Earlier quoted context omitted.
> Having a business where you can go to a physical office and show up with ID so you can get your account back would solve this problem. I've wanted something similar, combined with a tree approach to account recovery where the effort for recovery can vary depending on the importance of the account. Say I lose access to my McDonald's account. That's not a very important account. It just contains some reward points th…
> My domain name is so important, since it is in the ultimate recovery path for so many descendant nodes, it would probably have at least two parent nodes (I didn't say anything about the tree having to be a binary tree). If your domain name can have multiple descendant nodes and multiple parent nodes, is that still a tree?
Actually I guess it doesn't even have to acyclic. You just need a directed graph where that has a non-empty set R of nodes such that (1) nodes in R do not have incoming edges, and (2) every node that has an incoming edge can be reached by some path that starts in R.