Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A spectral method for integral formulations of medium-frequency
  scattering problems   A fast method for the computation of layer potentials that arise in acoustic
scattering is introduced. The principal idea is to split the singular kernel
into a smooth and a local part. The potential due to the smooth part is
computed efficiently using non-equispaced FFTs, the potential due to the local
part is expanded as a series in the mollification parameter. The complexity of
the approach is shown to be $O(n + \kappa^3 \log \kappa)$, where $n$ is the
number of degrees of freedom in the discretization and $\kappa$ is the wave
number. The constant factor in this asymptotic estimate is small since no
singular surface integrals must be computed. Therefore the method is
particularly efficient for medium-sized scatterers (50-100 wavelengths) that
may have complicated geometry

29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc