Authors: Dumitru Cozma
– 0.20 Mb
Abstract
For cubic differential systems with a bundle of two invariant straight lines and one invariant conic it is proved that a weak focus is a center if and only if the first four Liapunov quantities $L_j,\;j=\overline{1,4}$, vanish.E-mail:
Fulltext
– 0.20 Mb
