ELI5: Explain Like I'm 5

Vitali set

Okay kiddo, let me explain to you what a Vitali set is. Imagine you have a very big pizza and you want to cut it into many equal slices. But instead of just cutting it straight like we usually do, we are going to cut it in a special way. We are going to cut it in such a way that every slice will be a little bit different.

Now, let's take a closer look at this pizza. Suppose we have some tiny grains of sand and we sprinkle them all over the pizza. These grains of sand will now cover some parts of the pizza and leave other parts blank.

But what if we rotate the pizza just a little bit? Now the grains of sand will fall in different places and cover different parts of the pizza. So, if we keep rotating the pizza, the grains of sand will cover all of the pizza eventually, right?

Well, not exactly. There are some places on the pizza where, no matter how much we rotate it, the grains of sand will never cover it completely. And that, my dear little one, is exactly what a Vitali set is. It's a special kind of set that, no matter how you rotate it, there will always be some points left uncovered.

This might sound strange and unbelievable, but it's actually a very important concept in mathematics. It helps us to understand the nature of infinity and to come up with new ideas and theories. So the next time you eat a pizza, remember the story of the Vitali set, and think about all the amazing things you can discover if you keep exploring and learning!