Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Direct imaging of the structural domains in iron pnictides AFe2As2 (A =
  Ca, Sr, Ba)
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int