Technically the relational model uses the term relation to refer to an unordered set of tuples, where every tuple has a key (one or more elements) to uniquely identify it, and every tuple has the same number of items, of the same type. Tables are relations. So are the results of a query, which can include joins.
> > there’s nothing in [Codd’s] principles that require tables/rows of tuples.
You're misquoting; is that intentional? The post you're replying to says the principles that inspired/predate Codd don't require tables/tuples. Thus, the details of Codd's relational model are irrelevant.
If I misunderstood the principles you refer to I apologize. Codd's relational rules and designs for relational databases developed from relational algebra theory, which was introduced by... Edgar F. Codd.
Have you read Codd’s Rules #1 and #2? Pretty clear on this point.
https://en.wikipedia.org/wiki/Codd%27s_12_rules
Technically the relational model uses the term relation to refer to an unordered set of tuples, where every tuple has a key (one or more elements) to uniquely identify it, and every tuple has the same number of items, of the same type. Tables are relations. So are the results of a query, which can include joins.