So, if one increases the control parameter μ from point A, the system will have stable trivial response which will suddenly vanish at point O as there is no stable state beyond this point. Hence, this is a dangerous bifurcation as the system may be subjected to catastrophic failure at this point. This bifurcation point is known as sub-critical pitchfork bifurcation.

Figure 4.2.4: Subcritical pitchfork bifurcation.