N coupled oscillators dθᵢ/dt = ωᵢ + (K/N)Σ sin(θⱼ−θᵢ) undergo a phase transition at K_c = 2/πg(0) where g(ω) is the frequency distribution. The order parameter r = |⟨e^{iθ}⟩| jumps from 0 (incoherent) to finite (synchronized) — a mean-field bifurcation.