ELI5: Explain Like I'm 5

Köthe conjecture

The köthe conjecture is like a really big and complicated puzzle that mathematicians have been trying to solve for a long time. It's all about something called "infinite-dimensional spaces", which are like really big rooms where you can keep adding more and more things forever without ever running out of space.

A long time ago, a really smart mathematician named Helmut Köthe came up with an idea for how to solve this puzzle. He thought that there was a special kind of equation that could help us figure out how to put things together in these infinite-dimensional spaces. But nobody has been able to prove that this idea is true or figure out a way to solve the puzzle yet.

So basically, the köthe conjecture is about trying to figure out if Helmut Köthe's idea is right or not, and it's a really hard puzzle that lots of really smart mathematicians are still working on.