Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Ab initio determination of excitation energies and magnetic couplings in
  correlated, quasi two-dimensional iridates
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org