Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Simulation of Panleve-Gullstrand black hole in thin 3He-A film   The quasi-stationary superfluid state is constructed, which exhibits the
event horizon and Hawking radiation.

6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph