Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Possible nematic to smectic phase transition in a two-dimensional
  electron gas at half-filling
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn