ELI5: Explain Like I'm 5

Henri Lebesgue

Henri Lebesgue was a very smart man who lived a long time ago. He was born in France in 1875 and he became famous for something called "Lebesgue Integration".

Now, you might be wondering what on earth "Lebesgue Integration" means. Well, integration is a fancy word that means putting things together to make a bigger thing. It's kind of like putting together a puzzle.

But instead of putting together a puzzle with pieces of cardboard, Henri Lebesgue was putting together something called functions. Functions are another fancy word that mathematicians use to describe things that take one number (or several numbers) and turn them into another number.

For example, let's say you have some apples. You might have a function that takes the number of apples you have and tells you how much money those apples are worth. That's a function!

Now, Henri Lebesgue's special way of putting functions together was really important because it helped mathematicians solve some really tricky problems. It's kind of like having a secret weapon that helps you win a battle.

So, that's why Henri Lebesgue is really famous in the world of math. He was really good at putting pieces of puzzles together, and he helped other mathematicians solve really hard problems.