Re: Objects and Relations

On 26 feb, 13:18, "Cimode" <cim..._at_hotmail.com> wrote:

> > > In RM, a domain is *not* the same* as a type or a relation.
>
> > In RM domain is used as a synonym of type and it is completely
> > different to relation.
>
> Disagreed. You can not equate both.> > (

Why?

I can admit that a type is a domain and a set of operators which act on such domain. But domain is mostly used as a synonym of type. The difference is not important because a domain always imply a set of operators, so a domain always imply a type.

> > > domain = set of *possible* values for which a relation draws
> > > *possibly* values
>
> > When you say "relation" we assume that you mean "relation value". If
> > you mean "relation variable" please write: "relation variable" or
> > "relvar".
>
> Thank you for your educational intent I already know that.

Then what you wrote does not make any sense.

> No, relations are equated to relation values only in the computing
> community. I prefer to keep the mathematical distinction between
> relation and relation value.

Mathematical relations are relation values.

I think that you don't know what a relation value is at all.

> Meaning that a domain potentially defines a type. It becomes a domain
> only when values are drawn from it. It is a subtlety that is
> necessary to truly understand RM.

Where did you get this strange idea?

Regards Received on Mon Feb 26 2007 - 13:51:45 CET