Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: PT-symmetry, ghosts, supersymmetry and Klein-Gordon equation   Parallels between the concepts of symmetry, supersymmetry and (recently
introduced) PT-symmetry are reviewed and discussed, with particular emphasis on
the new insight in quantum theory which is rendered possible by their combined
use.

33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
30
The categories of this paper are: q-alg