Re: Relational lattice
From: Vadim Tropashko <vadimtro_invalid_at_yahoo.com>
Date: 14 Mar 2005 15:50:29 -0800
Message-ID: <1110844229.966246.275290_at_g14g2000cwa.googlegroups.com>
Date: 14 Mar 2005 15:50:29 -0800
Message-ID: <1110844229.966246.275290_at_g14g2000cwa.googlegroups.com>
How about small counter example?
Consider
R=
x y
- -
1 2
2 2
2 3
I suggest that
X = X12 join X34 join X56
where
X12=
x y
- -
1 2
2 2
2 3
3 3
3 2
X34=
x y
- -
1 2
2 2
2 3
3 3
3 2
1 3
X56=
x y
- -
1 3
is a solution that meets conditions 1-4. (The fact that x5=1 and x6=3 is the only pair is especially handy when checking the above conditions). Received on Tue Mar 15 2005 - 00:50:29 CET