Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Are Pions Perturbative in Effective Field Theory?   It is shown that pions can be included perturbatively into effective field
theory only for the external momenta, well below the pion mass. But for such
low energies it is not necessary to include pions explicitly.

26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ