Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Looking for energy in demographic data; how to detect self-organization
  in human population distribution
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
37
The categories of this paper are: supr-con