Figure 18.
Mean field social heterogeneity (MFSH) model. The flow diagram for a MFSH population (expected degree formulation). This is similar to the actual degree formulation in figure 6. The new variables ΠS, ΠI and ΠR (bottom, b) represent the probability that a newly formed edge connects to a susceptible, infected or recovered node; they can be thought of as the relative rates at which each group forms edges. As the test node does not cause infections, and the probability that a partnership is with a node of a given κ is equal to the probability that a new partner will be with a node of the given κ, the probability that a current partner has a given state is equal to the probability that a new partner has that state. Thus each Φ variable equals the corresponding Π variable. (Online version in colour.)