Table Dum

This is the relation that has no attributes and no tuples. It plays the role of False.

I've used this for years but have never heard it called 'TableDum'. It's useful to note that, inversely, 'True' is the relation with no attributes and one tuple (unit or ()). Does that also have a dum name?

Yes, it is TableDee

["Table Dum" and "Table Dee" are terminology created by HughDarwen, one of the authors of TheThirdManifesto.]

Ah. Inspired, I suspect, by TweedleDee and TweedleDum of LewisCarroll or the nursery rhymes. I suppose it's nice to have names for them. I just considered it one of those nameless patterns.