{"title":"无界严格奇异算子","authors":"R.W. Cross","doi":"10.1016/S1385-7258(88)80004-0","DOIUrl":null,"url":null,"abstract":"<div><p>Let <em>D(T)⊂X→Y</em> be an unbounded linear operator where <em>X</em> and <em>Y</em> are normed spaces. It is shown that if <em>Y</em> is complete then <em>T</em> is strictly singular if and only if <em>T</em> is the sum of a continuous strictly singular operator and an unbounded finite rank operator. A counterexample is constructed for the case in which <em>Y</em> is not complete.</p></div>","PeriodicalId":100664,"journal":{"name":"Indagationes Mathematicae (Proceedings)","volume":"91 3","pages":"Pages 245-248"},"PeriodicalIF":0.0000,"publicationDate":"1988-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1385-7258(88)80004-0","citationCount":"9","resultStr":"{\"title\":\"Unbounded strictly singular operators\",\"authors\":\"R.W. Cross\",\"doi\":\"10.1016/S1385-7258(88)80004-0\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Let <em>D(T)⊂X→Y</em> be an unbounded linear operator where <em>X</em> and <em>Y</em> are normed spaces. It is shown that if <em>Y</em> is complete then <em>T</em> is strictly singular if and only if <em>T</em> is the sum of a continuous strictly singular operator and an unbounded finite rank operator. A counterexample is constructed for the case in which <em>Y</em> is not complete.</p></div>\",\"PeriodicalId\":100664,\"journal\":{\"name\":\"Indagationes Mathematicae (Proceedings)\",\"volume\":\"91 3\",\"pages\":\"Pages 245-248\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"1988-09-26\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://sci-hub-pdf.com/10.1016/S1385-7258(88)80004-0\",\"citationCount\":\"9\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Indagationes Mathematicae (Proceedings)\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1385725888800040\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Indagationes Mathematicae (Proceedings)","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1385725888800040","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Let D(T)⊂X→Y be an unbounded linear operator where X and Y are normed spaces. It is shown that if Y is complete then T is strictly singular if and only if T is the sum of a continuous strictly singular operator and an unbounded finite rank operator. A counterexample is constructed for the case in which Y is not complete.