Fig. 5From: Fast–Slow Bursters in the Unfolding of a High Codimension Singularity and the Ultra-slow Transitions of ClassesPhase flows. For each region of the unfolding, labeled with a Roman numeral in Fig. 4, we show the nullclines of Eq. (2) in light and dark purple. Fixed points at the intersection of the nullclines are marked with yellow dots. Flows are shown in blue. Nullclines and fixed points are computed analytically, flows are obtained through numerical simulations in MatcontBack to article page