ELI5: Explain Like I'm 5

Dedekind–Kummer theorem

The Dedekind-Kummer theorem is a really, really cool math secret that helps us understand how numbers work when we're trying to solve problems with equations.

Imagine if you had a big math problem like 2+2+2+2+2+2+2+2+2+2 and you wanted to find an easy way to write it all out. You could say that it's the same as 2 times 10. This is called a factorization.

The Dedekind-Kummer theorem is all about factorization, but with more complicated numbers called algebraic numbers. Now, what are algebraic numbers, you may ask? Well, they're kind of like regular numbers, but they come from solving really big math problems called equations.

So, the theorem tells us that if we have an algebraic number, we can break it down into smaller parts and write it as multiplication (just like 2 times 10). But the cool thing about this theorem is that it tells us exactly how to break down the algebraic number into those smaller parts.

Let's take the number 7 as an example. We know that 7 is a prime number, which means that it can't be written as a product of smaller numbers (like 2 times 3). But in the world of algebraic numbers, 7 can actually be broken down into smaller parts. The Dedekind-Kummer theorem tells us exactly how to do this by using something called a field extension (which is like adding some new numbers to our regular numbers).

So, long story short, the Dedekind-Kummer theorem tells us how to take apart really complicated numbers we get from solving math problems and break them down into smaller parts that are easier to use in other equations. Cool, huh?