{"title":"Hardy空间上的Davis-Wielandt壳和复合算子的数值范围","authors":"Xiaolu Liu, Liu Liu","doi":"10.1007/s43034-025-00468-8","DOIUrl":null,"url":null,"abstract":"<div><p>In this paper, we investigate the Davis-Wielandt shell and the numerical range of composition operators on the Hardy space. Firstly, we give a characterization of the Davis-Wielandt shell for multiplication operators with matrix symbols. Subsequently, we characterize the Davis-Wielandt shell of composition operators induced by constant functions, inner functions fixing 0 and elliptic automorphisms of order 2. Furthermore, we analyze the symmetry of the Davis-Wielandt shell for composition operators induced by parabolic automorphisms or elliptic automorphisms. Additionally, we present a complete description of the numerical range for composition operators induced by elliptic automorphisms of order 3.</p></div>","PeriodicalId":48858,"journal":{"name":"Annals of Functional Analysis","volume":"17 1","pages":""},"PeriodicalIF":1.0000,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The Davis-Wielandt shell and the numerical range of composition operators on the Hardy space\",\"authors\":\"Xiaolu Liu, Liu Liu\",\"doi\":\"10.1007/s43034-025-00468-8\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>In this paper, we investigate the Davis-Wielandt shell and the numerical range of composition operators on the Hardy space. Firstly, we give a characterization of the Davis-Wielandt shell for multiplication operators with matrix symbols. Subsequently, we characterize the Davis-Wielandt shell of composition operators induced by constant functions, inner functions fixing 0 and elliptic automorphisms of order 2. Furthermore, we analyze the symmetry of the Davis-Wielandt shell for composition operators induced by parabolic automorphisms or elliptic automorphisms. Additionally, we present a complete description of the numerical range for composition operators induced by elliptic automorphisms of order 3.</p></div>\",\"PeriodicalId\":48858,\"journal\":{\"name\":\"Annals of Functional Analysis\",\"volume\":\"17 1\",\"pages\":\"\"},\"PeriodicalIF\":1.0000,\"publicationDate\":\"2025-10-20\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Annals of Functional Analysis\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s43034-025-00468-8\",\"RegionNum\":3,\"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":"Annals of Functional Analysis","FirstCategoryId":"100","ListUrlMain":"https://link.springer.com/article/10.1007/s43034-025-00468-8","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
The Davis-Wielandt shell and the numerical range of composition operators on the Hardy space
In this paper, we investigate the Davis-Wielandt shell and the numerical range of composition operators on the Hardy space. Firstly, we give a characterization of the Davis-Wielandt shell for multiplication operators with matrix symbols. Subsequently, we characterize the Davis-Wielandt shell of composition operators induced by constant functions, inner functions fixing 0 and elliptic automorphisms of order 2. Furthermore, we analyze the symmetry of the Davis-Wielandt shell for composition operators induced by parabolic automorphisms or elliptic automorphisms. Additionally, we present a complete description of the numerical range for composition operators induced by elliptic automorphisms of order 3.
期刊介绍:
Annals of Functional Analysis is published by Birkhäuser on behalf of the Tusi Mathematical Research Group.
Ann. Funct. Anal. is a peer-reviewed electronic journal publishing papers of high standards with deep results, new ideas, profound impact, and significant implications in all areas of functional analysis and all modern related topics (e.g., operator theory). Ann. Funct. Anal. normally publishes original research papers numbering 18 or fewer pages in the journal’s style. Longer papers may be submitted to the Banach Journal of Mathematical Analysis or Advances in Operator Theory.
Ann. Funct. Anal. presents the best paper award yearly. The award in the year n is given to the best paper published in the years n-1 and n-2. The referee committee consists of selected editors of the journal.