The Machado-Bishop theorem in the uniform topology (Q6632945)
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scientific article; zbMATH DE number 7938836
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | The Machado-Bishop theorem in the uniform topology |
scientific article; zbMATH DE number 7938836 |
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The Machado-Bishop theorem in the uniform topology (English)
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5 November 2024
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The Machado-Bishop theorem for weighted vector-valued functions vanishing at infinity has been extensively studied. In this paper, giving an analogue of Machado's distance formula for bounded weighted vector-valued functions, the author studies the Machado-Bishop theorem for bounded weighted spaces in the uniform topology. Unlike in the weighted space \(CV_0 (\Omega , X)\), one cannot expect that Machado's distance formula holds in \(CV_b (\Omega, X)\) in the uniform topology, due to Hewitts counter-example [\textit{E. Hewitt}, Duke Math. J. 14, 419--427 (1947; Zbl 0029.30302)]. Instead, the author finds a formula like \(d_ {\Omega} (f, A) = \inf_{E\in \mathcal{A}} d_E (f, A)\) where \(\mathcal{A}\) is some ``simple'' z-filter. Some types of the Bishop-Stone-Weierstrass theorem for bounded vector-valued continuous spaces in the uniform topology are also discussed.
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Stone-Weierstrass theorem
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approximation
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weighted space
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extension
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tensor product
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