ELI5: Explain Like I'm 5

Exponential map (Riemannian geometry)

The exponential map is like a magical map that helps us move from one place to another in a special kind of space called Riemannian geometry.

Imagine you are playing on a bouncy castle, but instead of jumping around in all directions, you can only move in a straight line going forward. This is kind of like what Riemannian geometry is like, where instead of moving in all directions, we can only move along a straight line called a geodesic.

The exponential map helps us figure out where we will end up if we start moving along a geodesic for a certain amount of time. It's like saying "if I jump forward 10 times on the bouncy castle, where will I end up?" The exponential map tells us the answer to this question in Riemannian geometry.

The reason why this map is called the "exponential" map is because it uses a mathematical function called the exponential function. This function helps us calculate where we will end up after jumping forward a certain number of times.

So, in summary, the exponential map is a special map that helps us move along geodesics in Riemannian geometry and figure out where we will end up after a certain amount of time using the magical power of the exponential function.