Have you ever tried to roll a toy car down a hill and watched how it moves? Well, the Carathéodory–Jacobi–Lie theorem is like a rule that tells us how things like toy cars move.
It starts with something called a "manifold," which is like a big piece of paper that you can fold and bend in all sorts of ways. This "manifold" is supposed to represent the space that the toy car moves in.
The theorem says that, if we know how the toy car is moving at one point on the manifold, we can use that information to figure out how it will move everywhere else on the manifold. We do this by using some special math called "differential equations."
Think of it like this: if you know that the toy car is moving forward at a certain speed, you can use the Carathéodory–Jacobi–Lie theorem to figure out where it will be in one minute, two minutes, three minutes, and so on. This can help you predict and control how the toy car moves.
So, the Carathéodory–Jacobi–Lie theorem is like a really fancy way to figure out how things move on a big piece of paper that we can bend and fold in all sorts of ways.