ELI5: Explain Like I'm 5

Freidlin–Wentzell theorem

The Freidlin-Wentzell theorem is a special idea that helps us understand the way things move in the world around us. Imagine you are playing with a toy car and you push it from one place to another. Now imagine that, instead of you pushing the car, there's a tiny creature inside the car who's pushing it around by running on a treadmill.

The Freidlin-Wentzell theorem tells us that, in certain situations, this tiny creature's actions are just as important as the larger movements of the car. Specifically, it deals with the way things move when there's a lot of randomness involved. It tells us that, even if something seems to be bouncing around completely randomly, there can still be important patterns and structures hidden in that randomness.

For example, think about the way smoke rises. If you watch a plume of smoke coming off a fire, it seems to move in a completely chaotic way, swirling around and changing direction at random. But the Freidlin-Wentzell theorem says that, even in all that apparent randomness, there are still underlying patterns and structures that we can learn about and understand.

Overall, the Freidlin-Wentzell theorem helps us make sense of seemingly random movements in the world around us, showing us that there's often more order and structure than we might initially think.