Owner: @Alexander Mozeika @David Rusu
When you are modelling the behaviour of a system compromised of many individual actors, you can sometimes apply the Large Mass Approximation as one way to gain insight into the behaviour of the system.
If the impact of some actor in your model is captured by some variable $w_i$, then you can take a physical interpretation of this system by imagining that these $w_i$’s are the masses of little particles, then $\sum w_i$ is the combined mass of all the particles in the system.
You can then analyze the behaviour of the system under the assumption that the masses of these little particles are very small relative to the total mass of the system.
The way this is done is you take a taylor expansion of the equation modelling your system at $\sum w_i=\infty$.
The result is an approximation of the original model which tells you how the system will behave when the total mass is very large relative to any individual actor.
These expanded equations are often simpler to work with than original equations.