Darboux-type center conditions for families of planar polynomial vector fields

Abstract

We study the center-focus problem for planar polynomial vector fields, which can be viewed as a local version of Hilbert's 16th problem. Based on a Lyapunov function approach, we establish novel results regarding the center-focus conditions for two families of differential systems. More precisely, we find an enclosure of the Bautin ideal generated by the Lyapunov constants of these systems. Our results hold for any degree $n\ge 2$.