Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: On the approximability of the stable matching problem with ties of size
  two
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom