Equilibrium surface in (x,α,μ) space and sectionsβ₁andβ₂(the solid and dashed curves represent the stable and unstable branches, respectively). (a) Equilibrium surface. Panels (b) and (c) show center-saddle bifurcation inx–αplane (sectionβ₁) forμ= 0.1 and inx–μplane (sectionβ₂) forα= 0.4, respectively.