Consider the following statement (in $\mathsf{ZF}+\text{AC}_\omega (\mathbb{R})$):
There exists $(C_\alpha, x_\alpha)_{\alpha \in \omega_1}$ s.t. $C_\alpha \subseteq \mathbb{N}^\mathbb{N}$ is closed and $\text{CB}^\alpha(C_\alpha) = \{x_\alpha\}$
where $\mathbb{N}^\mathbb{N}$ is the Baire space (the space of infinite sequences of natural numbers) with the usual topology and $\text{CB}^\alpha$ is the $\alpha$-th Cantor-Bendixon derivative.
My questions are:
- How much choice do we need at least to prove this statement? Or more generally what known weak axiom can be assumed (on top of $\mathsf{ZF}+\text{AC}_\omega (\mathbb{R})$) to prove the statement?
- Is it consisent $\mathsf{ZF}+\text{AC}_\omega (\mathbb{R}) + \neg$The above statement?
- If we assume the consistency of $\mathsf{ZF}+\mathsf{AD}$, is it consistent $\mathsf{ZF}+\mathsf{AD}\ +$ The above statement?
Thanks!