Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: alpha^2 corrections to parapositronium decay
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ