Δ-sets

Knight, R. W.

doi:10.1090/S0002-9947-1993-1196219-6

$\Delta$-sets
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Trans. Amer. Math. Soc. 339 (1993), 45-60 Request permission

Abstract:

A model of ${\text {ZFC}}$ is constructed in which there exists a subset of the Moore plane that is countably paracompact but not normal. The method used in the construction is forcing using uncountable sets of finite partial functions, ${\omega _1}$ and ${\omega _2}$ are shown to be preserved using a fusion lemma.

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