Re: Transitive Closure

From: Alfredo Novoa <alfredo_at_ncs.es>
Date: Fri, 14 May 2004 18:37:37 GMT
Message-ID: <40a51057.8060810@news.wanadoo.es>

On Fri, 14 May 2004 10:23:36 -0700, "Mikito Harakiri" <mikharakiri_at_iahu.com> wrote:

>Then, it's inconvenience, at least. Trees are usually represented with
>relations that combine nodes and edges together, and you effectively
>prohibit TC working with trees.

You can apply the TC over a projection.

>From bigger perspective, it looks more than just a minor limitation. It's
>breaking relational closure.

No because TC returns a relation.

What breaks relational closure is Tutorial's D "from" operator, but it is intended to do that.

>What other relational operator is not allowed
>to be applied to arbitrary relation?

You can invent many of them.

Regards
Alfredo Received on Fri May 14 2004 - 13:37:37 CDT