Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Elliptic solutions of isentropic ideal compressible fluid flow in (3+1)
  dimensions
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph