@joelving sure, but everything is a reference. replies are just a special reference that indicate you are responding to something. the attribution is just a special reference indicating authorship.
the thing i’m interested in finding is: how can we describe the “quote” relationship, if such a thing even really exists?
@trwnh Maybe I'm not getting what you're trying to achieve. My point was that it will probably be impossible to enumerate every kind of relationship between two posts. We have "replies", "for example", "see also", "source", "rebuttal", "review", and the list goes on.
Am I missing what you're after?