Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Applications of Two Body Dirac Equations to Hadron and Positronium
  Spectroscopy
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat