{"title":"Grushin平面上的调和映射","authors":"Tomasz Adamowicz , Marcin Walicki , Ben Warhurst","doi":"10.1016/j.jde.2025.113806","DOIUrl":null,"url":null,"abstract":"<div><div>We study the Grushin spaces given by Hölder regular vector fields with the Carnot–Carathéodory distance, equipped with the natural weighted <em>n</em>-Lebesgue measure. It turns out that such a measure is <em>n</em>-Ahlfors regular and <em>p</em>-Muckenhoupt for <span><math><mi>p</mi><mo>></mo><mn>1</mn></math></span>. We investigate the related 2-Dirichlet energy and the harmonic mappings, and focus our attention on harmonic functions and mappings from domains in a Grushin plane to Euclidean spaces <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>m</mi></mrow></msup></math></span>, for <span><math><mi>m</mi><mo>≥</mo><mn>1</mn></math></span>. Our results enclose the second order Sobolev regularity, the Bochner identity and its consequences for the regularity of harmonic mappings, the Liouville-type theorems and a counterpart of the Lewy theorem. Furthermore, the Korevaar–Schoen energy of mappings on Grushin planes is studied and proven to be equivalent to the 2-Dirichlet energy. The discussion is illustrated by several examples.</div><div>We generalize some geometric and regularity results by Ferrari–Valdinoci <span><span>[23]</span></span> and Franchi–Serapioni <span><span>[30]</span></span>.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"453 ","pages":"Article 113806"},"PeriodicalIF":2.3000,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Harmonic mappings on Grushin planes\",\"authors\":\"Tomasz Adamowicz , Marcin Walicki , Ben Warhurst\",\"doi\":\"10.1016/j.jde.2025.113806\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>We study the Grushin spaces given by Hölder regular vector fields with the Carnot–Carathéodory distance, equipped with the natural weighted <em>n</em>-Lebesgue measure. It turns out that such a measure is <em>n</em>-Ahlfors regular and <em>p</em>-Muckenhoupt for <span><math><mi>p</mi><mo>></mo><mn>1</mn></math></span>. We investigate the related 2-Dirichlet energy and the harmonic mappings, and focus our attention on harmonic functions and mappings from domains in a Grushin plane to Euclidean spaces <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>m</mi></mrow></msup></math></span>, for <span><math><mi>m</mi><mo>≥</mo><mn>1</mn></math></span>. Our results enclose the second order Sobolev regularity, the Bochner identity and its consequences for the regularity of harmonic mappings, the Liouville-type theorems and a counterpart of the Lewy theorem. Furthermore, the Korevaar–Schoen energy of mappings on Grushin planes is studied and proven to be equivalent to the 2-Dirichlet energy. The discussion is illustrated by several examples.</div><div>We generalize some geometric and regularity results by Ferrari–Valdinoci <span><span>[23]</span></span> and Franchi–Serapioni <span><span>[30]</span></span>.</div></div>\",\"PeriodicalId\":15623,\"journal\":{\"name\":\"Journal of Differential Equations\",\"volume\":\"453 \",\"pages\":\"Article 113806\"},\"PeriodicalIF\":2.3000,\"publicationDate\":\"2025-10-08\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Differential Equations\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0022039625008332\",\"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 Differential Equations","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022039625008332","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
We study the Grushin spaces given by Hölder regular vector fields with the Carnot–Carathéodory distance, equipped with the natural weighted n-Lebesgue measure. It turns out that such a measure is n-Ahlfors regular and p-Muckenhoupt for . We investigate the related 2-Dirichlet energy and the harmonic mappings, and focus our attention on harmonic functions and mappings from domains in a Grushin plane to Euclidean spaces , for . Our results enclose the second order Sobolev regularity, the Bochner identity and its consequences for the regularity of harmonic mappings, the Liouville-type theorems and a counterpart of the Lewy theorem. Furthermore, the Korevaar–Schoen energy of mappings on Grushin planes is studied and proven to be equivalent to the 2-Dirichlet energy. The discussion is illustrated by several examples.
We generalize some geometric and regularity results by Ferrari–Valdinoci [23] and Franchi–Serapioni [30].
期刊介绍:
The Journal of Differential Equations is concerned with the theory and the application of differential equations. The articles published are addressed not only to mathematicians but also to those engineers, physicists, and other scientists for whom differential equations are valuable research tools.
Research Areas Include:
• Mathematical control theory
• Ordinary differential equations
• Partial differential equations
• Stochastic differential equations
• Topological dynamics
• Related topics