Re: Proposal: 6NF

From: vc <boston103_at_hotmail.com>
Date: 13 Oct 2006 08:22:08 -0700
Message-ID: <1160752928.197097.241340@m73g2000cwd.googlegroups.com>

Jan Hidders wrote:
> vc wrote:
> >
> > More interestingly, why bother with a trivial fact that Z may be
> > [considered] a subset of R in whatever sense ?
>
> Because you want a simple formalization of subtyping a la Cardelli and
> Wegner where subtyping coincides with being a subset. It means that the
> meanig of the + operation in (a + b) can be considered independent of
> the type of a and b.

RIght, but my understanding of the OOP stuff leads me to believe that a subtype should '"inherit" its type operations. If so, assuming R is our base type, what do we do about division in Z (regarded as an R subtype) ;) ?

>
> -- Jan Hidders
Received on Fri Oct 13 2006 - 10:22:08 CDT