Question about Datalog F3

Very cool!

Could you elaborate on what it means that DatalogF3 is a ‘PER’?

The above still doesn’t fully explain what it is. Since if it is not TRUE, what is it then? Well the answer is, since SQL has 3-valued logic, it is UNKNOWN and not FALSE.

=          NULL      0         1 
0          UNKNOWN   TRUE      FALSE
1          UNKNOWN   FALSE     TRUE

Edit 01.03.2021:
Dont forget to like and share DatalogF3 on Twitter. Yesterday I encountered a PhD student in Logic from Vienna. He didn’t know Free Logic. So these institutions could improve!