Center cyclicity of a family of quartic polynomial differential system

摘要

In this paper we study the cyclicity of the centers of the quartic polynomial family written in complex notation as [ = i z z (A z^2 B z C ^2 ),] where A,B,C C. We give an upper bound for the cyclicity of any nonlinear center at the origin when we perturb it inside this family. Moreover we prove that this upper bound is sharp.