Re: MISC: Internet Media Type registration: proposed TAG finding

On Fri, 2002-05-24 at 23:05, Peter F. Patel-Schneider wrote:
> From: Dan Connolly <connolly@w3.org>
> Subject: Re: MISC: Internet Media Type registration: proposed TAG finding
> Date: 24 May 2002 21:34:31 -0500
> 
> > On Fri, 2002-05-24 at 19:09, Peter F. Patel-Schneider wrote:
> > > From: Dan Connolly <connolly@w3.org>
> > > Subject: Re: MISC: Internet Media Type registration: proposed TAG finding
> > > Date: 24 May 2002 16:13:32 -0500
> > [...]
> > > > The author of the best-friend document, by choosing to use
> > > > ont:UniqueProperty class, licensed inferences
> > > > based on the specification of that class. The conclusion
> > > > that "35" is an :age of :margaret is supported
> > > > by the DAML+OIL spec.
> > > 
> > > Yes, but not by the RDF spec, and any agent has no business labelling
> > > anything as RDF inferences that are not sanctioned by the RDF model theory.
> > 
> > Hmm... that's one way to think of 'RDF inferences'.
> > It's not one that appeals to me.
> > 
> > > > I can think of two agents (cwm and Euler) that
> > > > do a lot more than simple entailment, when
> > > > asked to. I think of them as RDF agents.
> > > 
> > > They are not.
> > 
> > Er... I accept that as your opinion.
> > I disagree.
> 
> Then it is up to you to show how the RDF specification admits cwm and Euler
> as RDF agents.

You seem to think it's reasonable for you to introduce a
term (RDF agent) into the conversation, without defining it,
then define it later, and then hold me to your definition
as if I had accepted it.

I repeat: I don't agree to your definition of 'RDF agent',
i.e. something that computes inferences that are
valid per the RDF model theory, and no others.

>  I claim that they are not, and back up my claim by your
> statement that cwm and Euler do more than is santioned by the RDF model
> theory. 

When I first saw the term 'RDF agent' in this thread, I
inferred that it meant something that would draw all
conclusions that are sanctioned by the RDF model
theory, plus any others it was instructed to make.
By that definition, cwm and Euler are
RDF agents.

> > >  If they label their entailments as RDF entailment then they
> > > are being deceitful, moreover.
> > 
> > They don't label their entailments as RDF simple entailment.
> > They only make conclusions that they're asked to make;
> > you have to tell Euler and cwm to include axioms
> > about DAML+OIL in order for them to make these
> > conclusions. There's nothing deceitful going on.
> 
> Anyone who labels the results as valid RDF consequences is incorrect,

'valid RDF consequences' ... another new term.
I clearly didn't label the results of cwm nor Euler with that
term; I haven't used it at all in this thread.

'valid RDF consequences' doesn't seem to bring any notions
into the conversation that aren't captured by 'simple entailment';
can't we stick to the terms that are defined to our mutual
satisfaction in documents that are readily available to
the readership of this forum?

http://www.w3.org/TR/2002/WD-rdf-mt-20020429/#entail


I'll say again: cwm and Euler don't label their inferences
as RDF simple entailments.

> and
> if they know that they should know, is being deceitful.  Anyone who calls
> the results RDF is verging on deceit.

Hmm... cwm writes out its results in a format that conforms
to the RDF syntax spec. That's not RDF? I'm pretty sure
I don't understand what you mean by 'calling the results RDF'.

> 
> > > > But yes, the conclusion that "35" is an age of :margaret
> > > > isn't supported by simple entailment alone, and
> > > > justification of that conclusion needs to be clear
> > > > about including the DAML+OIL spec.
> > > 
> > > How can this be done in RDF?  It cannot.
> > 
> > I disagree.
> > 
> > If you had some argument beyond
> > assertion, we might productively discuss it further.
> 
> Well, there is no way in the RDF model theory to entail that two different
> URIrefs denote the same resource.  The DAML+OIL meaning of UniqueProperty
> (or whatever the name for making a property be functional is) can be used
> to DAML+OIL-entail that two different URIrefs denote the same resource.
> QED

Hmm... you introduced the term/phrase 'do in RDF' into the conversation;
now you clarify that you mean 'reach conclusions
that are simple entailments, and no others'.
I wish you had said so in the first place.

My position on media types for the Resource Description Framework
is that the RDF model theory isn't the end of the story for the
whole framework; folks that send documents labelled
with application/rdf+xml (or whatever) definitely license
all simple entailments. But they also license other inferences,
based on the vocabulary they choose to use in their document.

So just because an agent's inferences aren't simple entailments
doesn't mean they're false, wrong, deceitful, or unjustifyable.
On the contrary: I suggest there's an emerging protocol for
introducing new vocabularies into the framework, and that
documents labelled with this media type are part of that protocol.


> > > > > > > Sure, but the non-understood part may completely change the meaning of the
> > > > > > > other part,
> > > > > > 
> > > > > > No, I don't think so...
> > > > > 
> > > > > Why not?  What about 
> > > > > 
> > > > > 	<fol:negation>
> > > > > 	  <fol:statement>
> > > > > 	    <rdf:Person rdf:about="#John">
> > > > > 	      <loves rdf:resource="#Mary">
> > > > > 	    </rdf:Person>
> > > > > 	  </fol:statement>
> > > > > 	</fol:negation>
> > > > 
> > > > I'm not sure how to parse that. If I presume that fol:negation
> > > > is an RDF typednode, and convert to (something close to) KIF, I get:
> > > > 
> > > >   (exists (?n)
> > > >     (rdf:type ?n fol:negation)
> > > >     (fol:statement ?n #John)
> > > >     (rdf:type #John rdf:Person)
> > > >     (loves #John #Mary)
> > > >   )
> > > > 
> > > > so... ?n is a negation, and it's somehow related to John.
> > > > I think you meant to express something like
> > > >   (not (loves John Mary))
> > > 
> > > That is indeed what I meant. I expressed it in RDF syntax, which according
> > > to you, should be perfectly fine.  I used my extension to RDF reasoning,
> > > which, according to you, should also be perfectly fine.
> > 
> > I can't make sense of this extension. Maybe you could explain
> > how it works a little more generally than this one example.
> > I don't understand how the fol:negation class's specification
> > reaches out thru #John to the (loves #John #Mary) triple.
> 
> But according to your rules, any method of providing meaning for this
> extension is adequate.

No, only those that are monotonic. i.e. when you specify an extension,
you can only throw out models; you can't put any back in.

>  OK, the method that I will use is that it means
> what I mean it to mean.  

So long as it's monotonic, then you haven't provided an example
that ...

> > > > > > > [...] the non-understood part may completely change the meaning of the
> > > > > > > other part,


> This is no harder for an RDF-only agent to understand than the DMAL+OIL
> meaning of daml:UnambiguousProperty.
> 
> > In particular, I don't understand it well enough to
> > see if it's non-monotonic.
> 
> Why should this be a problem?

Because that's against 'my rules'; i.e. the rules I'm
suggesting for this new media type.

> > > > but that's really awkward to do in RDF, but I suppose
> > > > it could look like:
> > > > 
> > > >   <fol:Negation>
> > > >     <fol:predicateSymbol>http:...#loves</fol:predicateSymbol>
> > > >     <fol:subjectSymbol>http:...#John</fol:predicateSymbol>
> > > >     <fol:objectSymbol>http:...#loves</fol:objectSymbol>
> > > >   </fol:Negation>
> > > > 
> > > > where fol:Negation is specified ala:
> > > > 
> > > >   (forall (?n ?s ?p ?o)
> > > >     (<=>
> > > >       (and
> > > >         (predicateSymbol ?n ?p)
> > > >         (subjectSymbol ?n ?s)
> > > >         (objectSymbol ?n ?o)
> > > >         (wtr
> > > >            '(not (holds `(str->sym ?p) `(str->sym ?s) `(str->sym ?o))) )
> > > >       )
> > > >       (rdf:type ?n fol:Negation)
> > > >   )
> > > > 
> > > > But even in that case, I *only* eliminate models when I
> > > > learn the meaning of fol:Negation (i.e. when I add that axiom).
> > > 
> > > Yes, and this is no longer RDF.
> > 
> > I accept that as your opinion. I disagree.
> > Argument by assertion is really no fun.
> 
> Well, how could it be RDF?  It doesn't match any syntax for RDF.  QED


Please allow me to clarify; I might publish, at the address
of fol:Negation, something ala:

<rdfs:Property rdf:about="#specInKIF">
  <rdfs:subPropertyOf rdf:resource="http:.../rdf-schema#comment">
</rdfs:Property>

<rdfs:Class rdf:about="#Negation">
  <specInKIF>
   (forall (?n ?s ?p ?o)
     (<=>
       (and
        (predicateSymbol ?n ?p)
         (subjectSymbol ?n ?s)
         (objectSymbol ?n ?o)
         (wtr
            '(not (holds `(str->sym ?p) `(str->sym ?s) `(str->sym ?o))) )
      )
      (rdf:type ?n fol:Negation)
  )
  </specInKIF>
</rdfs:Class>

> [...]

> peter
-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/

Received on Wednesday, 29 May 2002 21:27:48 UTC