Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Numerical reconstruction of radiative sources in an absorbing and
  non-diffusing scattering medium in two dimensions
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an