{"title":"Hardy空间上复合算子的角导数和紧致性","authors":"Dimitrios Betsakos","doi":"10.7900/JOT.2018APR18.2196","DOIUrl":null,"url":null,"abstract":"Let Do be a simply connected subdomain of the unit disk and A be a compact subset of Do. Let φ be a universal covering map for Do \\ A. We prove that the composition operator Cφ is compact on the Hardy space H if and only if φ does not have an angular derivative at any point of the unit circle. This result extends a theorem of M.M. Jones.","PeriodicalId":50104,"journal":{"name":"Journal of Operator Theory","volume":" ","pages":""},"PeriodicalIF":0.7000,"publicationDate":"2019-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":"{\"title\":\"Angular derivatives and compactness of composition operators on Hardy spaces\",\"authors\":\"Dimitrios Betsakos\",\"doi\":\"10.7900/JOT.2018APR18.2196\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Let Do be a simply connected subdomain of the unit disk and A be a compact subset of Do. Let φ be a universal covering map for Do \\\\ A. We prove that the composition operator Cφ is compact on the Hardy space H if and only if φ does not have an angular derivative at any point of the unit circle. This result extends a theorem of M.M. Jones.\",\"PeriodicalId\":50104,\"journal\":{\"name\":\"Journal of Operator Theory\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2019-07-28\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"1\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Operator Theory\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.7900/JOT.2018APR18.2196\",\"RegionNum\":4,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Operator Theory","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.7900/JOT.2018APR18.2196","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
Angular derivatives and compactness of composition operators on Hardy spaces
Let Do be a simply connected subdomain of the unit disk and A be a compact subset of Do. Let φ be a universal covering map for Do \ A. We prove that the composition operator Cφ is compact on the Hardy space H if and only if φ does not have an angular derivative at any point of the unit circle. This result extends a theorem of M.M. Jones.
期刊介绍:
The Journal of Operator Theory is rigorously peer reviewed and endevours to publish significant articles in all areas of operator theory, operator algebras and closely related domains.