TITLE: A representation of $F_{\sigma\delta}$-ideals?
QUESTION [8 upvotes]: First some definitions. By $\mathcal P(\mathbb N)$ we denote the family of all subsets of $\mathbb N$ endowed with the metrizable separable topology generated by the countable base consisting of the sets $[A;B]=\{C\subset \mathbb N:C\cap B=A\}$ where $A,B$ run over finite subsets of $\mathbb N$.
A subfamily $\mathcal F\subset\mathcal P(\mathbb N)$ is called hereditary if for any sets $F\in\mathcal F$ each subset of $F$ belongs to $\mathcal F$.
An ideal on $\mathbb N$ is a hereditary subfamily $\mathcal I\subset \mathcal P(\mathbb N)$, closed under unions.
An ideal $\mathcal I$ on $\mathbb N$ is called an $F_{\sigma\delta}$-ideal if $\mathcal I=\bigcap_{n=1}^\infty\bigcup_{m=1}^\infty\mathcal K_{n,m}$ for some closed subsets $\mathcal K_{n,m}$ of the compact topological space $\mathcal P(\mathbb N)$.
Problem 1. Can each $F_{\sigma\delta}$-ideal $\mathcal I\subset\mathcal P(\mathbb N)$ be written as $\mathcal I=\bigcap_{n=1}^\infty\bigcup_{m=1}^\infty\mathcal K_{n,m}$ for some hereditary closed subsets $\mathcal K_{n,m}$ of the compact topological space $\mathcal P(\mathbb N)$?
We can ask also a more general
Problem 2. Can each hereditary $F_{\sigma\delta}$-set $\mathcal I\subset\mathcal P(\mathbb N)$ be written as $\mathcal I=\bigcap_{n=1}^\infty\bigcup_{m=1}^\infty\mathcal K_{n,m}$ for some hereditary closed subsets $\mathcal K_{n,m}$ of the compact topological space $\mathcal P(\mathbb N)$?
Problem 2 is a related to another open (?)
Problem 3. Does each Borel hereditary subset $\mathcal F\subset\mathcal P(\mathbb N)$ belong to the smallest subfamily of $\mathcal P(\mathbb N)$ containing all open hereditary sets and closed under taking countable unions and intersections?

REPLY [4 votes]: In [1], Solecki proved (Theorem 2.1 combined with Lemma 2.4),
Theorem:  $\mathcal{I} \subset \mathcal{P}(\mathbb{N})$ is an analytic P-ideal, if and only if, there is some $\varphi:\mathcal{P}(\mathbb{N})\rightarrow [0,\infty)$ satisfying the following,

$\varphi(\emptyset) = 0$,
$\varphi(A) \le \varphi(A \cup B) \le \varphi(A) + \varphi(B)$, and
$\varphi(A) = \lim_{n\rightarrow \infty} \varphi(A\cap n)$,

such that $\mathcal{I} = \{ A \subset \mathbb{N}: \limsup_{n} \varphi(A \backslash n)=0\}$. Furthermore, every analytic ideal on $\mathbb{N}$ is either a $P$-ideal, or finite-to-one reducible to the ideal generated by finite unions of the sets $\{ n\} \times \mathbb{N}.$
Remark: Any $\varphi$ which satisfies the hypothesis of the theorem is called a lower semi-continuous sub-measure on $\mathbb{N}$. 

An easy corollary to the previous theorem provides a partial answer to Problem 1.

Every $F_{\sigma\delta}$ $P$-ideal on $\mathbb{N}$ can be written as $\bigcap_n \bigcup_m K_{n,m}$ for some closed and hereditary $K_{n,m}$.

Proof: Using the previous theorem, it follows that for each $F_{\sigma\delta}$ P-ideal $\mathcal{I}$ there is a lower semi-continuous $\varphi$ such that $\mathcal{I} = \{ A \subset \mathbb{N} : \limsup_{n} \varphi(A\backslash n) = 0\}$. Letting $K_{n,m} = \{ A \subset \mathbb{N}: \varphi(A\backslash m) \le \frac{1}{n} \}$, we have $\mathcal{I} = \bigcap_n \bigcup_m K_{n,m}$; so it only remains to show that each $K_{n,m}$ is closed and hereditary. 
To this end note that, for each $A \in K_{n,m}$ and $B\subset A$ we have $B\backslash m \subset A\backslash m$, therefore using the properties of $\varphi$, it follows that, $\varphi(B\backslash m) \le \varphi(B\backslash m \cup A\backslash m)=\varphi(A\backslash m) \le \frac{1}{n}$ and so $B \in K_{n,m}.$
Next, assume $A \subset \mathbb{N}$ has the property that for every $k \in \mathbb{N}$ letting $a_k = A \cap k$ and $b_k =k$, we have $[a_k, b_k]\cap K_{n,m} \neq \emptyset$. Then, for every $k \ge 0$, $\varphi(a_k \backslash m) \le \frac{1}{n}$ (since the sequence is increasing.) It immediately follows that $\varphi(A \backslash m) = \lim_{k} \varphi(a_k \backslash m) \le \frac{1}{n}$ and $A \in K_{n,m}$.
[1] Solecki, Sławomir, Analytic ideals and their applications, Ann. Pure Appl. Logic 99, No.1-3, 51-72 (1999). ZBL0932.03060.