Re: Relational Lattice, what is it good for?
From: vc <boston103_at_hotmail.com>
Date: 18 Feb 2006 18:25:40 -0800
Message-ID: <1140315940.011254.78600_at_z14g2000cwz.googlegroups.com>
Date: 18 Feb 2006 18:25:40 -0800
Message-ID: <1140315940.011254.78600_at_z14g2000cwz.googlegroups.com>
Mikito Harakiri wrote:
[...]
> A(x,y) || B(y,z) = { y | exists x A(x,y) or exists z B(y,z) }
The above would be an empty set if both relations were empty, or an undefined expression if either or both were non-empty since it's unclear what domain 'y' ranges over. Received on Sun Feb 19 2006 - 03:25:40 CET