Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gravitational fields with sources, regular black holes, quasiblack
  holes, and analogue black holes   We discuss recent developments in gravitational fields with sources, regular
black holes, quasiblack holes, and analogue black holes, related to the talks
presented at the corresponding Parallel Session AT3 of the 13th Marcel
Grossmann Meeting.

16
The categories of this paper are: stat
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga