Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Dynamics and Afterglow Light Curves of GRB Blast Waves Encountering a
  Density Bump or Void
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex