\\alpha \\)</span>-Hölder continuous functions that may not have a classical normal derivative at the boundary points of <span>\\(\\Omega \\)</span> and that may have an infinite Dirichlet integral around the boundary of <span>\\(\\Omega \\)</span>. Namely for solutions that do not belong to the classical variational setting.</p></div>","PeriodicalId":8265,"journal":{"name":"Annali di Matematica Pura ed Applicata","volume":"205 2","pages":"591 - 633"},"PeriodicalIF":0.9000,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10231-025-01614-8.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Annali di Matematica Pura ed Applicata","FirstCategoryId":"100","ListUrlMain":"https://link.springer.com/article/10.1007/s10231-025-01614-8","RegionNum":3,"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
Abstract
We consider a bounded open subset \(\Omega \) of \({\mathbb {R}}^n\) of class \(C^{1,\alpha }\) for some \(\alpha \in ]0,1[\) and we solve the Neumann problem for the Helmholtz equation both in \(\Omega \) and in the exterior of \(\Omega \). We look for solutions in the space of \(\alpha \)-Hölder continuous functions that may not have a classical normal derivative at the boundary points of \(\Omega \) and that may have an infinite Dirichlet integral around the boundary of \(\Omega \). Namely for solutions that do not belong to the classical variational setting.
期刊介绍:
This journal, the oldest scientific periodical in Italy, was originally edited by Barnaba Tortolini and Francesco Brioschi and has appeared since 1850. Nowadays it is managed by a nonprofit organization, the Fondazione Annali di Matematica Pura ed Applicata, c.o. Dipartimento di Matematica "U. Dini", viale Morgagni 67A, 50134 Firenze, Italy, e-mail annali@math.unifi.it).
A board of Italian university professors governs the Fondazione and appoints the editors of the journal, whose responsibility it is to supervise the refereeing process. The names of governors and editors appear on the front page of each issue. Their addresses appear in the title pages of each issue.