Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Some comments on calculations of the scalar radius of the pion and the
  chiral constant $\bar{l}_4$
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con