Nonpareil
The Terrible Trivium
One can define X as complete OR incomplete
Which is not a definition of "successor".
{X}$Y OR {X}~$Y that is exactly the definition of how {X} is related to X as its successor.
No, that says "{X} could be the successor of Y, or it could not be".
That is not a definition of "successor".
No one cares about "complete" or "incomplete" right now. We can move on to those once you have defined "successor".