Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The Phantom of the OPRA
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin