Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Near-integrability of low dimensional periodic Klein-Gordon lattices   The low dimensional periodic Klein-Gordon lattices are studied for
integrability. We prove that the periodic lattice with two particles and
certain nonlinear potential is non integrable. However, in the cases of up to
six particles, we prove that their Birkhoff-Gustavson normal forms are
integrable, which allows us to apply KAM theory.

29
The categories of this paper are: funct-an
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th