Re: relations aren't types?

From: Alfredo Novoa <alfredo_at_ncs.es>
Date: 3 Jan 2004 06:04:32 -0800
Message-ID: <e4330f45.0401030604.4016b1ab@posting.google.com>

"Mikito Harakiri" <mikharakiri_at_iahu.com> wrote in message news:<jjoJb.12$Ma6.43_at_news.oracle.com>...

> > For instance a matrix type does not have representations, a matrix is
> > a matrix :)
>
> Do you imply that matrix is not a scalar type?

Yes. Like tuple, relation, array, vector, etc.

> If we consider matrix as an element of a ring, then it seems to meet
> programming definition of a scalar as type with operations (addition,
> multiplication).

They are neccessary but not sufficient conditions for being a scalar. Non scalars may have operations like addition, multiplication, join and projection.

> If we consider mathematical definition of scalar (as zero
> rank tensor), then matrix (being a second rank tensor) is definetely not a
> scalar.

I don't know about rank tensors, but perhaps we could use them or something similar for a serious definition of scalar and non scalar type. What do you think?

Regards
Alfredo Received on Sat Jan 03 2004 - 08:04:32 CST