Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Theoretical topics in spacetime-symmetry violations   The Lorentz- and CPT-violating Chern-Simons extension of electrodynamics is
considered. In the context of N=4 supergravity in four spacetime dimensions, it
is argued that cosmological solutions can generate this extension. Within
Chern-Simons electrodynamics, theoretical and phenomenological topics are
reviewed that concern the number of the remaining spacetime symmetries and the
vacuum Cherenkov effect, respectively.

12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex