Figure 7. Triangle plots illustrating the population dynamics for defectors (
), cooperators (
) and loners (
) for trajectories starting from all possible initial frequencies for the inverse-sigmoidal risk removal pattern.
Each vertex represents a homogeneous population of that pure strategy. 
For small interest rate 
, all orbits starting from the inside area of 
converge to 
. 
Moderate 
delimits the inside area into two attraction basins. The equilibrium 
, a coexistence state of cooperators and defectors, accounts a relatively large area as its attraction basin. The rest of the inside area is the loner's attraction basin. 
Further increase in 
makes the 
coincide with 
and its attraction area spreads almost the whole inside area. Relevant parameters 
, 
and 
, 
, 
.