Resolution:
## Figure 1.
Variable carrying capacity.(
a): A community where the carrying capacity is an increasing function of altruist number,
varying from N_{i} when the population is composed only of selfish individuals to N_{f} (N_{f} > N_{i}) when only altruists are present. (b) Two examples of random walks describing the stochastic behavior a such a system
(transition probabilities 4–7), where m,n are the number of selfish and altruistic individuals. Red line: loss of S’s; Blue line: loss of A. A Moran process in this scheme corresponds to a random walk constrained to remain
on an anti-diagonal line.
Houchmandzadeh and Vallade |