Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Lensing effect of a cosmic string in Chern-Simons gravity   It is pointed out that any conformally transformed of a flat space-time
metric $\ball g_{ij} = f(x)\;\eta_{ij}$ is a solution to Witten's equation of
Chern-Simons gravity, which holds outside matter in (2+1) dimensions. It is
also shown that a simultaneous exterior solution to both Witten's and
Einstein's equations, yields the lensing effect of an isolated cosmic string,
if $f(x)$ is reduced to an arbitrary dimensionless constant. However, the
solution to Witten's equation with $f(x)$ being an arbitrary and continuous
function of space-time coordinates, also leads to an open circular path for a
light ray near the string.

25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
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
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio