Re: Storing data and code in a Db with LISP-like interface

From: JOG <>
Date: 21 Apr 2006 10:59:05 -0700
Message-ID: <>

Bob Badour wrote:
> JOG wrote:
> > Bob Badour wrote:
> >
> >>Alvin Ryder wrote:
> >>
> >>>Neo wrote:
> >>>
> >>>
> >>>>I believe I have already surpassed RM. And as far as I can
> >>>>tell, linked-lists are not even as flexible as RM.
> >>>
> >>>I agree linked-lists aren't as powerful as the RM but LISP and Prolog
> >>>are not merely about lists.
> >>>
> >>>Both Prolog and LISP can represent information and indeed knowledge
> >>>well beyond the RM, that's why they are popular with the ai community!
> >>
> >>Given the standard definitions of information and knowledge, that's a
> >>rather astounding claim. Do you have anything that might back it up?
> >
> >
> > Prolog models a greater subset of predicate logic than relational
> > theory due to its inclusion of negation and disjunction. As such it has
> > been traditional popular in classic-AI as the basis of inference
> > engines. Whether this allows it to offer a better representation of
> > 'knowledge' is up for debate.
> It would be a short debate. The standard definitions define data as that
> subset of information represented suitably for machine processing,
> making knowledge that subset of information lacking such suitable
> representation.

Yes, and the debate between _us_ would be short to non-existent. However this would not be the case with others in the AI/SemWeb community who have already been debating for decades.

> I direct you to Dijkstra's famous quote regarding submarines.

That would be preaching to the converted.

> Are you suggesting that NOT is not negation or that OR is not
> disjunction?

Of course not. I am sure this is a rhetorical question but I cannot ascertain its point - I think you are referring to relational algebra, but this is not the same as the use of negation in explicit declarations such as P(x) || Q(y) (for instance). In RM the user has to remember this predicate. In Prolog, the program memorises it for you, for good or for bad. To compare the two is hence comparing apples and oranges.

> I am curious what basis you think you have for the
> astounding statement: "Prolog models a greater subset of predicate logic
> than relational theory due to its inclusion of negation and disjunction."

I am regurgitating from memory - I think it _may_ have been Codd speaking of the active decision on his part to use the subset of predicate logic that he did, but I will have to dig it out in the piles of papers I have.

Either way, prolog is a dwindling language anyhow: ( Received on Fri Apr 21 2006 - 19:59:05 CEST

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