ELI5: Explain Like I'm 5

De Rham's theorem

De Rham's Theorem basically says that, if you have some shape or thing in space, and you want to understand how it moves, twists, and turns, then you can look at its shape in a variety of different ways, and they will all tell you the same thing.

Imagine you have a ball of clay. You could look at it from the top and see it's round, or you could look at it from the side and see it's flat. You could even look at it from various 3D angles and see it takes on different shapes. But no matter how you look at it, it's still the same ball of clay.

Now imagine you want to understand the twists and turns of a shape in space like a loop of rope. You could study it by looking only at its length, or you could study it by looking at the way the rope twists with respect to the space around it. These two different ways of looking at the rope will tell you the same information; it's just a matter of how you choose to view it.

De Rham's Theorem says that this idea applies to all shapes and spaces. No matter how you choose to examine something, if you look at it enough different ways, you'll always come up with the same answers about its movements and twists. It's like having a map that tells you how to get to a place, but you can take different routes and still reach your destination.

So, to recap, De Rham's Theorem is a tool that helps mathematicians understand the movements and twists of shapes and spaces by looking at them from different angles, but they always end up with the same information, just like looking at a ball of clay in different ways.