Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Introduction to effective field theories. 1. Heisenberg-Euler effective
  theory, decoupling of heavy flavours
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom