{"title":"实际分析","authors":"Prelim Workshop, Uc Berkeley","doi":"10.2307/j.ctt130hk3w.9","DOIUrl":null,"url":null,"abstract":"3. Since Lp and Lr are subspaces of CX , their intersection is a vector space. It is clear that ‖ · ‖ is a norm (this follows directly from the fact that ‖ · ‖p and ‖ · ‖r are norms). Let 〈fn〉n=1 be a Cauchy sequence in Lp ∩ Lr. Since ‖fm − fn‖p ≤ ‖fm − fn‖ and ‖fm − fn‖r ≤ ‖fm − fn‖ for all m,n ∈ N, it is clear that 〈fn〉n=1 is a Cauchy sequence in both Lp and Lr. Let gp ∈ Lp and gr ∈ Lr be the respective limits of this sequence. Given ε ∈ (0,∞), there exists N ∈ N such that ‖fn − gp‖p < ε(p+1)/p for all n ∈ N with n ≥ N. If n ∈ N and n ≥ N","PeriodicalId":222708,"journal":{"name":"Mathemagics: A Magical Journey Through Advanced Mathematics","volume":"41 37","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2020-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"3","resultStr":"{\"title\":\"Real Analysis\",\"authors\":\"Prelim Workshop, Uc Berkeley\",\"doi\":\"10.2307/j.ctt130hk3w.9\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"3. Since Lp and Lr are subspaces of CX , their intersection is a vector space. It is clear that ‖ · ‖ is a norm (this follows directly from the fact that ‖ · ‖p and ‖ · ‖r are norms). Let 〈fn〉n=1 be a Cauchy sequence in Lp ∩ Lr. Since ‖fm − fn‖p ≤ ‖fm − fn‖ and ‖fm − fn‖r ≤ ‖fm − fn‖ for all m,n ∈ N, it is clear that 〈fn〉n=1 is a Cauchy sequence in both Lp and Lr. Let gp ∈ Lp and gr ∈ Lr be the respective limits of this sequence. Given ε ∈ (0,∞), there exists N ∈ N such that ‖fn − gp‖p < ε(p+1)/p for all n ∈ N with n ≥ N. If n ∈ N and n ≥ N\",\"PeriodicalId\":222708,\"journal\":{\"name\":\"Mathemagics: A Magical Journey Through Advanced Mathematics\",\"volume\":\"41 37\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2020-05-18\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"3\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Mathemagics: A Magical Journey Through Advanced Mathematics\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.2307/j.ctt130hk3w.9\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Mathemagics: A Magical Journey Through Advanced Mathematics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.2307/j.ctt130hk3w.9","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
3. Since Lp and Lr are subspaces of CX , their intersection is a vector space. It is clear that ‖ · ‖ is a norm (this follows directly from the fact that ‖ · ‖p and ‖ · ‖r are norms). Let 〈fn〉n=1 be a Cauchy sequence in Lp ∩ Lr. Since ‖fm − fn‖p ≤ ‖fm − fn‖ and ‖fm − fn‖r ≤ ‖fm − fn‖ for all m,n ∈ N, it is clear that 〈fn〉n=1 is a Cauchy sequence in both Lp and Lr. Let gp ∈ Lp and gr ∈ Lr be the respective limits of this sequence. Given ε ∈ (0,∞), there exists N ∈ N such that ‖fn − gp‖p < ε(p+1)/p for all n ∈ N with n ≥ N. If n ∈ N and n ≥ N