set builder notation for relational division
From: Marshall <marshall.spight_at_gmail.com>
Date: 13 May 2007 09:18:42 -0700
Message-ID: <1179073122.442120.70250_at_u30g2000hsc.googlegroups.com>
I was trying to come up with a set builder notation description of relational division. I didn't like what I had, so I went agoogling.
Date: 13 May 2007 09:18:42 -0700
Message-ID: <1179073122.442120.70250_at_u30g2000hsc.googlegroups.com>
I was trying to come up with a set builder notation description of relational division. I didn't like what I had, so I went agoogling.
I found this:
A(a,b)
B(b)
A / B = {(a) | exists (a, b) in A forall (b) in B}
If we want to generalize that, we could say
A(a,b)
B(b,c)
A / B = {(a, c) | exists (a, b) in A forall (b, c) in B}
Yes? No? Anyone have a formula they like better?
Marshall Received on Sun May 13 2007 - 18:18:42 CEST