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Home -> Community -> Usenet -> comp.databases.theory -> Re: Relational Lattice, what is it good for?
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. WIth either B or C (or both) being non-empty, you'd get {(x, v, t) | A(x,t) } where it's unclear what domain 'v' ranges over. Is that what you've intended ?
[...] Received on Sat Feb 18 2006 - 20:20:09 CST
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