Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: On ultraproducts of Boolean Algebras and irr
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ