Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Comparison of particle properties in Kerr metric and in rotating
  coordinates   Properties of particles in Kerr metric are compared with properties of
particles in rotating coordinates in Minkowski space-time. It is shown that
particles with negative and zero energies existing in the ergosphere of the
rotating black hole also exist in the region out of the static limit in
rotating coordinates in Minkowski space-time. Some similarities like the
Penrose process and differences in both cases are analyzed.

35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph