Re: Normalisation
Date: Tue, 12 Jul 2005 19:44:47 -0400
Message-ID: <gY2dnSJOfth2yEnfRVn-tg_at_comcast.com>
"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).
Thanks.
>
> -- Jan Hidders
Received on Wed Jul 13 2005 - 01:44:47 CEST