Re: more closed-world chatter

Vadim Tropashko wrote:
> I suggest [anti]join as a generalized minus. The generalized Date
> identity is:
>
> (A /\ B) \/ (A /\ 00) = A \ (A \ B)
>
> where /\ is join, \/ is generalized union, and \ is antijoin.

So the left side is a semijoin, right? What do you mean by the phrase "The generalized Date identity"?

-- 
Jon