Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Surface plasmons in metallic films of arbitrary thickness with mirror
  boundary conditions
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph