Journal of Symbolic Logic
- J. Symbolic Logic
- Volume 72, Issue 4 (2007), 1228-1238.
There may be infinitely many near-coherence classes under 𝔲 < 𝔡
We show that in the models of 𝔲 < 𝔡 from  there are infinitely many near-coherence classes of ultrafilters, thus answering Banakh’s and Blass’ Question 30 of  negatively. By an unpublished result of Canjar, there are at least two classes in these models.
J. Symbolic Logic, Volume 72, Issue 4 (2007), 1228-1238.
First available in Project Euclid: 18 February 2008
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Mathematical Reviews number (MathSciNet)
Zentralblatt MATH identifier
Primary: 03E15: Descriptive set theory [See also 28A05, 54H05] 03E17: Cardinal characteristics of the continuum 03E35: Consistency and independence results 03D65: Higher-type and set recursion theory
Mildenberger, Heike. There may be infinitely many near-coherence classes under 𝔲 < 𝔡. J. Symbolic Logic 72 (2007), no. 4, 1228--1238. doi:10.2178/jsl/1203350784. https://projecteuclid.org/euclid.jsl/1203350784