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JOURNALS // Vestnik Udmurtskogo Universiteta. Matematika. Mekhanika. Komp'yuternye Nauki // Archive

Vestn. Udmurtsk. Univ. Mat. Mekh. Komp. Nauki, 2023 Volume 33, Issue 4, Pages 563–570 (Mi vuu868)

MATHEMATICS

Products of spaces and the convergence of sequences

A. A. Gryzlov, R. A. Golovastov, E. S. Bastrykov

Udmurt State University, ul. Universitetskaya, 1, Izhevsk, 426034, Russia

Abstract: 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.

Keywords: Tychonoff product, dense set, convergent sequence, independent matrix

UDC: 515.122

MSC: 54A25, 54B10

Received: 11.07.2023
Accepted: 01.11.2023

Language: English

DOI: 10.35634/vm230402



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© Steklov Math. Inst. of RAS, 2024