ELI5: Explain Like I'm 5

Reproducing kernel Hilbert spaces

Okay, let's say you have a big toy box with a bunch of different toys in it. You can pick a toy out of the box and play with it, right? Well, imagine that instead of toys, you have something called "functions." These are basically like math-games that you can play with.

Now, some of these functions might be simple, like just adding two numbers together. But other functions might be more complicated, like figuring out what kind of pattern a bunch of numbers follow.

Reproducing kernel Hilbert spaces are like a fancy toy box full of all these different functions. The "Hilbert space" part means that the functions are all set up in a certain way that makes them easy to work with. But the "reproducing kernel" part is the really cool part.

You know how some toys are really special and fun to play with because they can do different things? The reproducing kernel is a special kind of function that's like one of those special toys. It basically helps you to figure out how all the other functions in the Hilbert space work.

So in summary, reproducing kernel Hilbert spaces are like a toy box filled with different kinds of functions, set up in a way that makes them easy to play with, and with a special kind of function in there that helps you figure out how all the other functions work.