Abstract
We study the set sp(i)={|A|:A⊆[ω]ω is a maximal independent family}, referred to as the spectrum of independence. We develop a forcing notion, which allows us to adjoin a maximal independent family of arbitrary cardinality, and so in particular of cardinality ℵω. Moreover, given an arbitrary set Θ of uncountable cardinals, our techniques allow to obtain a cardinal preserving generic extension in which Θ⊆sp(i), thus showing that sp(i) can be arbitrarily large. For finite Θ, as well as certain countably infinite Θ, we can obtain a precise equality, i.e. models of sp(i)=Θ.
Original language | English |
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Article number | 103161 |
Journal | Annals of Pure and Applied Logic |
Volume | 173 |
Issue number | 9 |
DOIs | |
State | Published - 1 Oct 2022 |
Bibliographical note
Publisher Copyright:© 2022 The Author(s)
Keywords
- Combinatorial cardinal characteristics
- Consistency
- Independent families
- Spectrum