Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Forcing with ideals of closed sets   Let I be a sigma-ideal sigma-generated by a projective collection of closed
sets. The forcing with I-positive Borel sets is proper and adds a single real r
of an almost minimal degree: if s is a real in V[r] then s is Cohen generic
over V or V[s]=V[r].

22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat