Re: Relational Lattice, what is it good for?

Mikito Harakiri wrote:
> vc wrote:
> > Mikito Harakiri wrote:
> > [...]
> > > Working out the left side of distributivity equation we have:
> > >
> > > A && (B || C) = { (x,v,t) | A(x,t) and ( exists y B(y,v,t) or exists z
> > > C(z,v,t) ) }
> >
> > With the relations B and C both being empty, you'd get an emtpy set
> > regardless of A.
>
> Yes.
>
> > WIth either B or C (or both) being non-empty, you'd
> > get {(x, v, t) | A(x,t) }
>
> Why? The v variable (as well as t) is binded with the "exists y
> B(y,v,t) or exists z
> C(z,v,t)" expression.
>
> > where it's unclear what domain 'v' ranges
> > over. Is that what you've intended ?
>
> I don't see domain dependence there. Can you be more specific?

Sorry, I misunderstood the notation. The expression looks correct. Received on Mon Feb 20 2006 - 02:30:06 CET