Lévy hierarchy

Okay, so imagine you have a bunch of boxes, and inside each box is a toy. The boxes are organized in a certain way, with some boxes being bigger than others and containing more toys. The Lévy Hierarchy is like a way of sorting these boxes based on how many toys they have inside.

At the bottom of the hierarchy are the smallest boxes, which only have one toy inside. As you move up the hierarchy, the boxes get bigger and bigger and contain more and more toys.

But here's the catch - the boxes in the Lévy Hierarchy aren't just sorted by size or number of toys. They're sorted based on how hard it is to figure out how many toys are inside.

So the boxes at the bottom of the hierarchy are really easy to figure out - you can just open them up and see that there's only one toy inside. But as you move up the hierarchy, the boxes get trickier and trickier to figure out. You might have to solve a puzzle or use some really advanced math to figure out how many toys are inside.

Overall, the Lévy Hierarchy helps us understand how difficult certain mathematical problems are to solve. It's like a big ladder of boxes that we can climb up to challenge ourselves and see just how hard we can push our brains!