This paper gives the equations as:
The fitness of cooperators and defectors is respectively given by fC = b(i − 1)/(N − 1) − c and fD = bi/(N − 1).
c - cost
b - benefit
i - number of cooperators
N - population size
For the equation
fC, does this mean
(b(i − 1)/(N − 1)) − c, i.e.:
b(i − 1)/((N − 1) − c), i.e.:
Guessing the former but I just want to check.
While we're at it, could someone explain why this is how fitness is modeled?