Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The ratio of N(C18O) and Av in Chamaeleon I and III-B using 2MASS and
  SEST
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con