{"title":"Saphar张量积中$c_0(\\tau)$的副本","authors":"Vinícius Morelli Cortes","doi":"10.7146/math.scand.a-132282","DOIUrl":null,"url":null,"abstract":"Let $X, Y$ be Banach spaces, τ an infinite cardinal and $1 \\leq p < \\infty $. We extend a result by E. Oja by showing that if $X$ has a boundedly complete unconditional basis and either $X \\widehat{\\otimes}_{g_p} Y$ or $X \\widehat{\\otimes}_{\\varepsilon _p} Y$ contains a complemented copy of $c_0(\\tau )$, then $Y$ contains a complemented copy of $c_0(\\tau )$. We show also that if α is a uniform crossnorm, $X \\widehat{\\otimes}_\\alpha Y$ contains a (complemented) copy of $c_0(\\tau )$ and the cofinality of τ is strictly greater than the density of $X$, then $Y$ also contains a (complemented) copy of $c_0(\\tau )$. As an application, we obtain a result concerning complemented copies of $\\ell _1(\\tau )$ in $X \\widehat{\\otimes}_\\alpha Y$.","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Copies of $c_0(\\\\tau)$ in Saphar tensor products\",\"authors\":\"Vinícius Morelli Cortes\",\"doi\":\"10.7146/math.scand.a-132282\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Let $X, Y$ be Banach spaces, τ an infinite cardinal and $1 \\\\leq p < \\\\infty $. We extend a result by E. Oja by showing that if $X$ has a boundedly complete unconditional basis and either $X \\\\widehat{\\\\otimes}_{g_p} Y$ or $X \\\\widehat{\\\\otimes}_{\\\\varepsilon _p} Y$ contains a complemented copy of $c_0(\\\\tau )$, then $Y$ contains a complemented copy of $c_0(\\\\tau )$. We show also that if α is a uniform crossnorm, $X \\\\widehat{\\\\otimes}_\\\\alpha Y$ contains a (complemented) copy of $c_0(\\\\tau )$ and the cofinality of τ is strictly greater than the density of $X$, then $Y$ also contains a (complemented) copy of $c_0(\\\\tau )$. As an application, we obtain a result concerning complemented copies of $\\\\ell _1(\\\\tau )$ in $X \\\\widehat{\\\\otimes}_\\\\alpha Y$.\",\"PeriodicalId\":0,\"journal\":{\"name\":\"\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0,\"publicationDate\":\"2022-12-04\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.7146/math.scand.a-132282\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.7146/math.scand.a-132282","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Let $X, Y$ be Banach spaces, τ an infinite cardinal and $1 \leq p < \infty $. We extend a result by E. Oja by showing that if $X$ has a boundedly complete unconditional basis and either $X \widehat{\otimes}_{g_p} Y$ or $X \widehat{\otimes}_{\varepsilon _p} Y$ contains a complemented copy of $c_0(\tau )$, then $Y$ contains a complemented copy of $c_0(\tau )$. We show also that if α is a uniform crossnorm, $X \widehat{\otimes}_\alpha Y$ contains a (complemented) copy of $c_0(\tau )$ and the cofinality of τ is strictly greater than the density of $X$, then $Y$ also contains a (complemented) copy of $c_0(\tau )$. As an application, we obtain a result concerning complemented copies of $\ell _1(\tau )$ in $X \widehat{\otimes}_\alpha Y$.