Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Non-evident stability of a Dirac field in Schwarzschild-de Sitter
  spacetime
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
18
The categories of this paper are: econ
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci