Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The homotopy analysis method and the Lienard equation   In this work, Lienard equations are considered. The limit cycles of these
systems are studied by applying the homotopy analysis method. The amplitude and
frequency obtained with this methodology are in good agreement with those
calculated by computational methods. This puts in evidence that the homotopy
analysis method is an useful tool to solve nonlinear differential equations.

35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org