Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Centers with equal period functions   We give a sufficient condition for systems with symmetries to have periodic
solutions with equal periods. We show that the main result can be applied both
to Hamiltonian and to non-Hamiltonian systems. We apply the main results to
produce planar centers with equal period functions.

37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat