Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gravitational bending angle of light for finite distance and the
  Gauss-Bonnet theorem   We discuss a possible extension of calculations of the bending angle of light
in a static, spherically symmetric and asymptotically flat spacetime to a
non-asymptotically flat case. We examine a relation between the bending angle
of light and the Gauss-Bonnet theorem by using the optical metric. A
correspondence between the deflection angle of light and the surface integral
of the Gaussian curvature may allow us to take account of the finite distance
from a lens object to a light source and a receiver. Using this relation, we
propose a method for calculating the bending angle of light for such cases.
Finally, this method is applied to two examples of the non-asymptotically flat
spacetimes to suggest finite-distance corrections: Kottler (Schwarzschild-de
Sitter) solution to the Einstein equation and an exact solution in Weyl
conformal gravity.

8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex