Date: Tue, 12 Jul 2005 21:22:45 GMT
> "Jan Hidders" <jan.hidders_at_REMOVETHIS.pandora.be> wrote in message
>>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.
- Jan Hidders