On the stability of limit cycles for planar differential systems

Hector Giacomini, Maite Grau

We consider a planar differential system $\dot{x}=P(x,y)$, $\dot{y}=Q(x,y)$, where $P$ and $Q$ are ${\mathcal{C}}^1$ functions in some open set $\mathcal{U} \subseteq \mathbb{R}^2…