ELI5: Explain Like I'm 5

Generalized Riemann hypothesis

The Generalized Riemann Hypothesis is like a big puzzle that mathematicians are trying to solve. It's about something called prime numbers, which are really important for a lot of things in math.

Think of your favorite number - let's say it's 10. You can make 10 by multiplying two smaller numbers together: 2 x 5 = 10. But if we try to do that with some other numbers, like 4 or 6 or 8, we can't find any two numbers that multiply together to make them. These are called composite numbers, and they're made up of other smaller numbers multiplied together.

But then there are numbers like 2, 3, 5, 7, 11, 13... These numbers can't be broken down into smaller numbers multiplying together - they can only be divided by 1 and themselves. These are called prime numbers, and they're really important because they play a big role in things like cryptography (which helps protect our passwords and credit card numbers online).

The Generalized Riemann Hypothesis is all about understanding how prime numbers are distributed along the number line. Mathematicians have already figured out a lot about prime numbers - for example, there are infinitely many of them. But there are still a lot of questions we don't know the answers to - for example, is there always another prime number that's just a little bit bigger than the last one we found?

The Generalized Riemann Hypothesis is a very complicated idea, but it basically says that if we look at a certain formula that involves prime numbers and some other stuff, we can predict where the prime numbers will show up on the number line. If we can solve this puzzle and prove that the Generalized Riemann Hypothesis is true, we'll have a better understanding of how prime numbers work - and that can help us do all kinds of cool things in math and science.