Re: Complement in Relational Lattice

From: Vadim Tropashko <vadimtro_invalid_at_yahoo.com>
Date: Fri, 01 Jun 2007 09:30:43 -0700
Message-ID: <1180715443.248707.210320@r19g2000prf.googlegroups.com>

On May 31, 5:26 pm, Marshall <marshall.spi..._at_gmail.com> wrote:
> On May 31, 4:37 pm, Vadim Tropashko <vadimtro_inva..._at_yahoo.com>
> > What you have found is a homomorphism of RL into a boolean algebra
> > which is a product of the boolean algebra of the relation attributes,
> > onto a two element boolean algebra.
>
> Yes, and this "product" is visible in this equation:
>
> (11 \/ H) /\ B
>
> from my second post.

This homomorphism can be expressed explicitly as

A -> (A \/ 00) /\ (A \/ 11)

The formula is dual to the fundamental decomposition identity! Received on Fri Jun 01 2007 - 11:30:43 CDT