\(H^{\infty}+BUC\) does not have the best approximation property (Q1070494)
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scientific article; zbMATH DE number 3935761
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | \(H^{\infty}+BUC\) does not have the best approximation property |
scientific article; zbMATH DE number 3935761 |
Statements
\(H^{\infty}+BUC\) does not have the best approximation property (English)
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1984
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Any closed algebra between \(H^{\infty}\) and \(L^{\infty}\) is called a Douglas algebra. The question had been raised of whether all Douglas algebras had the best approximation property. That is, given any Douglas algebra \({\mathcal D}\) and \(f\in L^{\infty}\) does there exist a \(g\in {\mathcal D}\) such that \(\| f-g\|_{\infty}=\inf \{\| f- g\|_{\infty}:g\in {\mathcal D}\}\). An example is given of such an algebra that does not have this property.
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Hardy space
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Douglas algebra
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best approximation property
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0.80746907
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0.8028098
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0.8006552
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0.80012167
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0.78752947
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