Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A characterization of quaternionic projective space by the
  conformal-Killing equation
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
1
The categories of this paper are: cs
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th