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Re: Constraints and Functional Dependencies

From: Cimode <cimode_at_hotmail.com>
Date: 1 Mar 2007 06:13:05 -0800
Message-ID: <1172758385.326995.54710@n33g2000cwc.googlegroups.com>


On Feb 27, 10:44 pm, mAsterdam <mAster..._at_vrijdag.org> wrote:
> Marshall wrote:
> > mAsterdam wrote:
> >> Does this (unicode 2261)
> >> come through: ≡ or does it look like gibberish?
>
> > Yes, that's the one. Comes through just fine. (It's always
> > a shock when my browser renders anything more challenging
> > than ASCII.)
>
> Brace yourself before you scroll down :-)
>
> Playing a little with Unicode:
>
> Mp (Marshall/paul) referential integrity =def=
> forall R(a): exists S(b): a = b
>
> becomes
>
> R(a) references S(b) ≡
> ∀R(a): ∃S(b)| a=b
>
> or
>
> (using レ = katakana re for references)
>
> R(a) レ S(b) ≡
> ∀R(a): ∃S(b)| a=b
>
> Classic referential integrity (no need, says paul c)
>
> (ル = ru for references unique)
>
> R(a) ル S(b) ≡
> ∀R(a): ∃!S(b)| a=b

Thank you for the formatting effort...For better formalism, domain of values -a- and -b- must be specified

So I may suggest ...

--Reference
R(a) レ S(b) ≡∀a E R,∀R(a): ∃b E S | ∃S(b) | a=b

--Reference Unique
R(a) ル S(b) ≡∀a E R,∀R(a): ∃!b E S | ∃!S(b) | a=b

Hope it does not get messed up in web format... Received on Thu Mar 01 2007 - 08:13:05 CST

Original text of this message

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