Limit cycles near an eye-figure loop in some polynomial Liénard systems.

In this paper, we study the number of limit cycles in the family d H − ε ω = 0 , where H = y 2 2 − ∫ 0 x g ( u ) d u , ω = y f ( x ) d x , with g ( x ) = x ( x 2 − 1 ) ( x 2 − 1 4 ) 2 , and f ( x ) an even polynomial of degree 10. We will consider mainly the bifurcation of limit cycles near the eye-figure loop and the center of d H = 0 . Our investigation focuses on the lower bound of the maximal number of limit cycles for these systems. In particular, we show that the perturbed system can have at least 8 limit cycles when deg ⁡ ( f ( x ) ) = 10 . [ABSTRACT FROM AUTHOR]