When two subnetworks with different average natural frequencies, ω¯1 and ω¯2, are coupled with a sufficiently high coupling strength, they synchronize at a mean frequency of (ω¯1 + ω¯2)/2, as shown previously in Li et al. (2008) and Wu et al. (2012). Figure 5A shows the transient dynamics of coupled super-hub networks with ω¯1=4.3 and ω¯2=4.7. After inter-subnetwork coupling at t = 250 s, the two networks begin to interact, and the oscillating frequencies of their nodes gradually converge to 4.5.
