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ZFC existence of a countable Fréchet–Urysohn space with π-weight equal to 𝔟

Determine, within ZFC, whether there exists a countable Fréchet–Urysohn topological space whose π-weight is exactly the bounding number 𝔟.

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Background

The paper constructs countable Hausdorff 0-dimensional Fréchet–Urysohn spaces that are not H-separable under the assumptions b=c\mathfrak b=\mathfrak c and p=b\mathfrak p=\mathfrak b, and derives a corollary under cω2\mathfrak c \leq \omega_2. These results control the π-weight in those models, but leave open what can be proved in ZFC without additional set-theoretic assumptions.

The authors explicitly note that the corollary is included because the ZFC status of whether a countable Fréchet–Urysohn space can have π-weight exactly b\mathfrak b is unknown. Resolving this would clarify the optimal π-weight achievable in ZFC for such spaces.

References

Corollary \ref{cor} is included because it is not known if, in ZFC, there is a countable Fr echet-Urysohn space with $\pi$-weight exactly $\mathfrak b$.

New examples in the study of selectively separable spaces (2509.22590 - Dow et al., 26 Sep 2025) in Introduction, paragraph following Corollary \ref{cor}