Figure 2
From: Low-dimensional behavior of Kuramoto model with inertia in complex networks
Phases θ and frequencies 
vs natural frequencies Ω, which shows that phase-locked oscillators only exist in red area but not in the yellow area.
The read area indicates parameter combination of stable fixed point. Stable fixed points and limit cycles coexist in the yellow area. The white area represents the existence of limit cycles. The stationary value of the order parameter r could be calculated by simulations or Eq. (11). Thus nodes with natural frequencies between 
are synchronized. The boundary of bistable region are specified by |Ω| within 
.
