Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A metallic phase in lightly doped La$_{2-x}$Sr$_{x}$CuO$_{4}$ observed
  by electron paramagnetic resonance
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs