Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Opinions and dark energy: A mechanism of long-range repulsion in a toy
  opinion particle model
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc