Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: KAM Theorem and Renormalization Group   We give an elementary proof of the analytic KAM theorem by reducing it to a
Picard iteration of a PDE with quadratic nonlinearity, the so called Polchinski
renormalization group equation studied in quantum field theory.

25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th