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arXiv · 2605.21175

Forcing $\mathbfΣ^1_1$-Separation on $ω_1^{ω_1}$

Stefan Hoffelner
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Abstract

We prove that it is consistent that every two disjoint boldface $\mathbfΣ^1_1$ subsets of $ω_1^{ω_1}$ can be separated by a boldface $\mathbfΔ^1_1$ set. The forcing starts from $L$ and preserves CH and therefore also $ω_1^{<ω_1}=ω_1$.

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Stefan Hoffelner. 2026-05-20. Forcing $\mathbfΣ^1_1$-Separation on $ω_1^{ω_1}$. https://arxiv.org/abs/2605.21175

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