Diagram showing the regions where the bifurcation is direct as well as those regions where it is inverse. The x-axis shows the values of the third coefficient of the Taylor expansion Equation (6), and the y-axis is the difference between the admittance amplitude between the two first resonances (assumed to be harmonic) Y₂ −Y₁ = 1/Z₂ − 1/Z₁. The hatched region is for a direct bifurcation, and the unhatched region for an inverse bifurcation. Adapted from [26].