Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Superconductivity and antiferromagnetism in the two-dimensional Hubbard
  model: a variational study
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess