Re: Storing data and code in a Db with LISP-like interface
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Fri, 21 Apr 2006 18:33:19 GMT
Message-ID: <Pz92g.63780$VV4.1192456_at_ursa-nb00s0.nbnet.nb.ca>
>
>
> Of course not. I am sure this is a rhetorical question but I cannot
> ascertain its point - I think you are referring to relational algebra,
> but this is not the same as the use of negation in explicit
> declarations such as P(x) || ¬Q(y) (for instance). In RM the user has
> to remember this predicate. In Prolog, the program memorises it for
> you, for good or for bad. To compare the two is hence comparing apples
> and oranges.
>
>
> I am regurgitating from memory - I think it _may_ have been Codd
> speaking of the active decision on his part to use the subset of
> predicate logic that he did, but I will have to dig it out in the piles
> of papers I have.
Date: Fri, 21 Apr 2006 18:33:19 GMT
Message-ID: <Pz92g.63780$VV4.1192456_at_ursa-nb00s0.nbnet.nb.ca>
JOG wrote:
> Bob Badour wrote:
>
>>JOG wrote: >> >>>Bob Badour wrote: >>> >>>>Alvin Ryder wrote: >>>> >>>>>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. >> [snip] >>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.
The point is the relational model basically supports both with the one small requirement that one must specify one's universe. I do not understand what you mean by 'has to remember this predicate'.
>>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.
Somehow, I doubt Prolog returns many infinite sets.
> Either way, prolog is a dwindling language anyhow:
> (http://www.tiobe.com/tpci.htm)
I don't see where you established it is dwindling. Other than the fact it might be included in the first 50 languages, I doubt it ever occupied a spot in the top 50. Received on Fri Apr 21 2006 - 20:33:19 CEST