Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Unusual superexchange pathways in a Ni triangular lattice of
  NiGa$_2$S$_4$ with negative charge-transfer energy
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org