i didn't think the invariant subspace problem would be an embarrassment. i guess it's not all that hard for finite dimensions. only one person mentioned goldbach's conjecture, & nobody said anything about perfect numbers. they seem pretty easy to understand but hard to say interesting things about. same with fermat's last theorem & the 4-colour problemA mathematical embarrassment (ME) is a problem that should have been solved by now. An ME usually is easy to state, seems approachable, and yet resists all attempts at an attack. There may be many reasons that they are yet to be solved, but they “feel” like they should have been solved already.
Last edited by a moderator: