Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Geometric control condition for the wave equation with a time-dependent
  observation domain
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph