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Consequences of CMC(ℵ0,∞) or cf(ℵ1)=ℵ1 for P-space properties at uncountable κ

Determine whether either CMC(ℵ0,∞) or cf(ℵ1)=ℵ1 implies, for every uncountable well-ordered cardinal κ, that (a) both S_{P}(κ,[κ]^{≤ω}) and 2^{κ}[[κ]^{≤ω}] are P-spaces, or (b) S(κ,[κ]^{≤ω}) is a P-space.

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Background

Building on Theorem s5:t6, which shows certain implications from stronger assumptions, the authors highlight that it is currently unknown whether either the countable multiple choice principle CMC(ℵ0,∞) or the regularity of ℵ1 alone suffices to force the relevant P-space properties at all uncountable well-ordered cardinals κ.

References

Moreover, if $\kappa$ is any uncountable well-ordered cardinal, then it is also unknown if $\mathbf{CMC}(\aleph_{0},\infty)$ (or $\cf(\aleph_{1})=\aleph_{1}$) implies either of (ii) or (iii) of Theorem \ref{s5:t6}.

Constructing crowded Hausdorff $P$-spaces in set theory without the axiom of choice (2510.11935 - Tachtsis et al., 13 Oct 2025) in Section 5, Remark s5:r7