Re: "Armstrong's axioms" augmentation - help plz

love boat via DBMonster.com wrote:
> I understand the Augmentation rule:
> { X -> Y } |= XZ -> YZ
>
> but I don't understand why the rule can also be stated as:
>
> { X -> Y } |= XZ -> Y
>
> Why is this?
>

1. YZ -> Y (reflexivity)
2. XZ -> YZ (given)
3. XZ -> Y (transitivity)

finally, a question i can answer,
p Received on Mon Mar 07 2005 - 12:23:23 CST