Be$\def\cube{\mathbf Q}$Let $\mathbb{Q}$$\cube$ be the Hilbert cube. Give an example of a closed subset $B$ of $\mathbb{Q}$$\cube$ such that $Int(B) = \emptyset$$\operatorname{Int}(B) = \emptyset$ and $B$ is not a z-set.
If anyone has any idea to solve this problem, it would help me a lot. I write down some information:
$\mathbf{Def.}$Definition. Let $\mathbb{Q}$ Hilbert Cube ($\mathbb{Q}= \prod_{n=1}^{\infty} [0,1]$$\cube= \prod_{n=1}^{\infty} [0,1]$ with product topology) with metrid, with metric $d$ such that if $(x_n)_n, (y_n)_n \in \mathbb{Q}$$(x_n)_n, (y_n)_n \in \cube$, $d((x_n)_n,(y_n)_n) = \sum_{n=1}^{\infty} \frac{|x_n - y_n|}{2^n}$$d((x_n)_n,(y_n)_n) = \sum_{n=1}^{\infty} \frac{\lvert x_n - y_n\rvert}{2^n}$. Then $B \subseteq \mathbb{Q}$$B \subseteq \cube$ is a z-set of $\mathbb{Q}$ if for, for each $\epsilon > 0$, there is a continuous function, $f_\epsilon$ from $\mathbb{Q}$$\cube$ to $\mathbb{Q} \setminus B$$\cube \setminus B$ such that $d(f_\epsilon(x),x) \ < \epsilon$$d(f_\epsilon(x),x) < \epsilon$ for all $x \in X$.
I have tried the following:
$\mathbf{Lemma.}$ If $B \subseteq \mathbb{Q}$ is, where a $\sigma$z-set ($\sigma$z-set is a countable union of Zz-sets. In (In $\mathbb{Q}$$\cube$, I think that all $\sigma$z-setsets are z-sets.)
Lemma. If $B \subseteq \cube$ is a z$\sigma$z-set), then $\mathbb{Q} \setminus B$$\cube \setminus B$ is a topologically complete, separable metric AR (Absolute Retract).
$\mathbf{Note.}$Note. In $\mathbb{Q}$$\cube$, $B \subseteq \mathbb{Q}$ Retract$B'$ being a retract is equivalent to $B$ is$B'$ being AR.
Then, I have tried to find an example of a $B \subseteq \mathbb{Q}$$B \subseteq \cube$ such that $\mathbb{Q} \setminus B$$\cube \setminus B$ is not a Retract, and then, for Lemmaretract. By the lemma, this $B$ would not be a $\sigma$z-set and then. Then check if this set $B$ havehas empty interior in $Q$$\cube$ and is closed. I could not find it.
$\mathbf{Note 2.}$ This is my first post. So excuse me if I broke any rule or something similar in the forum when writing the question. Thanks <3such a $B$.
References.
[1] Alejandro Wanes, Sam Nadler Jr. HYPERSPACES: Fundamental and Recent Advances.