Question: Is there an easy way to check that an integral domain is not an EUD?
I know that we have the implication that if $R$ is an EUD it is a PID, so if we can show $R$ is not a PID then it is not an EUD. This seems like the simplest way to check if something is not an EUD, find an ideal which isn't generated by a single element. But because all we need for an integral domain to be an EUD is a norm function, is there in general no easy way to show that no such norm function exists?