SIR Epidemic: Network vs Mean-Field Theory
S:
—
I:
—
R:
—
S (network)
I (network)
R (network)
S (MF)
I (MF)
R (MF)
Parameters
Nodes (N):
120
Avg degree (k):
6
Infection rate (β):
0.30
Recovery rate (γ):
0.10
R₀ = βk/γ:
—
Run Simulation
Reset
SIR model:
S→I at rate β per infected neighbor; I→R at rate γ.
Mean-field ODE:
dS/dt = −βkSI/N, dI/dt = βkSI/N − γI.
Epidemic threshold: R₀ = βk/γ > 1. Network heterogeneity causes deviations from mean-field predictions.