Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Production of two hard isolated photons in
  $e^+e^-\to\mu^+\mu^-\gamma\gamma$ at LEP
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an