Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The Barut Second-Order Equation: Lagrangian, Dynamical Invariants and
  Interactions
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph