Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Infinitely many periodic solutions for second order Hamiltonian systems   In this paper, we study the existence of infinitely many periodic solutions
for second order Hamiltonian systems $\ddot{u}+\nabla_u V(t,u)=0$, where $V(t,
u)$ is either asymptotically quadratic or superquadratic as $|u|\to \infty$.

0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
1
The categories of this paper are: cs