Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The Magnetoelastic Distortion of Multiferroic BiFeO$_3$ in the Canted
  Antiferromagnetic State
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc