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A generalization of Axiom A - MaRDI portal

A generalization of Axiom A (Q910398)

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scientific article; zbMATH DE number 4139722
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A generalization of Axiom A
scientific article; zbMATH DE number 4139722

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    A generalization of Axiom A (English)
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    1990
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    In ``Iterated forcing'' [Surveys in set theory, Lond. Math. Soc. Lect. Note Ser. 87, 1-59 (1983; Zbl 0524.03040)], \textit{J. E. Baumgartner} introduced Axiom A forcing. Iterated Axiom A forcing with countable support has the following important covering property: If \(X^ 0\) is a countable set of ordinals in the generic extension, then there is a countable set X in the ground model with \(X^ 0\subseteq X\). It is not known if the iteration itself satisfies Axiom A. Here the author presents a generalization of Axiom A forcing, the Axiom C forcing, which has the above covering property and is preserved under countable support iteration.
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    fusion sequence
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    iterated forcing
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    covering property
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    Axiom C forcing
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    countable support iteration
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