Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Introduction to the Nonperturbative Renormalization Group   An elementary introduction to the non-perturbative renormalization group is
presented mainly in the context of statistical mechanics. No prior knowledge of
field theory is necessary. The aim is this article is not to give an extensive
overview of the subject but rather to insist on conceptual aspects and to
explain in detail the main technical steps. It should be taken as an
introduction to more advanced readings.

33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
19
The categories of this paper are: eess
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph