@DanielFischer (or any other diamond on any other website): Out of sheer curiosity, can diamond users override acceptance of answers? Namely, can they unaccept or accept an answer?
I know you can cause unacceptance by deleting and undeleting. But can the check mark be manipulated directly? is my question.
@DanielFischer I'm not good with intuitive understanding geometry, but surely there are methods to detect if a given set is convex. Maybe these apply here as well.
What can be said for sure is that convex compact sex has an extremal point.