Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Fast estimation from above of the maximum wave speed in the Riemann
  problem for the Euler equations
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol