Products of spaces and the convergence of sequences
By the Hewitt–Marczewski–Pondiczery theorem, the Tychonoff product of $2^\omega$ separable spaces is separable. We continue to explore the problem of the existence in the Tychonoff product $\prod\limits_{\alpha\in 2^\omega}Z_\alpha$ of $2^\omega$ separable spaces a dense countable subset, which does...
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Veröffentlicht in: | Vestnik Udmurtskogo universiteta. Matematika, mekhanika, kompʹi͡u︡ternye nauki mekhanika, kompʹi͡u︡ternye nauki, 2023-12, Vol.33 (4), p.563-570 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | By the Hewitt–Marczewski–Pondiczery theorem, the Tychonoff product of $2^\omega$ separable spaces is separable. We continue to explore the problem of the existence in the Tychonoff product $\prod\limits_{\alpha\in 2^\omega}Z_\alpha$ of $2^\omega$ separable spaces a dense countable subset, which does not contain non-trivial convergent sequences. We say that a sequence $\lambda=\{x_n\colon n\in\omega\}$ is simple, if, for every $x_n\in\lambda$, a set $\{n'\in\omega\colon x_{n'}=x_n\}$ is finite. We prove that in the product of separable spaces $\prod\limits_{\alpha\in 2^\omega}Z_\alpha$, such that $Z_\alpha$ $(\alpha\in 2^\omega)$ contains a simple nonconvergent sequence, there is a countable dense set $Q\subseteq\prod\limits_{\alpha\in 2^\omega}Z_\alpha$, which does not contain non-trivial convergent in $\prod\limits_{\alpha\in 2^\omega}Z_\alpha$ sequences. |
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ISSN: | 1994-9197 2076-5959 |
DOI: | 10.35634/vm230402 |