Mean Field Approach
Fitness landscapes in biology are often over a discrete (sequence, traint, or niche) space (not Euclidean)
The mean-field limit is obtained by considering the complete graph
While are random variables (distributions), in the large N limit is a number, leading to
The probability distribution functions for evolve according to the Fokker-Planck equation
[Van den Broeck+Parrondo+Amero+Hernandez-Machado (1994); ....]
The (unnormalized) steady-state solution has the form [PRE 102, 052106 (2020)]
A combination of power-laws with cutoffs at small and large values.