Re: Normalisation
Date: Fri, 8 Jul 2005 11:15:29 +0200
Message-ID: <MPG.1d385e09db0b29629896ed_at_news.ntnu.no>
In article <Ezeze.139544$p21.7384199_at_phobos.telenet-ops.be>,
jan.hidders_at_REMOVETHIS.pandora.be says...
> >>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.
> >
> > You'll have to educate me on the difference between "proper class" and
> > "domain", I'm afraid. The term "class" is used for so many slightly
> > different things.
>
> http://en.wikipedia.org/wiki/Class_(set_theory)
Are you saying that the "domain of sets" is not a domain either?
And that relation-valued and set-valued attributes are contradictions in terms, since relation and set are not domains?
> > Should I be forbidden from treating "relation" as a (generic) domain
> > when defining this operator? Why?
>
> Because by definition it isn't, and redefining the notion of domain such
> that it is, is not that easy without either running into paradoxes or
> getting a notion which it is almost impossible to reason about.
> > Would you allow this operator if it were system-defined?
>
> I am not disallowing anything.
Please don't be coy or cryptic. Do you mean that *you* do not disallow anything, but mathematical theory does? Or that being forbidden and being disallowed is different?
-- JonReceived on Fri Jul 08 2005 - 11:15:29 CEST