Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A general space-time model for combinatorial optimization problems (and
  not only)
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph