Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: About calculation of traces of Dirac $\gamma$-matrices contracted with
  massless vectors in Minkowski space
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat