Fig. 4.

Minimal fraction Ω_min of spins that one has to flip to induce a transition from the all-spin-down to the all-spin-up pattern. All networks have N = 10⁵ vertices but differ in their degree distribution, which was Poissonian or scale-free with γ = 3.0, γ = 2.5, and γ = 2.1. The open squares were obtained from the analytical expression (Eq. 14); the filled squares were obtained through exact enumerations where each data point represents an average over 100 network realizations.