Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Dirac equation, hydrogen atom spectrum and the Lamb shift in dynamical
  noncommutative spaces
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin