
The family \({\mathcal A}\) of some countable subsets of the infinite cardinal \(\kappa\) is said to be saturated (or completely separable) if for all subsets x of \(\kappa\) either there is \(a\in {\mathcal A}\) with \(a\subseteq x\) or else there are finitely many sets \(a_ 1,...,a_ n\in {\mathcal A}\) with \(x-(a_ 1\cup...\cup a_ n)\) finite. Let S(\(\kappa\)) be the statement: there exists an infinite, almost disjoint, saturated family of countable subsets of the cardinal \(\kappa\). The existence of saturated families is a long-standing problem in set theory. In the early seventies Baumgartner showed that \(\forall nS(\aleph_ n)\) is a consequence of the Continuum Hypothesis. Later, \textit{A. Hajnal, I. Juhász} and \textit{L. Soukup} [Comment. Math. Univ. Carol. 28, 629-633 (1987; Zbl 0648.03034)] produced a forcing model to show the relative consistency of \(\forall \kappa S(\kappa)\). In this paper, the authors show that \(\forall \kappa S(\kappa)\) is a consequence of \(V=K\), where K is the core model. (In fact, they give more technical conditions under which their induction will go through.)
core model, saturated families of countable subsets of infinite cardinals, Other combinatorial set theory
core model, saturated families of countable subsets of infinite cardinals, Other combinatorial set theory
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