ELI5: Explain Like I'm 5

Localization (commutative algebra)

Localization in commutative algebra is like taking a cake and cutting out just a small slice of it to focus on. Imagine you have a cake with different colored sprinkles on it. Each sprinkle represents a number or element in a mathematical concept called a ring.

Now let's say you want to only look at the red sprinkles in the cake. You can do this by cutting out just a small piece of the cake that has only the red sprinkles on it. This small piece is called a localization of that ring, and it's a new smaller ring that only contains the elements you're interested in.

For example, imagine you have a ring that includes all the whole numbers from 1 to 10. You decide you only want to focus on the even numbers in that ring. You can "cut out" that small piece of the ring to create a localization of the original ring that only has even numbers.

This process of localization can be very useful in commutative algebra because it allows us to study specific elements or subsets of a larger ring in isolation. It also allows us to simplify certain computations and prove certain theorems more easily.