# Re: Normalisation

From: VC <boston103_at_hotmail.com>

Date: Wed, 13 Jul 2005 17:28:41 -0400

Message-ID: <pp6dncXrsOkVGkjfRVn-1g_at_comcast.com>

>> "Jan Hidders" <jan.hidders_at_REMOVETHIS.pandora.be> wrote in message

Date: Wed, 13 Jul 2005 17:28:41 -0400

Message-ID: <pp6dncXrsOkVGkjfRVn-1g_at_comcast.com>

> VC wrote:

>> "Jan Hidders" <jan.hidders_at_REMOVETHIS.pandora.be> wrote in message

*>> news:FwWAe.143403$A03.7623726_at_phobos.telenet-ops.be...**>>**>>>VC wrote:**>>>**>>>>"Jan Hidders" <jan.hidders_at_REMOVETHIS.pandora.be> wrote in message**>>>>news:AyVye.138732$g63.7370802_at_phobos.telenet-ops.be...**>>>>[...]**>>>>**>>>>**>>>>>Ah, but now you are using the domain or relations, right? There is a**>>>>>problem with that domain. It doesn't exist. The collection of all**>>>>>relations is a proper class, and not a set, but domains have to be**>>>>>sets.**>>>>**>>>> The collection of all relations is most certainly a set, and**>>>> therefore, a domain, domain being a synonym of set. The term "proper**>>>> class" implies that you talk in terms of set theory other than ZF (**>>>> Zermelo - Fraenkel ) ). There is no need to do so for the reltional**>>>> model unless you can show there is ;)**>>>**>>>There is indeed no such need, unless of course you want to define the**>>>domain of relations, which you cannot do in ZF.**>> The onus of proof of such impossibility is squarely on your shoulders.**>> Please oblige (define a collection/domain of relations, within ZF, which**>> ain't a set).*> > Defining a collection of relations within ZF that is not a set, is neither > here nor there.

I am sorry but your response does not make any sense whatsoever. What is "neither here nor there" supposed to mean ?

Please define a collection of relations obeying ZF axioms and show it's not a set.

>

> -- Jan Hidders
Received on Wed Jul 13 2005 - 23:28:41 CEST