Dice Question Streamline Icon: https://streamlinehq.com

Distinguishing the cardinal characteristics of S_{I,ε} and E_{I,ε}

Determine whether there exists a model of ZFC in which, for some or for all pairs (I, ε) with I a partition of ω into finite nonempty intervals and ε ∈ ℓ^1_+, the covering numbers satisfy cov(E_{I,ε}) ≠ cov(S_{I,ε}), and likewise whether the uniformity numbers satisfy non(E_{I,ε}) ≠ non(S_{I,ε}).

Information Square Streamline Icon: https://streamlinehq.com

Background

Within ZFC the paper proves certain inequalities and, for many models, equalities between the corresponding additivity and cofinality of the layered ideals S_{I,ε} and E_{I,ε}. However, the relationships between their covering and uniformity characteristics remain subtle.

This question asks for forcing models that separate cov(E_{I,ε}) from cov(S_{I,ε}), and similarly separate non(E_{I,ε}) from non(S_{I,ε}), thereby clarifying the independence landscape for these new ideals.

References

We discuss some open questions from this study. With regard to~\autoref{cichonext} and items~\ref{cohen}-\ref{miller}, we do not know the following. Is it consistent that $(E_{I,\varepsilon})$ and $(S_{I,\varepsilon})$ are different for some (or for all) $I$ and $\varepsilon$? The same is asked for uniformities.

Cardinal characteristics associated with small subsets of reals (2405.11312 - Cardona et al., 18 May 2024) in Section Open Questions