Perturbations from a kind of quartic Hamiltonians under general cubic polynomials

In this paper we investigate the perturbations from a kind of quartic Hamiltonians under general cubic polynomials. It is proved that the number of isolated zeros of the related abelian integrals around only one center is not more than 12 except the case of global center. It is also proved that there exists a cubic polynomial such that the disturbed vector field has at least 3 limit cycles while the corresponding vector field without perturbations belongs to the saddle loop case. This work was supported by National Natural Science Foundation of China (Grant No. 10671020)