Abstract
We prove that:
I. For every regular Lindelöf space X if \(|X|=\Delta(X)\) and \(\mathrm{cf}|X|\ne\omega\), then X is maximally resolvable;
II. For every regular countably compact space X if \(|X|=\Delta(X)\) and \({\mathrm{cf}|X|=\omega}\), then X is maximally resolvable.
Here \(\Delta(X)\), the dispersion character of X, is the minimum cardinality of a nonempty open subset of X.
Statements I and II are corollaries of the main result: for every regular space X if \(|X|=\Delta(X)\) and every set \(A\subseteq X\) of cardinality \(\mathrm{cf}|X|\) has a complete accumulation point, then X is maximally resolvable.
Moreover, regularity here can be weakened to \(\pi\)-regularity, and the Lindelöf property can be weakened to the linear Lindelöf property.
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The author is grateful to Maria A. Filatova for constant attention to this work and to Vladislav R. Smolin and Vladimir V.Ivchenko for their help with editing.
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The work was performed as part of research conducted in the Ural Mathematical Center with the financial support of the Ministry of Science and Higher Education of the Russian Federation (Agreement number 075-02-2023-913).
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Lipin, A.E. Resolvability and complete accumulation points. Acta Math. Hungar. 170, 661–669 (2023). https://doi.org/10.1007/s10474-023-01358-y
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DOI: https://doi.org/10.1007/s10474-023-01358-y