set builder notation for relational division

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 - 11:18:42 CDT