XIONG Feng, HUANG Wentao. The lower bounds of limit cycles for three classes of Liénard systems[J]. Acta Scientiarum Naturalium Universitatis SunYatseni, 2018,57(6):154-161.
XIONG Feng, HUANG Wentao. The lower bounds of limit cycles for three classes of Liénard systems[J]. Acta Scientiarum Naturalium Universitatis SunYatseni, 2018,57(6):154-161. DOI: 10.13471/j.cnki.acta.snus.2018.06.021.
The problem of the number of limit cycles for three classes of Liénard systems
that is
(
m
n
)=(9
7)
(
m
n
)=(8
7) and (
m
n
)=(7
8)
are studied in the neighbourhood of the origin. The first ten
nine and nine singular point values for the corresponding accompany complex systems are calculated by using the computer algebra system
Mathematica
and the method of singular point values. Then
three kinds of Liénard system can generate at least ten
nine and nine limit cycles at the sufficiently small neighborhood of the origin respectively. And the exitence of limit cycle is proved by applying the Jacobian determinant method. It is the first time for giving the lower bound estimates for such systems