Dependence on \(\aleph\) coordinates of separately continuous functions of many variables and its analogs (Q6165355)
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scientific article; zbMATH DE number 7707278
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | Dependence on \(\aleph\) coordinates of separately continuous functions of many variables and its analogs |
scientific article; zbMATH DE number 7707278 |
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Dependence on \(\aleph\) coordinates of separately continuous functions of many variables and its analogs (English)
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4 July 2023
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Let \(\aleph\) be an infinite cardinal and let \(X\) be the product of a family \((X_s\colon s\in S)\) of nontrivial completely regular spaces \(X_s\). It is known that every continuous function \(f\colon X\to\mathbb{R}\) depends on \(\aleph\) coordinates iff \(X\) is pseudo-\(\aleph^+\)-compact. Some necessary and sufficient conditions for the dependence on a certain number of coordinates of separately continuous functions of two or more variables on products were investigated in the last thirty years. In the present paper the author gives a new characterization for the (strongly) separately continuous function \(f\) defined on the product of nontrivial completely regular spaces to be dependent on \(\aleph\) coordinates (Theorem 5.5 and Corollary 5.6).
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separately continuous function
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quasicontinuous function
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dependence on countable many of coordinates
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compact space
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