Re: Distributivity in Tropashko's Lattice Algebra

"Mikito Harakiri" <mikharakiri_nospaum_at_yahoo.com> wrote in message news:1124225375.601615.162210_at_g47g2000cwa.googlegroups.com...
>
> vc wrote:
>> A union '00' = '00'.
>
> This can't be.
>
> A union '00' = '00'
>
> implies 00 < A, and the partial order "<" being the same in upper and
> lower semilattice implies that
>

OK, apparently your definition of '00' is different from mine. What relation does '00' stand for ?

> A join '00' = A
>
> which we saw isn't.
>
>> What's rowid(A) ?
>
> A set of rowids? This is a dual concept to the relation header: table
> columns are identified by table attribute names, while the rows are
> identified by rowids. Unlike the set algebra of attribute names, the
> algebra of rowids doesn't seem to be boolean.
>

Let's figure out what relation '00' referes to before tacling rowids. Received on Wed Aug 17 2005 - 12:51:06 CEST