Fig. 2

Bifurcation curves in the (k_1,k_2)-plane. {\tau }_1=11.6 and {\tau }_2=20.3. The right plot shows a detail of the first quadrant only. Blue shows the conditions for fold or transcritical bifurcations (Equations 14a and 14b) and red and magenta depict Hopf bifurcations; equations {\mathbf{h}}_{+} and {\mathbf{h}}_{-}, respectively. The gray area represents the stability region as in Corollary 4. The full stability region is hatched in the right diagram.