ELI5: Explain Like I'm 5

Rothe–Hagen identity

The Rothe-Hagen identity is a very fancy way of saying something that's actually quite simple! It's like when you learn a big word that means something you already knew, like "photosynthesis" for how plants make food.

In math, we use symbols like "+" and "-" to do things like add and subtract numbers. The Rothe-Hagen identity is a rule that helps us do something called "commutativity" with these symbols. "Commutativity" just means that when we do an operation (like adding or subtracting), the order of the things we're doing it to doesn't matter.

For example, if we have 2 + 3, we can also write it as 3 + 2, and it still gives us the same answer (5). That's commutativity in action!

But sometimes we have more complicated things than just numbers, like variables or functions. The Rothe-Hagen identity helps us deal with commutativity when we're working with these more complex things. It's a rule that says that no matter what variables or functions we're working with, if we add them together in a certain way, we'll get the same answer no matter what order we add them in.

It might feel a little complicated, but really it's just a helpful tool for doing math that makes sure we get the right answer every time. So the next time you see the Rothe-Hagen identity, just remember that it's like the word "photosynthesis" - something that sounds fancy, but is actually a simple way to explain something we already know!