# Re: completeness of the relational lattice

From: Vadim Tropashko <vadimtro_invalid_at_yahoo.com>

Date: Tue, 26 Jun 2007 14:31:21 -0700

Message-ID: <1182893481.352583.84760_at_e9g2000prf.googlegroups.com>

> (32b) = R(x,y) * <x> * <y>

> (28) = R(x,y)

Date: Tue, 26 Jun 2007 14:31:21 -0700

Message-ID: <1182893481.352583.84760_at_e9g2000prf.googlegroups.com>

On Jun 26, 1:48 pm, Jan Hidders <hidd..._at_gmail.com> wrote:

> (R(x,y) * []) + (R(x,y) * W)

> (22) = [x,y] + (R(x,y) * W)> (9) = ([x,y] + R(x,y)) * ([x,y] + W)

*> (10) = R(x,y) * ([x,y] + W)**> (11) = R(x,y) * (([x] * [y]) + W)**> (9) = R(x,y) * (([x] + W) * ([y] + W))*> (32b) = R(x,y) * <x> * <y>

> (28) = R(x,y)

A + (B*C) = (A+B) * (A+C)

the attributes of B are required to be a superset of A, not subset. Received on Tue Jun 26 2007 - 23:31:21 CEST