Bifurcation of limit cycles and pseudo-isochronicity at degenerate singular point in a septic system (Q968078)

This paper deals with the problems of limit cycle bifurcations and pseudo-isochronous center conditions at a degenerate singular point in a class of septic differential systems. The authors solve the problems by an indirect method, i.e., they transform the degenerate singular point into an elementary singular point. Then the authors construct a septic system which allows the appearance of eight limit cycles in the neighborhood of the degenerate singular point. Finally, they investigate the pseudo-isochronous center conditions at the degenerate singular point for the septic system.