Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Are the spectra of geometrical operators in Loop Quantum Gravity really
  discrete?
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg