Re: Functional dependency is multivalued dependency

From: Mikito Harakiri <mikharakiri_nospaum_at_yahoo.com>
Date: 5 May 2006 19:06:04 -0700
Message-ID: <1146881164.595964.241870@j33g2000cwa.googlegroups.com>

Mikito Harakiri wrote:
> Jan Hidders wrote:
> > Do you already know how to represent the FD in RL equations?
>
> I(x, y_1, z_1) /\ I(x, y_2, z_2) /\ `y_1!=y_2` = `x y_1 y_2 z_1 z_2`
> ...

Just yesterday I came across an article about dependencies in BRA (although I fail to recollect the reference!). The dependency equation in BRA is just

R ^R R = R

which demands R to be regular in other words. Geometrically, a regular relation is a union of parallelograms, so that the redundant information can be compressed. Perhaps it might be easier to express functional dependency in BRA equationally? Received on Fri May 05 2006 - 21:06:04 CDT