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- TL;DR
- Possible values of cardinality in different models of ZFC+ ~CH
Ok, so assume we have a model for ZFC where CH does not hold. What values may ##2^{\aleph_0}## assume over said models?
The discussion centers on the values that ##2^{\aleph_0}## can assume in models of ZFC where the Continuum Hypothesis (CH) does not hold. It references Solovay's result, which states that for any uncountable cardinal ##\kappa##, there exists a forcing extension where ##2^{\aleph_0} = \kappa##. Additionally, it highlights König's theorem, which establishes that it is inconsistent to assume ##2^{\aleph_0}## equals ##\aleph_{\omega}##, ##\aleph_{\omega_1+\omega}##, or any cardinal with cofinality ##\omega##.
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A result of Solovay, proved shortly after Cohen's result on the independence of the continuum hypothesis, shows that in any model of ZFC, if ##\kappa## is a cardinal of uncountable cofinality, then there is a forcing extension in which ##2^{\aleph_0} = \kappa##. However, per König's theorem, it is not consistent to assume ##2^{\aleph _{0}}## is ##\aleph _{\omega }## or ##\aleph _{\omega _{1}+\omega }## or any cardinal with cofinality ##\omega##.