Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Analytic structure factors and pair-correlation functions for the
  unpolarized homogeneous electron gas
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th