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Re: Inference rules [was: extracting...]

From: Dan Connolly <connolly@w3.org>
Date: Tue, 18 Jul 2000 00:11:55 -0500
Message-ID: <3973E71B.101C1D05@w3.org>
To: jos.deroo.jd@belgium.agfa.com
CC: " - *www-rdf-interest@w3.org" <www-rdf-interest@w3.org>


jos.deroo.jd@belgium.agfa.com wrote:
> 
> Dan Connolly wrote:
> > I had some inspiration tonight... a design for rules
> > came together:
> 
> > http://www.w3.org/2000/04shoe-swell/inference#
> 
> Cool! (also the list thing...)

Thanks!.

> I see you making variables and rulesteps URI global.

I'm not sure I understand what you mean by that.

> In Euler the http://www.w3.org/2000/04shoe-swell/inference
> example would look like:
> 
> <xx:busy r:source="var:who" r:drain="var:t">
>   <r:junction>
>     <xx:member r:source="var:who" r:drain="var:group"/>
>     <xx:meets r:source="var:group" r:drain="var:t"/>
>   </r:junction>
> </xx:busy>

Ah... thanks. I have glanced at that syntax a few
times without understanding. Now I get it. Er...
no, I don't: that's not legal RDF syntax, is it?
the junction propertyNode can only have one child
element, right?


> One can use the var namespace to have variable predicates
> which can be useful for higher order logic such as in
> ftp://windsor.agfa.be/outgoing/RCEI/NET/euler/authen.rdf
> I guess this must be possible in shoe-swell as well,
> just wonder how ?-)

it's pretty straightfoward; see the "transitive"
example in http://www.w3.org/2000/07/hs78/algernon :

r (x, z) 
     if 
          isa(r, transitive-relations) 
          r(x , y ) 
          r(y, z) 

Recognizing variables by their spelling is one
technique, but it rubs me the wrong way... URIs are
supposed to be opaque (not to mention the illicit
use of an unregistered var: URI scheme). So I model the
fact that a URI is used as a variable in a formula explicitly
using the vars thing (which reduces to a forAll
construct... see the "Relationship to FOPC"
section of .../inference).

Hmm... I wonder if I can express your model for rules
in terms of the FOPC schema I'm working with...
I think so.

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Tuesday, 18 July 2000 01:13:00 GMT

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