ELI5: Explain Like I'm 5

Cereceda's conjecture

Cereceda's conjecture is a big puzzle that mathematicians are trying to solve. Imagine you have a big treasure box filled with numbers. The numbers inside the box all have something in common - they are all bigger than one (you can't put 0 or 1 in the box).

The mathematicians want to know if they can take some of these numbers out of the box and multiply them together to get a special kind of number. This special number is called a power of two. It looks like this: 2, 4, 8, 16, 32, 64, and so on.

But here's the tricky part: the mathematicians want to keep taking numbers out of the box and multiplying them together to get different power of two numbers. They want to keep doing this until they can't make any more power of two numbers.

For example: let's say the numbers in the treasure box were 2, 3, 5, 7, 11, 19, and 23. The mathematicians would try taking out the number 3 and multiplying it by 5 and 7. They would get 3 x 5 x 7 = 105. This is not a power of two, so they would try something else. Maybe they would take out the number 2 and multiply it by 19 and 23. They would get 2 x 19 x 23 = 874. This is also not a power of two. They would keep trying different combinations until they couldn't make any more power of two numbers.

The question is: can they always do this, no matter what numbers are inside the treasure box? That's what Cereceda's conjecture is trying to figure out. People are still trying to solve this puzzle, but it's a big challenge!