Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A New Numerical Algorithm for Thermoacoustic and Photoacoustic
  Tomography with Variable Sound Speed   We present a new algorithm for reconstructing an unknown source in
Thermoacoustic and Photoacoustic Tomography based on the recent advances in
understanding the theoretical nature of the problem. We work with variable
sound speeds that might be also discontinuous across some surface. The latter
problem arises in brain imaging. The new algorithm is based on an explicit
formula in the form of a Neumann series. We present numerical examples with
non-trapping, trapping and piecewise smooth speeds, as well as examples with
data on a part of the boundary. These numerical examples demonstrate the robust
performance of the new algorithm.

18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th